diff options
Diffstat (limited to 'lib/esan')
-rw-r--r-- | lib/esan/CMakeLists.txt | 43 | ||||
-rw-r--r-- | lib/esan/cache_frag.cpp | 208 | ||||
-rw-r--r-- | lib/esan/cache_frag.h | 29 | ||||
-rw-r--r-- | lib/esan/esan.cpp | 270 | ||||
-rw-r--r-- | lib/esan/esan.h | 60 | ||||
-rw-r--r-- | lib/esan/esan.syms.extra | 4 | ||||
-rw-r--r-- | lib/esan/esan_circular_buffer.h | 96 | ||||
-rw-r--r-- | lib/esan/esan_flags.cpp | 58 | ||||
-rw-r--r-- | lib/esan/esan_flags.h | 41 | ||||
-rw-r--r-- | lib/esan/esan_flags.inc | 56 | ||||
-rw-r--r-- | lib/esan/esan_interceptors.cpp | 547 | ||||
-rw-r--r-- | lib/esan/esan_interface.cpp | 122 | ||||
-rw-r--r-- | lib/esan/esan_interface_internal.h | 80 | ||||
-rw-r--r-- | lib/esan/esan_linux.cpp | 83 | ||||
-rw-r--r-- | lib/esan/esan_shadow.h | 203 | ||||
-rw-r--r-- | lib/esan/esan_sideline.h | 61 | ||||
-rw-r--r-- | lib/esan/esan_sideline_linux.cpp | 177 | ||||
-rw-r--r-- | lib/esan/working_set.cpp | 279 | ||||
-rw-r--r-- | lib/esan/working_set.h | 40 | ||||
-rw-r--r-- | lib/esan/working_set_posix.cpp | 133 |
20 files changed, 2590 insertions, 0 deletions
diff --git a/lib/esan/CMakeLists.txt b/lib/esan/CMakeLists.txt new file mode 100644 index 0000000000000..2a0a71b2e3482 --- /dev/null +++ b/lib/esan/CMakeLists.txt @@ -0,0 +1,43 @@ +# Build for the EfficiencySanitizer runtime support library. + +add_custom_target(esan) +set_target_properties(esan PROPERTIES FOLDER "Compiler-RT Misc") + +set(ESAN_RTL_CFLAGS ${SANITIZER_COMMON_CFLAGS}) +append_rtti_flag(OFF ESAN_RTL_CFLAGS) + +include_directories(..) + +set(ESAN_SOURCES + esan.cpp + esan_flags.cpp + esan_interface.cpp + esan_interceptors.cpp + esan_linux.cpp + esan_sideline_linux.cpp + cache_frag.cpp + working_set.cpp + working_set_posix.cpp) + +foreach (arch ${ESAN_SUPPORTED_ARCH}) + add_compiler_rt_runtime(clang_rt.esan + STATIC + ARCHS ${arch} + SOURCES ${ESAN_SOURCES} + $<TARGET_OBJECTS:RTInterception.${arch}> + $<TARGET_OBJECTS:RTSanitizerCommon.${arch}> + $<TARGET_OBJECTS:RTSanitizerCommonLibc.${arch}> + CFLAGS ${ESAN_RTL_CFLAGS}) + add_sanitizer_rt_symbols(clang_rt.esan + ARCHS ${arch} + EXTRA esan.syms.extra) + add_dependencies(esan + clang_rt.esan-${arch} + clang_rt.esan-${arch}-symbols) +endforeach() + +add_dependencies(compiler-rt esan) + +if (COMPILER_RT_INCLUDE_TESTS) + # TODO(bruening): add tests via add_subdirectory(tests) +endif() diff --git a/lib/esan/cache_frag.cpp b/lib/esan/cache_frag.cpp new file mode 100644 index 0000000000000..a3e612daceb1d --- /dev/null +++ b/lib/esan/cache_frag.cpp @@ -0,0 +1,208 @@ +//===-- cache_frag.cpp ----------------------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// This file contains cache fragmentation-specific code. +//===----------------------------------------------------------------------===// + +#include "esan.h" +#include "esan_flags.h" +#include "sanitizer_common/sanitizer_addrhashmap.h" +#include "sanitizer_common/sanitizer_common.h" +#include "sanitizer_common/sanitizer_placement_new.h" +#include <string.h> + +namespace __esan { + +//===-- Struct field access counter runtime -------------------------------===// + +// This should be kept consistent with LLVM's EfficiencySanitizer StructInfo. +struct StructInfo { + const char *StructName; + u32 Size; + u32 NumFields; + u32 *FieldOffset; // auxiliary struct field info. + u32 *FieldSize; // auxiliary struct field info. + const char **FieldTypeName; // auxiliary struct field info. + u64 *FieldCounters; + u64 *ArrayCounter; + bool hasAuxFieldInfo() { return FieldOffset != nullptr; } +}; + +// This should be kept consistent with LLVM's EfficiencySanitizer CacheFragInfo. +// The tool-specific information per compilation unit (module). +struct CacheFragInfo { + const char *UnitName; + u32 NumStructs; + StructInfo *Structs; +}; + +struct StructCounter { + StructInfo *Struct; + u64 Count; // The total access count of the struct. + u64 Ratio; // Difference ratio for the struct layout access. +}; + +// We use StructHashMap to keep track of an unique copy of StructCounter. +typedef AddrHashMap<StructCounter, 31051> StructHashMap; +struct Context { + StructHashMap StructMap; + u32 NumStructs; + u64 TotalCount; // The total access count of all structs. +}; +static Context *Ctx; + +static void reportStructSummary() { + // FIXME: provide a better struct field access summary report. + Report("%s: total struct field access count = %llu\n", SanitizerToolName, + Ctx->TotalCount); +} + +// FIXME: we are still exploring proper ways to evaluate the difference between +// struct field counts. Currently, we use a simple formula to calculate the +// difference ratio: V1/V2. +static inline u64 computeDifferenceRatio(u64 Val1, u64 Val2) { + if (Val2 > Val1) { + Swap(Val1, Val2); + } + if (Val2 == 0) + Val2 = 1; + return (Val1 / Val2); +} + +static void reportStructCounter(StructHashMap::Handle &Handle) { + const u32 TypePrintLimit = 512; + const char *type, *start, *end; + StructInfo *Struct = Handle->Struct; + // Union field address calculation is done via bitcast instead of GEP, + // so the count for union is always 0. + // We skip the union report to avoid confusion. + if (strncmp(Struct->StructName, "union.", 6) == 0) + return; + // Remove the '.' after class/struct during print. + if (strncmp(Struct->StructName, "class.", 6) == 0) { + type = "class"; + start = &Struct->StructName[6]; + } else { + type = "struct"; + start = &Struct->StructName[7]; + } + // Remove the suffixes with '#' during print. + end = strchr(start, '#'); + CHECK(end != nullptr); + Report(" %s %.*s\n", type, end - start, start); + Report(" size = %u, count = %llu, ratio = %llu, array access = %llu\n", + Struct->Size, Handle->Count, Handle->Ratio, *Struct->ArrayCounter); + if (Struct->hasAuxFieldInfo()) { + for (u32 i = 0; i < Struct->NumFields; ++i) { + Report(" #%2u: offset = %u,\t size = %u," + "\t count = %llu,\t type = %.*s\n", + i, Struct->FieldOffset[i], Struct->FieldSize[i], + Struct->FieldCounters[i], TypePrintLimit, Struct->FieldTypeName[i]); + } + } else { + for (u32 i = 0; i < Struct->NumFields; ++i) { + Report(" #%2u: count = %llu\n", i, Struct->FieldCounters[i]); + } + } +} + +static void computeStructRatio(StructHashMap::Handle &Handle) { + Handle->Ratio = 0; + Handle->Count = Handle->Struct->FieldCounters[0]; + for (u32 i = 1; i < Handle->Struct->NumFields; ++i) { + Handle->Count += Handle->Struct->FieldCounters[i]; + Handle->Ratio += computeDifferenceRatio( + Handle->Struct->FieldCounters[i - 1], Handle->Struct->FieldCounters[i]); + } + Ctx->TotalCount += Handle->Count; + if (Handle->Ratio >= (u64)getFlags()->report_threshold || + (Verbosity() >= 1 && Handle->Count > 0)) + reportStructCounter(Handle); +} + +static void registerStructInfo(CacheFragInfo *CacheFrag) { + for (u32 i = 0; i < CacheFrag->NumStructs; ++i) { + StructInfo *Struct = &CacheFrag->Structs[i]; + StructHashMap::Handle H(&Ctx->StructMap, (uptr)Struct->FieldCounters); + if (H.created()) { + VPrintf(2, " Register %s: %u fields\n", Struct->StructName, + Struct->NumFields); + H->Struct = Struct; + ++Ctx->NumStructs; + } else { + VPrintf(2, " Duplicated %s: %u fields\n", Struct->StructName, + Struct->NumFields); + } + } +} + +static void unregisterStructInfo(CacheFragInfo *CacheFrag) { + // FIXME: if the library is unloaded before finalizeCacheFrag, we should + // collect the result for later report. + for (u32 i = 0; i < CacheFrag->NumStructs; ++i) { + StructInfo *Struct = &CacheFrag->Structs[i]; + StructHashMap::Handle H(&Ctx->StructMap, (uptr)Struct->FieldCounters, true); + if (H.exists()) { + VPrintf(2, " Unregister %s: %u fields\n", Struct->StructName, + Struct->NumFields); + // FIXME: we should move this call to finalizeCacheFrag once we can + // iterate over the hash map there. + computeStructRatio(H); + --Ctx->NumStructs; + } else { + VPrintf(2, " Duplicated %s: %u fields\n", Struct->StructName, + Struct->NumFields); + } + } + static bool Reported = false; + if (Ctx->NumStructs == 0 && !Reported) { + Reported = true; + reportStructSummary(); + } +} + +//===-- Init/exit functions -----------------------------------------------===// + +void processCacheFragCompilationUnitInit(void *Ptr) { + CacheFragInfo *CacheFrag = (CacheFragInfo *)Ptr; + VPrintf(2, "in esan::%s: %s with %u class(es)/struct(s)\n", __FUNCTION__, + CacheFrag->UnitName, CacheFrag->NumStructs); + registerStructInfo(CacheFrag); +} + +void processCacheFragCompilationUnitExit(void *Ptr) { + CacheFragInfo *CacheFrag = (CacheFragInfo *)Ptr; + VPrintf(2, "in esan::%s: %s with %u class(es)/struct(s)\n", __FUNCTION__, + CacheFrag->UnitName, CacheFrag->NumStructs); + unregisterStructInfo(CacheFrag); +} + +void initializeCacheFrag() { + VPrintf(2, "in esan::%s\n", __FUNCTION__); + // We use placement new to initialize Ctx before C++ static initializaion. + // We make CtxMem 8-byte aligned for atomic operations in AddrHashMap. + static u64 CtxMem[sizeof(Context) / sizeof(u64) + 1]; + Ctx = new (CtxMem) Context(); + Ctx->NumStructs = 0; +} + +int finalizeCacheFrag() { + VPrintf(2, "in esan::%s\n", __FUNCTION__); + return 0; +} + +void reportCacheFrag() { + VPrintf(2, "in esan::%s\n", __FUNCTION__); + // FIXME: Not yet implemented. We need to iterate over all of the + // compilation unit data. +} + +} // namespace __esan diff --git a/lib/esan/cache_frag.h b/lib/esan/cache_frag.h new file mode 100644 index 0000000000000..646d3f85ed97a --- /dev/null +++ b/lib/esan/cache_frag.h @@ -0,0 +1,29 @@ +//===-- cache_frag.h --------------------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// Header for cache-fragmentation-specific code. +//===----------------------------------------------------------------------===// + +#ifndef CACHE_FRAG_H +#define CACHE_FRAG_H + +namespace __esan { + +void processCacheFragCompilationUnitInit(void *Ptr); +void processCacheFragCompilationUnitExit(void *Ptr); + +void initializeCacheFrag(); +int finalizeCacheFrag(); +void reportCacheFrag(); + +} // namespace __esan + +#endif // CACHE_FRAG_H diff --git a/lib/esan/esan.cpp b/lib/esan/esan.cpp new file mode 100644 index 0000000000000..2fb77894d4fb6 --- /dev/null +++ b/lib/esan/esan.cpp @@ -0,0 +1,270 @@ +//===-- esan.cpp ----------------------------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// Main file (entry points) for the Esan run-time. +//===----------------------------------------------------------------------===// + +#include "esan.h" +#include "esan_flags.h" +#include "esan_interface_internal.h" +#include "esan_shadow.h" +#include "cache_frag.h" +#include "sanitizer_common/sanitizer_common.h" +#include "sanitizer_common/sanitizer_flag_parser.h" +#include "sanitizer_common/sanitizer_flags.h" +#include "working_set.h" + +// See comment below. +extern "C" { +extern void __cxa_atexit(void (*function)(void)); +} + +namespace __esan { + +bool EsanIsInitialized; +bool EsanDuringInit; +ShadowMapping Mapping; + +// Different tools use different scales within the same shadow mapping scheme. +// The scale used here must match that used by the compiler instrumentation. +// This array is indexed by the ToolType enum. +static const uptr ShadowScale[] = { + 0, // ESAN_None. + 2, // ESAN_CacheFrag: 4B:1B, so 4 to 1 == >>2. + 6, // ESAN_WorkingSet: 64B:1B, so 64 to 1 == >>6. +}; + +// We are combining multiple performance tuning tools under the umbrella of +// one EfficiencySanitizer super-tool. Most of our tools have very similar +// memory access instrumentation, shadow memory mapping, libc interception, +// etc., and there is typically more shared code than distinct code. +// +// We are not willing to dispatch on tool dynamically in our fastpath +// instrumentation: thus, which tool to use is a static option selected +// at compile time and passed to __esan_init(). +// +// We are willing to pay the overhead of tool dispatch in the slowpath to more +// easily share code. We expect to only come here rarely. +// If this becomes a performance hit, we can add separate interface +// routines for each subtool (e.g., __esan_cache_frag_aligned_load_4). +// But for libc interceptors, we'll have to do one of the following: +// A) Add multiple-include support to sanitizer_common_interceptors.inc, +// instantiate it separately for each tool, and call the selected +// tool's intercept setup code. +// B) Build separate static runtime libraries, one for each tool. +// C) Completely split the tools into separate sanitizers. + +void processRangeAccess(uptr PC, uptr Addr, int Size, bool IsWrite) { + VPrintf(3, "in esan::%s %p: %c %p %d\n", __FUNCTION__, PC, + IsWrite ? 'w' : 'r', Addr, Size); + if (__esan_which_tool == ESAN_CacheFrag) { + // TODO(bruening): add shadow mapping and update shadow bits here. + // We'll move this to cache_frag.cpp once we have something. + } else if (__esan_which_tool == ESAN_WorkingSet) { + processRangeAccessWorkingSet(PC, Addr, Size, IsWrite); + } +} + +bool processSignal(int SigNum, void (*Handler)(int), void (**Result)(int)) { + if (__esan_which_tool == ESAN_WorkingSet) + return processWorkingSetSignal(SigNum, Handler, Result); + return true; +} + +bool processSigaction(int SigNum, const void *Act, void *OldAct) { + if (__esan_which_tool == ESAN_WorkingSet) + return processWorkingSetSigaction(SigNum, Act, OldAct); + return true; +} + +bool processSigprocmask(int How, void *Set, void *OldSet) { + if (__esan_which_tool == ESAN_WorkingSet) + return processWorkingSetSigprocmask(How, Set, OldSet); + return true; +} + +#if SANITIZER_DEBUG +static bool verifyShadowScheme() { + // Sanity checks for our shadow mapping scheme. + uptr AppStart, AppEnd; + if (Verbosity() >= 3) { + for (int i = 0; getAppRegion(i, &AppStart, &AppEnd); ++i) { + VPrintf(3, "App #%d: [%zx-%zx) (%zuGB)\n", i, AppStart, AppEnd, + (AppEnd - AppStart) >> 30); + } + } + for (int Scale = 0; Scale < 8; ++Scale) { + Mapping.initialize(Scale); + if (Verbosity() >= 3) { + VPrintf(3, "\nChecking scale %d\n", Scale); + uptr ShadowStart, ShadowEnd; + for (int i = 0; getShadowRegion(i, &ShadowStart, &ShadowEnd); ++i) { + VPrintf(3, "Shadow #%d: [%zx-%zx) (%zuGB)\n", i, ShadowStart, + ShadowEnd, (ShadowEnd - ShadowStart) >> 30); + } + for (int i = 0; getShadowRegion(i, &ShadowStart, &ShadowEnd); ++i) { + VPrintf(3, "Shadow(Shadow) #%d: [%zx-%zx)\n", i, + appToShadow(ShadowStart), appToShadow(ShadowEnd - 1)+1); + } + } + for (int i = 0; getAppRegion(i, &AppStart, &AppEnd); ++i) { + DCHECK(isAppMem(AppStart)); + DCHECK(!isAppMem(AppStart - 1)); + DCHECK(isAppMem(AppEnd - 1)); + DCHECK(!isAppMem(AppEnd)); + DCHECK(!isShadowMem(AppStart)); + DCHECK(!isShadowMem(AppEnd - 1)); + DCHECK(isShadowMem(appToShadow(AppStart))); + DCHECK(isShadowMem(appToShadow(AppEnd - 1))); + // Double-shadow checks. + DCHECK(!isShadowMem(appToShadow(appToShadow(AppStart)))); + DCHECK(!isShadowMem(appToShadow(appToShadow(AppEnd - 1)))); + } + // Ensure no shadow regions overlap each other. + uptr ShadowAStart, ShadowBStart, ShadowAEnd, ShadowBEnd; + for (int i = 0; getShadowRegion(i, &ShadowAStart, &ShadowAEnd); ++i) { + for (int j = 0; getShadowRegion(j, &ShadowBStart, &ShadowBEnd); ++j) { + DCHECK(i == j || ShadowAStart >= ShadowBEnd || + ShadowAEnd <= ShadowBStart); + } + } + } + return true; +} +#endif + +static void initializeShadow() { + verifyAddressSpace(); + + DCHECK(verifyShadowScheme()); + + Mapping.initialize(ShadowScale[__esan_which_tool]); + + VPrintf(1, "Shadow scale=%d offset=%p\n", Mapping.Scale, Mapping.Offset); + + uptr ShadowStart, ShadowEnd; + for (int i = 0; getShadowRegion(i, &ShadowStart, &ShadowEnd); ++i) { + VPrintf(1, "Shadow #%d: [%zx-%zx) (%zuGB)\n", i, ShadowStart, ShadowEnd, + (ShadowEnd - ShadowStart) >> 30); + + uptr Map; + if (__esan_which_tool == ESAN_WorkingSet) { + // We want to identify all shadow pages that are touched so we start + // out inaccessible. + Map = (uptr)MmapFixedNoAccess(ShadowStart, ShadowEnd- ShadowStart, + "shadow"); + } else { + Map = (uptr)MmapFixedNoReserve(ShadowStart, ShadowEnd - ShadowStart, + "shadow"); + } + if (Map != ShadowStart) { + Printf("FATAL: EfficiencySanitizer failed to map its shadow memory.\n"); + Die(); + } + + if (common_flags()->no_huge_pages_for_shadow) + NoHugePagesInRegion(ShadowStart, ShadowEnd - ShadowStart); + if (common_flags()->use_madv_dontdump) + DontDumpShadowMemory(ShadowStart, ShadowEnd - ShadowStart); + + // TODO: Call MmapNoAccess() on in-between regions. + } +} + +void initializeLibrary(ToolType Tool) { + // We assume there is only one thread during init, but we need to + // guard against double-init when we're (re-)called from an + // early interceptor. + if (EsanIsInitialized || EsanDuringInit) + return; + EsanDuringInit = true; + CHECK(Tool == __esan_which_tool); + SanitizerToolName = "EfficiencySanitizer"; + CacheBinaryName(); + initializeFlags(); + + // Intercepting libc _exit or exit via COMMON_INTERCEPTOR_ON_EXIT only + // finalizes on an explicit exit call by the app. To handle a normal + // exit we register an atexit handler. + ::__cxa_atexit((void (*)())finalizeLibrary); + + VPrintf(1, "in esan::%s\n", __FUNCTION__); + if (__esan_which_tool <= ESAN_None || __esan_which_tool >= ESAN_Max) { + Printf("ERROR: unknown tool %d requested\n", __esan_which_tool); + Die(); + } + + initializeShadow(); + if (__esan_which_tool == ESAN_WorkingSet) + initializeShadowWorkingSet(); + + initializeInterceptors(); + + if (__esan_which_tool == ESAN_CacheFrag) { + initializeCacheFrag(); + } else if (__esan_which_tool == ESAN_WorkingSet) { + initializeWorkingSet(); + } + + EsanIsInitialized = true; + EsanDuringInit = false; +} + +int finalizeLibrary() { + VPrintf(1, "in esan::%s\n", __FUNCTION__); + if (__esan_which_tool == ESAN_CacheFrag) { + return finalizeCacheFrag(); + } else if (__esan_which_tool == ESAN_WorkingSet) { + return finalizeWorkingSet(); + } + return 0; +} + +void reportResults() { + VPrintf(1, "in esan::%s\n", __FUNCTION__); + if (__esan_which_tool == ESAN_CacheFrag) { + return reportCacheFrag(); + } else if (__esan_which_tool == ESAN_WorkingSet) { + return reportWorkingSet(); + } +} + +void processCompilationUnitInit(void *Ptr) { + VPrintf(2, "in esan::%s\n", __FUNCTION__); + if (__esan_which_tool == ESAN_CacheFrag) { + DCHECK(Ptr != nullptr); + processCacheFragCompilationUnitInit(Ptr); + } else { + DCHECK(Ptr == nullptr); + } +} + +// This is called when the containing module is unloaded. +// For the main executable module, this is called after finalizeLibrary. +void processCompilationUnitExit(void *Ptr) { + VPrintf(2, "in esan::%s\n", __FUNCTION__); + if (__esan_which_tool == ESAN_CacheFrag) { + DCHECK(Ptr != nullptr); + processCacheFragCompilationUnitExit(Ptr); + } else { + DCHECK(Ptr == nullptr); + } +} + +unsigned int getSampleCount() { + VPrintf(1, "in esan::%s\n", __FUNCTION__); + if (__esan_which_tool == ESAN_WorkingSet) { + return getSampleCountWorkingSet(); + } + return 0; +} + +} // namespace __esan diff --git a/lib/esan/esan.h b/lib/esan/esan.h new file mode 100644 index 0000000000000..5a0dde627888f --- /dev/null +++ b/lib/esan/esan.h @@ -0,0 +1,60 @@ +//===-- esan.h --------------------------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// Main internal esan header file. +// +// Ground rules: +// - C++ run-time should not be used (static CTORs, RTTI, exceptions, static +// function-scope locals) +// - All functions/classes/etc reside in namespace __esan, except for those +// declared in esan_interface_internal.h. +// - Platform-specific files should be used instead of ifdefs (*). +// - No system headers included in header files (*). +// - Platform specific headers included only into platform-specific files (*). +// +// (*) Except when inlining is critical for performance. +//===----------------------------------------------------------------------===// + +#ifndef ESAN_H +#define ESAN_H + +#include "interception/interception.h" +#include "sanitizer_common/sanitizer_common.h" +#include "esan_interface_internal.h" + +namespace __esan { + +extern bool EsanIsInitialized; +extern bool EsanDuringInit; + +void initializeLibrary(ToolType Tool); +int finalizeLibrary(); +void reportResults(); +unsigned int getSampleCount(); +// Esan creates the variable per tool per compilation unit at compile time +// and passes its pointer Ptr to the runtime library. +void processCompilationUnitInit(void *Ptr); +void processCompilationUnitExit(void *Ptr); +void processRangeAccess(uptr PC, uptr Addr, int Size, bool IsWrite); +void initializeInterceptors(); + +// Platform-dependent routines. +void verifyAddressSpace(); +bool fixMmapAddr(void **Addr, SIZE_T Size, int Flags); +uptr checkMmapResult(uptr Addr, SIZE_T Size); +// The return value indicates whether to call the real version or not. +bool processSignal(int SigNum, void (*Handler)(int), void (**Result)(int)); +bool processSigaction(int SigNum, const void *Act, void *OldAct); +bool processSigprocmask(int How, void *Set, void *OldSet); + +} // namespace __esan + +#endif // ESAN_H diff --git a/lib/esan/esan.syms.extra b/lib/esan/esan.syms.extra new file mode 100644 index 0000000000000..d6397d4c350ff --- /dev/null +++ b/lib/esan/esan.syms.extra @@ -0,0 +1,4 @@ +__esan_init +__esan_exit +__esan_aligned* +__esan_unaligned* diff --git a/lib/esan/esan_circular_buffer.h b/lib/esan/esan_circular_buffer.h new file mode 100644 index 0000000000000..9ce102d04d8f9 --- /dev/null +++ b/lib/esan/esan_circular_buffer.h @@ -0,0 +1,96 @@ +//===-- esan_circular_buffer.h ----------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// Circular buffer data structure. +//===----------------------------------------------------------------------===// + +#include "sanitizer_common/sanitizer_common.h" + +namespace __esan { + +// A circular buffer for POD data whose memory is allocated using mmap. +// There are two usage models: one is to use initialize/free (for global +// instances) and the other is to use placement new with the +// constructor and to call the destructor or free (they are equivalent). +template<typename T> +class CircularBuffer { + public: + // To support global instances we cannot initialize any field in the + // default constructor. + explicit CircularBuffer() {} + CircularBuffer(uptr BufferCapacity) { + initialize(BufferCapacity); + WasConstructed = true; + } + ~CircularBuffer() { + if (WasConstructed) // Else caller will call free() explicitly. + free(); + } + void initialize(uptr BufferCapacity) { + Capacity = BufferCapacity; + // MmapOrDie rounds up to the page size for us. + Data = (T *)MmapOrDie(Capacity * sizeof(T), "CircularBuffer"); + StartIdx = 0; + Count = 0; + WasConstructed = false; + } + void free() { + UnmapOrDie(Data, Capacity * sizeof(T)); + } + T &operator[](uptr Idx) { + CHECK_LT(Idx, Count); + uptr ArrayIdx = (StartIdx + Idx) % Capacity; + return Data[ArrayIdx]; + } + const T &operator[](uptr Idx) const { + CHECK_LT(Idx, Count); + uptr ArrayIdx = (StartIdx + Idx) % Capacity; + return Data[ArrayIdx]; + } + void push_back(const T &Item) { + CHECK_GT(Capacity, 0); + uptr ArrayIdx = (StartIdx + Count) % Capacity; + Data[ArrayIdx] = Item; + if (Count < Capacity) + ++Count; + else + StartIdx = (StartIdx + 1) % Capacity; + } + T &back() { + CHECK_GT(Count, 0); + uptr ArrayIdx = (StartIdx + Count - 1) % Capacity; + return Data[ArrayIdx]; + } + void pop_back() { + CHECK_GT(Count, 0); + --Count; + } + uptr size() const { + return Count; + } + void clear() { + StartIdx = 0; + Count = 0; + } + bool empty() const { return size() == 0; } + + private: + CircularBuffer(const CircularBuffer&); + void operator=(const CircularBuffer&); + + bool WasConstructed; + T *Data; + uptr Capacity; + uptr StartIdx; + uptr Count; +}; + +} // namespace __esan diff --git a/lib/esan/esan_flags.cpp b/lib/esan/esan_flags.cpp new file mode 100644 index 0000000000000..3b047e28be225 --- /dev/null +++ b/lib/esan/esan_flags.cpp @@ -0,0 +1,58 @@ +//===-- esan_flags.cc -------------------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// Esan flag parsing logic. +//===----------------------------------------------------------------------===// + +#include "esan_flags.h" +#include "sanitizer_common/sanitizer_common.h" +#include "sanitizer_common/sanitizer_flag_parser.h" +#include "sanitizer_common/sanitizer_flags.h" + +namespace __esan { + +static const char EsanOptsEnv[] = "ESAN_OPTIONS"; + +Flags EsanFlagsDontUseDirectly; + +void Flags::setDefaults() { +#define ESAN_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue; +#include "esan_flags.inc" +#undef ESAN_FLAG +} + +static void registerEsanFlags(FlagParser *Parser, Flags *F) { +#define ESAN_FLAG(Type, Name, DefaultValue, Description) \ + RegisterFlag(Parser, #Name, Description, &F->Name); +#include "esan_flags.inc" +#undef ESAN_FLAG +} + +void initializeFlags() { + SetCommonFlagsDefaults(); + Flags *F = getFlags(); + F->setDefaults(); + + FlagParser Parser; + registerEsanFlags(&Parser, F); + RegisterCommonFlags(&Parser); + Parser.ParseString(GetEnv(EsanOptsEnv)); + + InitializeCommonFlags(); + if (Verbosity()) + ReportUnrecognizedFlags(); + if (common_flags()->help) + Parser.PrintFlagDescriptions(); + + __sanitizer_set_report_path(common_flags()->log_path); +} + +} // namespace __esan diff --git a/lib/esan/esan_flags.h b/lib/esan/esan_flags.h new file mode 100644 index 0000000000000..c8f4ef5ab2b57 --- /dev/null +++ b/lib/esan/esan_flags.h @@ -0,0 +1,41 @@ +//===-- esan_flags.h --------------------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// Esan runtime flags. +//===----------------------------------------------------------------------===// + +#ifndef ESAN_FLAGS_H +#define ESAN_FLAGS_H + +#include "sanitizer_common/sanitizer_internal_defs.h" +#include "sanitizer_common/sanitizer_flag_parser.h" + +namespace __esan { + +class Flags { +public: +#define ESAN_FLAG(Type, Name, DefaultValue, Description) Type Name; +#include "esan_flags.inc" +#undef ESAN_FLAG + + void setDefaults(); +}; + +extern Flags EsanFlagsDontUseDirectly; +inline Flags *getFlags() { + return &EsanFlagsDontUseDirectly; +} + +void initializeFlags(); + +} // namespace __esan + +#endif // ESAN_FLAGS_H diff --git a/lib/esan/esan_flags.inc b/lib/esan/esan_flags.inc new file mode 100644 index 0000000000000..5687caca29892 --- /dev/null +++ b/lib/esan/esan_flags.inc @@ -0,0 +1,56 @@ +//===-- esan_flags.inc ------------------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// Esan runtime flags. +// +//===----------------------------------------------------------------------===// + +#ifndef ESAN_FLAG +# error "Define ESAN_FLAG prior to including this file!" +#endif + +// ESAN_FLAG(Type, Name, DefaultValue, Description) +// See COMMON_FLAG in sanitizer_flags.inc for more details. + +//===----------------------------------------------------------------------===// +// Cross-tool options +//===----------------------------------------------------------------------===// + +ESAN_FLAG(int, cache_line_size, 64, + "The number of bytes in a cache line. For the working-set tool, this " + "cannot be changed without also changing the compiler " + "instrumentation.") + +//===----------------------------------------------------------------------===// +// Working set tool options +//===----------------------------------------------------------------------===// + +ESAN_FLAG(bool, record_snapshots, true, + "Working set tool: whether to sample snapshots during a run.") + +// Typical profiling uses a 10ms timer. Our snapshots take some work +// to scan memory so we reduce to 20ms. +// To disable samples, turn off record_snapshots. +ESAN_FLAG(int, sample_freq, 20, + "Working set tool: sampling frequency in milliseconds.") + +// This controls the difference in frequency between each successive series +// of snapshots. There are 8 in total, with number 0 using sample_freq. +// Number N samples number N-1 every (1 << snapshot_step) instance of N-1. +ESAN_FLAG(int, snapshot_step, 2, "Working set tool: the log of the sampling " + "performed for the next-higher-frequency snapshot series.") + +//===----------------------------------------------------------------------===// +// Cache Fragmentation tool options +//===----------------------------------------------------------------------===// + +// The difference information of a struct is reported if the struct's difference +// score is greater than the report_threshold. +ESAN_FLAG(int, report_threshold, 1<<10, "Cache-frag tool: the struct difference" + " score threshold for reporting.") diff --git a/lib/esan/esan_interceptors.cpp b/lib/esan/esan_interceptors.cpp new file mode 100644 index 0000000000000..647f010852b09 --- /dev/null +++ b/lib/esan/esan_interceptors.cpp @@ -0,0 +1,547 @@ +//===-- esan_interceptors.cpp ---------------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// Interception routines for the esan run-time. +//===----------------------------------------------------------------------===// + +#include "esan.h" +#include "esan_shadow.h" +#include "interception/interception.h" +#include "sanitizer_common/sanitizer_common.h" +#include "sanitizer_common/sanitizer_libc.h" +#include "sanitizer_common/sanitizer_linux.h" +#include "sanitizer_common/sanitizer_stacktrace.h" + +using namespace __esan; // NOLINT + +#define CUR_PC() (StackTrace::GetCurrentPc()) + +//===----------------------------------------------------------------------===// +// Interception via sanitizer common interceptors +//===----------------------------------------------------------------------===// + +// Get the per-platform defines for what is possible to intercept +#include "sanitizer_common/sanitizer_platform_interceptors.h" + +// TODO(bruening): tsan disables several interceptors (getpwent, etc.) claiming +// that interception is a perf hit: should we do the same? + +// We have no need to intercept: +#undef SANITIZER_INTERCEPT_TLS_GET_ADDR + +// TODO(bruening): the common realpath interceptor assumes malloc is +// intercepted! We should try to parametrize that, though we'll +// intercept malloc soon ourselves and can then remove this undef. +#undef SANITIZER_INTERCEPT_REALPATH + +// We provide our own version: +#undef SANITIZER_INTERCEPT_SIGPROCMASK + +#define COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED (!EsanIsInitialized) + +#define COMMON_INTERCEPT_FUNCTION(name) INTERCEPT_FUNCTION(name) +#define COMMON_INTERCEPT_FUNCTION_VER(name, ver) \ + INTERCEPT_FUNCTION_VER(name, ver) + +// We must initialize during early interceptors, to support tcmalloc. +// This means that for some apps we fully initialize prior to +// __esan_init() being called. +// We currently do not use ctx. +#define COMMON_INTERCEPTOR_ENTER(ctx, func, ...) \ + do { \ + if (UNLIKELY(COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED)) { \ + if (!UNLIKELY(EsanDuringInit)) \ + initializeLibrary(__esan_which_tool); \ + return REAL(func)(__VA_ARGS__); \ + } \ + ctx = nullptr; \ + (void)ctx; \ + } while (false) + +#define COMMON_INTERCEPTOR_ENTER_NOIGNORE(ctx, func, ...) \ + COMMON_INTERCEPTOR_ENTER(ctx, func, __VA_ARGS__) + +#define COMMON_INTERCEPTOR_WRITE_RANGE(ctx, ptr, size) \ + processRangeAccess(CUR_PC(), (uptr)ptr, size, true) + +#define COMMON_INTERCEPTOR_READ_RANGE(ctx, ptr, size) \ + processRangeAccess(CUR_PC(), (uptr)ptr, size, false) + +// This is only called if the app explicitly calls exit(), not on +// a normal exit. +#define COMMON_INTERCEPTOR_ON_EXIT(ctx) finalizeLibrary() + +#define COMMON_INTERCEPTOR_FILE_OPEN(ctx, file, path) \ + do { \ + (void)(ctx); \ + (void)(file); \ + (void)(path); \ + } while (false) +#define COMMON_INTERCEPTOR_FILE_CLOSE(ctx, file) \ + do { \ + (void)(ctx); \ + (void)(file); \ + } while (false) +#define COMMON_INTERCEPTOR_LIBRARY_LOADED(filename, handle) \ + do { \ + (void)(filename); \ + (void)(handle); \ + } while (false) +#define COMMON_INTERCEPTOR_LIBRARY_UNLOADED() \ + do { \ + } while (false) +#define COMMON_INTERCEPTOR_ACQUIRE(ctx, u) \ + do { \ + (void)(ctx); \ + (void)(u); \ + } while (false) +#define COMMON_INTERCEPTOR_RELEASE(ctx, u) \ + do { \ + (void)(ctx); \ + (void)(u); \ + } while (false) +#define COMMON_INTERCEPTOR_DIR_ACQUIRE(ctx, path) \ + do { \ + (void)(ctx); \ + (void)(path); \ + } while (false) +#define COMMON_INTERCEPTOR_FD_ACQUIRE(ctx, fd) \ + do { \ + (void)(ctx); \ + (void)(fd); \ + } while (false) +#define COMMON_INTERCEPTOR_FD_RELEASE(ctx, fd) \ + do { \ + (void)(ctx); \ + (void)(fd); \ + } while (false) +#define COMMON_INTERCEPTOR_FD_ACCESS(ctx, fd) \ + do { \ + (void)(ctx); \ + (void)(fd); \ + } while (false) +#define COMMON_INTERCEPTOR_FD_SOCKET_ACCEPT(ctx, fd, newfd) \ + do { \ + (void)(ctx); \ + (void)(fd); \ + (void)(newfd); \ + } while (false) +#define COMMON_INTERCEPTOR_SET_THREAD_NAME(ctx, name) \ + do { \ + (void)(ctx); \ + (void)(name); \ + } while (false) +#define COMMON_INTERCEPTOR_SET_PTHREAD_NAME(ctx, thread, name) \ + do { \ + (void)(ctx); \ + (void)(thread); \ + (void)(name); \ + } while (false) +#define COMMON_INTERCEPTOR_BLOCK_REAL(name) REAL(name) +#define COMMON_INTERCEPTOR_MUTEX_LOCK(ctx, m) \ + do { \ + (void)(ctx); \ + (void)(m); \ + } while (false) +#define COMMON_INTERCEPTOR_MUTEX_UNLOCK(ctx, m) \ + do { \ + (void)(ctx); \ + (void)(m); \ + } while (false) +#define COMMON_INTERCEPTOR_MUTEX_REPAIR(ctx, m) \ + do { \ + (void)(ctx); \ + (void)(m); \ + } while (false) +#define COMMON_INTERCEPTOR_HANDLE_RECVMSG(ctx, msg) \ + do { \ + (void)(ctx); \ + (void)(msg); \ + } while (false) +#define COMMON_INTERCEPTOR_USER_CALLBACK_START() \ + do { \ + } while (false) +#define COMMON_INTERCEPTOR_USER_CALLBACK_END() \ + do { \ + } while (false) + +#include "sanitizer_common/sanitizer_common_interceptors.inc" + +//===----------------------------------------------------------------------===// +// Syscall interception +//===----------------------------------------------------------------------===// + +// We want the caller's PC b/c unlike the other function interceptors these +// are separate pre and post functions called around the app's syscall(). + +#define COMMON_SYSCALL_PRE_READ_RANGE(ptr, size) \ + processRangeAccess(GET_CALLER_PC(), (uptr)ptr, size, false) + +#define COMMON_SYSCALL_PRE_WRITE_RANGE(ptr, size) \ + do { \ + (void)(ptr); \ + (void)(size); \ + } while (false) + +#define COMMON_SYSCALL_POST_READ_RANGE(ptr, size) \ + do { \ + (void)(ptr); \ + (void)(size); \ + } while (false) + +// The actual amount written is in post, not pre. +#define COMMON_SYSCALL_POST_WRITE_RANGE(ptr, size) \ + processRangeAccess(GET_CALLER_PC(), (uptr)ptr, size, true) + +#define COMMON_SYSCALL_ACQUIRE(addr) \ + do { \ + (void)(addr); \ + } while (false) +#define COMMON_SYSCALL_RELEASE(addr) \ + do { \ + (void)(addr); \ + } while (false) +#define COMMON_SYSCALL_FD_CLOSE(fd) \ + do { \ + (void)(fd); \ + } while (false) +#define COMMON_SYSCALL_FD_ACQUIRE(fd) \ + do { \ + (void)(fd); \ + } while (false) +#define COMMON_SYSCALL_FD_RELEASE(fd) \ + do { \ + (void)(fd); \ + } while (false) +#define COMMON_SYSCALL_PRE_FORK() \ + do { \ + } while (false) +#define COMMON_SYSCALL_POST_FORK(res) \ + do { \ + (void)(res); \ + } while (false) + +#include "sanitizer_common/sanitizer_common_syscalls.inc" + +//===----------------------------------------------------------------------===// +// Custom interceptors +//===----------------------------------------------------------------------===// + +// TODO(bruening): move more of these to the common interception pool as they +// are shared with tsan and asan. +// While our other files match LLVM style, here we match sanitizer style as we +// expect to move these to the common pool. + +INTERCEPTOR(char *, strcpy, char *dst, const char *src) { // NOLINT + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, strcpy, dst, src); + uptr srclen = internal_strlen(src); + COMMON_INTERCEPTOR_WRITE_RANGE(ctx, dst, srclen + 1); + COMMON_INTERCEPTOR_READ_RANGE(ctx, src, srclen + 1); + return REAL(strcpy)(dst, src); // NOLINT +} + +INTERCEPTOR(char *, strncpy, char *dst, char *src, uptr n) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, strncpy, dst, src, n); + uptr srclen = internal_strnlen(src, n); + uptr copied_size = srclen + 1 > n ? n : srclen + 1; + COMMON_INTERCEPTOR_WRITE_RANGE(ctx, dst, copied_size); + COMMON_INTERCEPTOR_READ_RANGE(ctx, src, copied_size); + return REAL(strncpy)(dst, src, n); +} + +INTERCEPTOR(int, open, const char *name, int flags, int mode) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, open, name, flags, mode); + COMMON_INTERCEPTOR_READ_STRING(ctx, name, 0); + return REAL(open)(name, flags, mode); +} + +#if SANITIZER_LINUX +INTERCEPTOR(int, open64, const char *name, int flags, int mode) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, open64, name, flags, mode); + COMMON_INTERCEPTOR_READ_STRING(ctx, name, 0); + return REAL(open64)(name, flags, mode); +} +#define ESAN_MAYBE_INTERCEPT_OPEN64 INTERCEPT_FUNCTION(open64) +#else +#define ESAN_MAYBE_INTERCEPT_OPEN64 +#endif + +INTERCEPTOR(int, creat, const char *name, int mode) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, creat, name, mode); + COMMON_INTERCEPTOR_READ_STRING(ctx, name, 0); + return REAL(creat)(name, mode); +} + +#if SANITIZER_LINUX +INTERCEPTOR(int, creat64, const char *name, int mode) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, creat64, name, mode); + COMMON_INTERCEPTOR_READ_STRING(ctx, name, 0); + return REAL(creat64)(name, mode); +} +#define ESAN_MAYBE_INTERCEPT_CREAT64 INTERCEPT_FUNCTION(creat64) +#else +#define ESAN_MAYBE_INTERCEPT_CREAT64 +#endif + +INTERCEPTOR(int, unlink, char *path) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, unlink, path); + COMMON_INTERCEPTOR_READ_STRING(ctx, path, 0); + return REAL(unlink)(path); +} + +INTERCEPTOR(uptr, fread, void *ptr, uptr size, uptr nmemb, void *f) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, fread, ptr, size, nmemb, f); + COMMON_INTERCEPTOR_WRITE_RANGE(ctx, ptr, size * nmemb); + return REAL(fread)(ptr, size, nmemb, f); +} + +INTERCEPTOR(uptr, fwrite, const void *p, uptr size, uptr nmemb, void *f) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, fwrite, p, size, nmemb, f); + COMMON_INTERCEPTOR_READ_RANGE(ctx, p, size * nmemb); + return REAL(fwrite)(p, size, nmemb, f); +} + +INTERCEPTOR(int, puts, const char *s) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, puts, s); + COMMON_INTERCEPTOR_READ_RANGE(ctx, s, internal_strlen(s)); + return REAL(puts)(s); +} + +INTERCEPTOR(int, rmdir, char *path) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, rmdir, path); + COMMON_INTERCEPTOR_READ_STRING(ctx, path, 0); + return REAL(rmdir)(path); +} + +//===----------------------------------------------------------------------===// +// Shadow-related interceptors +//===----------------------------------------------------------------------===// + +// These are candidates for sharing with all sanitizers if shadow memory +// support is also standardized. + +INTERCEPTOR(void *, mmap, void *addr, SIZE_T sz, int prot, int flags, + int fd, OFF_T off) { + if (UNLIKELY(REAL(mmap) == nullptr)) { + // With esan init during interceptor init and a static libc preventing + // our early-calloc from triggering, we can end up here before our + // REAL pointer is set up. + return (void *)internal_mmap(addr, sz, prot, flags, fd, off); + } + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, mmap, addr, sz, prot, flags, fd, off); + if (!fixMmapAddr(&addr, sz, flags)) + return (void *)-1; + void *result = REAL(mmap)(addr, sz, prot, flags, fd, off); + return (void *)checkMmapResult((uptr)result, sz); +} + +#if SANITIZER_LINUX +INTERCEPTOR(void *, mmap64, void *addr, SIZE_T sz, int prot, int flags, + int fd, OFF64_T off) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, mmap64, addr, sz, prot, flags, fd, off); + if (!fixMmapAddr(&addr, sz, flags)) + return (void *)-1; + void *result = REAL(mmap64)(addr, sz, prot, flags, fd, off); + return (void *)checkMmapResult((uptr)result, sz); +} +#define ESAN_MAYBE_INTERCEPT_MMAP64 INTERCEPT_FUNCTION(mmap64) +#else +#define ESAN_MAYBE_INTERCEPT_MMAP64 +#endif + +//===----------------------------------------------------------------------===// +// Signal-related interceptors +//===----------------------------------------------------------------------===// + +#if SANITIZER_LINUX +typedef void (*signal_handler_t)(int); +INTERCEPTOR(signal_handler_t, signal, int signum, signal_handler_t handler) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, signal, signum, handler); + signal_handler_t result; + if (!processSignal(signum, handler, &result)) + return result; + else + return REAL(signal)(signum, handler); +} +#define ESAN_MAYBE_INTERCEPT_SIGNAL INTERCEPT_FUNCTION(signal) +#else +#error Platform not supported +#define ESAN_MAYBE_INTERCEPT_SIGNAL +#endif + +#if SANITIZER_LINUX +DECLARE_REAL(int, sigaction, int signum, const struct sigaction *act, + struct sigaction *oldact) +INTERCEPTOR(int, sigaction, int signum, const struct sigaction *act, + struct sigaction *oldact) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, sigaction, signum, act, oldact); + if (!processSigaction(signum, act, oldact)) + return 0; + else + return REAL(sigaction)(signum, act, oldact); +} + +// This is required to properly use internal_sigaction. +namespace __sanitizer { +int real_sigaction(int signum, const void *act, void *oldact) { + if (REAL(sigaction) == nullptr) { + // With an instrumented allocator, this is called during interceptor init + // and we need a raw syscall solution. + return internal_sigaction_syscall(signum, act, oldact); + } + return REAL(sigaction)(signum, (const struct sigaction *)act, + (struct sigaction *)oldact); +} +} // namespace __sanitizer + +#define ESAN_MAYBE_INTERCEPT_SIGACTION INTERCEPT_FUNCTION(sigaction) +#else +#error Platform not supported +#define ESAN_MAYBE_INTERCEPT_SIGACTION +#endif + +#if SANITIZER_LINUX +INTERCEPTOR(int, sigprocmask, int how, __sanitizer_sigset_t *set, + __sanitizer_sigset_t *oldset) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, sigprocmask, how, set, oldset); + int res = 0; + if (processSigprocmask(how, set, oldset)) + res = REAL(sigprocmask)(how, set, oldset); + if (!res && oldset) + COMMON_INTERCEPTOR_WRITE_RANGE(ctx, oldset, sizeof(*oldset)); + return res; +} +#define ESAN_MAYBE_INTERCEPT_SIGPROCMASK INTERCEPT_FUNCTION(sigprocmask) +#else +#define ESAN_MAYBE_INTERCEPT_SIGPROCMASK +#endif + +#if !SANITIZER_WINDOWS +INTERCEPTOR(int, pthread_sigmask, int how, __sanitizer_sigset_t *set, + __sanitizer_sigset_t *oldset) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, pthread_sigmask, how, set, oldset); + int res = 0; + if (processSigprocmask(how, set, oldset)) + res = REAL(sigprocmask)(how, set, oldset); + if (!res && oldset) + COMMON_INTERCEPTOR_WRITE_RANGE(ctx, oldset, sizeof(*oldset)); + return res; +} +#define ESAN_MAYBE_INTERCEPT_PTHREAD_SIGMASK INTERCEPT_FUNCTION(pthread_sigmask) +#else +#define ESAN_MAYBE_INTERCEPT_PTHREAD_SIGMASK +#endif + +//===----------------------------------------------------------------------===// +// Malloc interceptors +//===----------------------------------------------------------------------===// + +static char early_alloc_buf[128]; +static bool used_early_alloc_buf; + +static void *handleEarlyAlloc(uptr size) { + // If esan is initialized during an interceptor (which happens with some + // tcmalloc implementations that call pthread_mutex_lock), the call from + // dlsym to calloc will deadlock. There is only one such calloc (dlsym + // allocates a single pthread key), so we work around it by using a + // static buffer for the calloc request. The loader currently needs + // 32 bytes but we size at 128 to allow for future changes. + // This solution will also allow us to deliberately intercept malloc & family + // in the future (to perform tool actions on each allocation, without + // replacing the allocator), as it also solves the problem of intercepting + // calloc when it will itself be called before its REAL pointer is + // initialized. + CHECK(!used_early_alloc_buf && size < sizeof(early_alloc_buf)); + // We do not handle multiple threads here. This only happens at process init + // time, and while it's possible for a shared library to create early threads + // that race here, we consider that to be a corner case extreme enough that + // it's not worth the effort to handle. + used_early_alloc_buf = true; + return (void *)early_alloc_buf; +} + +INTERCEPTOR(void*, calloc, uptr size, uptr n) { + if (EsanDuringInit && REAL(calloc) == nullptr) + return handleEarlyAlloc(size * n); + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, calloc, size, n); + void *res = REAL(calloc)(size, n); + // The memory is zeroed and thus is all written. + COMMON_INTERCEPTOR_WRITE_RANGE(nullptr, (uptr)res, size * n); + return res; +} + +INTERCEPTOR(void, free, void *p) { + void *ctx; + COMMON_INTERCEPTOR_ENTER(ctx, free, p); + if (p == (void *)early_alloc_buf) { + // We expect just a singleton use but we clear this for cleanliness. + used_early_alloc_buf = false; + return; + } + REAL(free)(p); +} + +namespace __esan { + +void initializeInterceptors() { + InitializeCommonInterceptors(); + + INTERCEPT_FUNCTION(strcpy); // NOLINT + INTERCEPT_FUNCTION(strncpy); + + INTERCEPT_FUNCTION(open); + ESAN_MAYBE_INTERCEPT_OPEN64; + INTERCEPT_FUNCTION(creat); + ESAN_MAYBE_INTERCEPT_CREAT64; + INTERCEPT_FUNCTION(unlink); + INTERCEPT_FUNCTION(fread); + INTERCEPT_FUNCTION(fwrite); + INTERCEPT_FUNCTION(puts); + INTERCEPT_FUNCTION(rmdir); + + INTERCEPT_FUNCTION(mmap); + ESAN_MAYBE_INTERCEPT_MMAP64; + + ESAN_MAYBE_INTERCEPT_SIGNAL; + ESAN_MAYBE_INTERCEPT_SIGACTION; + ESAN_MAYBE_INTERCEPT_SIGPROCMASK; + ESAN_MAYBE_INTERCEPT_PTHREAD_SIGMASK; + + INTERCEPT_FUNCTION(calloc); + INTERCEPT_FUNCTION(free); + + // TODO(bruening): intercept routines that other sanitizers intercept that + // are not in the common pool or here yet, ideally by adding to the common + // pool. Examples include wcslen and bcopy. + + // TODO(bruening): there are many more libc routines that read or write data + // structures that no sanitizer is intercepting: sigaction, strtol, etc. +} + +} // namespace __esan diff --git a/lib/esan/esan_interface.cpp b/lib/esan/esan_interface.cpp new file mode 100644 index 0000000000000..43b3dff86f778 --- /dev/null +++ b/lib/esan/esan_interface.cpp @@ -0,0 +1,122 @@ +//===-- esan_interface.cpp ------------------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +//===----------------------------------------------------------------------===// + +#include "esan_interface_internal.h" +#include "esan.h" +#include "sanitizer_common/sanitizer_internal_defs.h" + +using namespace __esan; // NOLINT + +void __esan_init(ToolType Tool, void *Ptr) { + if (Tool != __esan_which_tool) { + Printf("ERROR: tool mismatch: %d vs %d\n", Tool, __esan_which_tool); + Die(); + } + initializeLibrary(Tool); + processCompilationUnitInit(Ptr); +} + +void __esan_exit(void *Ptr) { + processCompilationUnitExit(Ptr); +} + +void __esan_aligned_load1(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 1, false); +} + +void __esan_aligned_load2(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 2, false); +} + +void __esan_aligned_load4(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 4, false); +} + +void __esan_aligned_load8(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 8, false); +} + +void __esan_aligned_load16(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 16, false); +} + +void __esan_aligned_store1(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 1, true); +} + +void __esan_aligned_store2(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 2, true); +} + +void __esan_aligned_store4(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 4, true); +} + +void __esan_aligned_store8(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 8, true); +} + +void __esan_aligned_store16(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 16, true); +} + +void __esan_unaligned_load2(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 2, false); +} + +void __esan_unaligned_load4(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 4, false); +} + +void __esan_unaligned_load8(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 8, false); +} + +void __esan_unaligned_load16(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 16, false); +} + +void __esan_unaligned_store2(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 2, true); +} + +void __esan_unaligned_store4(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 4, true); +} + +void __esan_unaligned_store8(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 8, true); +} + +void __esan_unaligned_store16(void *Addr) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, 16, true); +} + +void __esan_unaligned_loadN(void *Addr, uptr Size) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, Size, false); +} + +void __esan_unaligned_storeN(void *Addr, uptr Size) { + processRangeAccess(GET_CALLER_PC(), (uptr)Addr, Size, true); +} + +// Public interface: +extern "C" { +SANITIZER_INTERFACE_ATTRIBUTE void __esan_report() { + reportResults(); +} + +SANITIZER_INTERFACE_ATTRIBUTE unsigned int __esan_get_sample_count() { + return getSampleCount(); +} +} // extern "C" diff --git a/lib/esan/esan_interface_internal.h b/lib/esan/esan_interface_internal.h new file mode 100644 index 0000000000000..3b915d03e07a8 --- /dev/null +++ b/lib/esan/esan_interface_internal.h @@ -0,0 +1,80 @@ +//===-- esan_interface_internal.h -------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// Calls to the functions declared in this header will be inserted by +// the instrumentation module. +//===----------------------------------------------------------------------===// + +#ifndef ESAN_INTERFACE_INTERNAL_H +#define ESAN_INTERFACE_INTERNAL_H + +#include <sanitizer_common/sanitizer_internal_defs.h> + +// This header should NOT include any other headers. +// All functions in this header are extern "C" and start with __esan_. + +extern "C" { + +// This should be kept consistent with LLVM's EfficiencySanitizerOptions. +// The value is passed as a 32-bit integer by the compiler. +typedef enum Type : u32 { + ESAN_None = 0, + ESAN_CacheFrag, + ESAN_WorkingSet, + ESAN_Max, +} ToolType; + +// To handle interceptors that invoke instrumented code prior to +// __esan_init() being called, the instrumentation module creates this +// global variable specifying the tool. +extern ToolType __esan_which_tool; + +// This function should be called at the very beginning of the process, +// before any instrumented code is executed and before any call to malloc. +SANITIZER_INTERFACE_ATTRIBUTE void __esan_init(ToolType Tool, void *Ptr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_exit(void *Ptr); + +// The instrumentation module will insert a call to one of these routines prior +// to each load and store instruction for which we do not have "fastpath" +// inlined instrumentation. These calls constitute the "slowpath" for our +// tools. We have separate routines for each type of memory access to enable +// targeted optimization. +SANITIZER_INTERFACE_ATTRIBUTE void __esan_aligned_load1(void *Addr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_aligned_load2(void *Addr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_aligned_load4(void *Addr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_aligned_load8(void *Addr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_aligned_load16(void *Addr); + +SANITIZER_INTERFACE_ATTRIBUTE void __esan_aligned_store1(void *Addr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_aligned_store2(void *Addr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_aligned_store4(void *Addr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_aligned_store8(void *Addr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_aligned_store16(void *Addr); + +SANITIZER_INTERFACE_ATTRIBUTE void __esan_unaligned_load2(void *Addr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_unaligned_load4(void *Addr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_unaligned_load8(void *Addr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_unaligned_load16(void *Addr); + +SANITIZER_INTERFACE_ATTRIBUTE void __esan_unaligned_store2(void *Addr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_unaligned_store4(void *Addr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_unaligned_store8(void *Addr); +SANITIZER_INTERFACE_ATTRIBUTE void __esan_unaligned_store16(void *Addr); + +// These cover unusually-sized accesses. +SANITIZER_INTERFACE_ATTRIBUTE +void __esan_unaligned_loadN(void *Addr, uptr Size); +SANITIZER_INTERFACE_ATTRIBUTE +void __esan_unaligned_storeN(void *Addr, uptr Size); + +} // extern "C" + +#endif // ESAN_INTERFACE_INTERNAL_H diff --git a/lib/esan/esan_linux.cpp b/lib/esan/esan_linux.cpp new file mode 100644 index 0000000000000..aa961b66116bd --- /dev/null +++ b/lib/esan/esan_linux.cpp @@ -0,0 +1,83 @@ +//===-- esan.cpp ----------------------------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// Linux-specific code for the Esan run-time. +//===----------------------------------------------------------------------===// + +#include "sanitizer_common/sanitizer_platform.h" +#if SANITIZER_FREEBSD || SANITIZER_LINUX + +#include "esan.h" +#include "esan_shadow.h" +#include "interception/interception.h" +#include "sanitizer_common/sanitizer_common.h" +#include <sys/mman.h> +#include <errno.h> + +namespace __esan { + +void verifyAddressSpace() { +#if SANITIZER_LINUX && defined(__x86_64__) + // The kernel determines its mmap base from the stack size limit. + // Our Linux 64-bit shadow mapping assumes the stack limit is less than a + // terabyte, which keeps the mmap region above 0x7e00'. + uptr StackLimit = GetStackSizeLimitInBytes(); + if (StackSizeIsUnlimited() || StackLimit > MaxStackSize) { + VReport(1, "The stack size limit is beyond the maximum supported.\n" + "Re-execing with a stack size below 1TB.\n"); + SetStackSizeLimitInBytes(MaxStackSize); + ReExec(); + } +#endif +} + +static bool liesWithinSingleAppRegion(uptr Start, SIZE_T Size) { + uptr AppStart, AppEnd; + for (int i = 0; getAppRegion(i, &AppStart, &AppEnd); ++i) { + if (Start >= AppStart && Start + Size - 1 <= AppEnd) { + return true; + } + } + return false; +} + +bool fixMmapAddr(void **Addr, SIZE_T Size, int Flags) { + if (*Addr) { + if (!liesWithinSingleAppRegion((uptr)*Addr, Size)) { + VPrintf(1, "mmap conflict: [%p-%p) is not in an app region\n", + *Addr, (uptr)*Addr + Size); + if (Flags & MAP_FIXED) { + errno = EINVAL; + return false; + } else { + *Addr = 0; + } + } + } + return true; +} + +uptr checkMmapResult(uptr Addr, SIZE_T Size) { + if ((void *)Addr == MAP_FAILED) + return Addr; + if (!liesWithinSingleAppRegion(Addr, Size)) { + // FIXME: attempt to dynamically add this as an app region if it + // fits our shadow criteria. + // We could also try to remap somewhere else. + Printf("ERROR: unsupported mapping at [%p-%p)\n", Addr, Addr+Size); + Die(); + } + return Addr; +} + +} // namespace __esan + +#endif // SANITIZER_FREEBSD || SANITIZER_LINUX diff --git a/lib/esan/esan_shadow.h b/lib/esan/esan_shadow.h new file mode 100644 index 0000000000000..f8f154ef7cca5 --- /dev/null +++ b/lib/esan/esan_shadow.h @@ -0,0 +1,203 @@ +//===-- esan_shadow.h -------------------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// Shadow memory mappings for the esan run-time. +//===----------------------------------------------------------------------===// + +#ifndef ESAN_SHADOW_H +#define ESAN_SHADOW_H + +#include <sanitizer_common/sanitizer_platform.h> + +#if SANITIZER_WORDSIZE != 64 +#error Only 64-bit is supported +#endif + +namespace __esan { + +#if SANITIZER_LINUX && defined(__x86_64__) +// Linux x86_64 +// +// Application memory falls into these 5 regions (ignoring the corner case +// of PIE with a non-zero PT_LOAD base): +// +// [0x00000000'00000000, 0x00000100'00000000) non-PIE + heap +// [0x00005500'00000000, 0x00005700'00000000) PIE +// [0x00007e00'00000000, 0x00007fff'ff600000) libraries + stack, part 1 +// [0x00007fff'ff601000, 0x00008000'00000000) libraries + stack, part 2 +// [0xffffffff'ff600000, 0xffffffff'ff601000) vsyscall +// +// Although we can ignore the vsyscall for the most part as there are few data +// references there (other sanitizers ignore it), we enforce a gap inside the +// library region to distinguish the vsyscall's shadow, considering this gap to +// be an invalid app region. +// We disallow application memory outside of those 5 regions. +// Our regions assume that the stack rlimit is less than a terabyte (otherwise +// the Linux kernel's default mmap region drops below 0x7e00'), which we enforce +// at init time (we can support larger and unlimited sizes for shadow +// scaledowns, but it is difficult for 1:1 mappings). +// +// Our shadow memory is scaled from a 1:1 mapping and supports a scale +// specified at library initialization time that can be any power-of-2 +// scaledown (1x, 2x, 4x, 8x, 16x, etc.). +// +// We model our shadow memory after Umbra, a library used by the Dr. Memory +// tool: https://github.com/DynamoRIO/drmemory/blob/master/umbra/umbra_x64.c. +// We use Umbra's scheme as it was designed to support different +// offsets, it supports two different shadow mappings (which we may want to +// use for future tools), and it ensures that the shadow of a shadow will +// not overlap either shadow memory or application memory. +// +// This formula translates from application memory to shadow memory: +// +// shadow(app) = ((app & 0x00000fff'ffffffff) + offset) >> scale +// +// Where the offset for 1:1 is 0x00001300'00000000. For other scales, the +// offset is shifted left by the scale, except for scales of 1 and 2 where +// it must be tweaked in order to pass the double-shadow test +// (see the "shadow(shadow)" comments below): +// scale == 0: 0x00001300'000000000 +// scale == 1: 0x00002200'000000000 +// scale == 2: 0x00004400'000000000 +// scale >= 3: (0x00001300'000000000 << scale) +// +// Do not pass in the open-ended end value to the formula as it will fail. +// +// The resulting shadow memory regions for a 0 scaling are: +// +// [0x00001300'00000000, 0x00001400'00000000) +// [0x00001800'00000000, 0x00001a00'00000000) +// [0x00002100'00000000, 0x000022ff'ff600000) +// [0x000022ff'ff601000, 0x00002300'00000000) +// [0x000022ff'ff600000, 0x000022ff'ff601000] +// +// We also want to ensure that a wild access by the application into the shadow +// regions will not corrupt our own shadow memory. shadow(shadow) ends up +// disjoint from shadow(app): +// +// [0x00001600'00000000, 0x00001700'00000000) +// [0x00001b00'00000000, 0x00001d00'00000000) +// [0x00001400'00000000, 0x000015ff'ff600000] +// [0x000015ff'ff601000, 0x00001600'00000000] +// [0x000015ff'ff600000, 0x000015ff'ff601000] + +struct ApplicationRegion { + uptr Start; + uptr End; + bool ShadowMergedWithPrev; +}; + +static const struct ApplicationRegion AppRegions[] = { + {0x0000000000000000ull, 0x0000010000000000u, false}, + {0x0000550000000000u, 0x0000570000000000u, false}, + // We make one shadow mapping to hold the shadow regions for all 3 of these + // app regions, as the mappings interleave, and the gap between the 3rd and + // 4th scales down below a page. + {0x00007e0000000000u, 0x00007fffff600000u, false}, + {0x00007fffff601000u, 0x0000800000000000u, true}, + {0xffffffffff600000u, 0xffffffffff601000u, true}, +}; +static const u32 NumAppRegions = sizeof(AppRegions)/sizeof(AppRegions[0]); + +// See the comment above: we do not currently support a stack size rlimit +// equal to or larger than 1TB. +static const uptr MaxStackSize = (1ULL << 40) - 4096; + +class ShadowMapping { +public: + static const uptr Mask = 0x00000fffffffffffu; + // The scale and offset vary by tool. + uptr Scale; + uptr Offset; + void initialize(uptr ShadowScale) { + static const uptr OffsetArray[3] = { + 0x0000130000000000u, + 0x0000220000000000u, + 0x0000440000000000u, + }; + Scale = ShadowScale; + if (Scale <= 2) + Offset = OffsetArray[Scale]; + else + Offset = OffsetArray[0] << Scale; + } +}; +extern ShadowMapping Mapping; +#else +// We'll want to use templatized functions over the ShadowMapping once +// we support more platforms. +#error Platform not supported +#endif + +static inline bool getAppRegion(u32 i, uptr *Start, uptr *End) { + if (i >= NumAppRegions) + return false; + *Start = AppRegions[i].Start; + *End = AppRegions[i].End; + return true; +} + +ALWAYS_INLINE +bool isAppMem(uptr Mem) { + for (u32 i = 0; i < NumAppRegions; ++i) { + if (Mem >= AppRegions[i].Start && Mem < AppRegions[i].End) + return true; + } + return false; +} + +ALWAYS_INLINE +uptr appToShadow(uptr App) { + return (((App & ShadowMapping::Mask) + Mapping.Offset) >> Mapping.Scale); +} + +static inline bool getShadowRegion(u32 i, uptr *Start, uptr *End) { + if (i >= NumAppRegions) + return false; + u32 UnmergedShadowCount = 0; + u32 AppIdx; + for (AppIdx = 0; AppIdx < NumAppRegions; ++AppIdx) { + if (!AppRegions[AppIdx].ShadowMergedWithPrev) { + if (UnmergedShadowCount == i) + break; + UnmergedShadowCount++; + } + } + if (AppIdx >= NumAppRegions || UnmergedShadowCount != i) + return false; + *Start = appToShadow(AppRegions[AppIdx].Start); + // The formula fails for the end itself. + *End = appToShadow(AppRegions[AppIdx].End - 1) + 1; + // Merge with adjacent shadow regions: + for (++AppIdx; AppIdx < NumAppRegions; ++AppIdx) { + if (!AppRegions[AppIdx].ShadowMergedWithPrev) + break; + *Start = Min(*Start, appToShadow(AppRegions[AppIdx].Start)); + *End = Max(*End, appToShadow(AppRegions[AppIdx].End - 1) + 1); + } + return true; +} + +ALWAYS_INLINE +bool isShadowMem(uptr Mem) { + // We assume this is not used on any critical performance path and so there's + // no need to hardcode the mapping results. + for (uptr i = 0; i < NumAppRegions; ++i) { + if (Mem >= appToShadow(AppRegions[i].Start) && + Mem < appToShadow(AppRegions[i].End - 1) + 1) + return true; + } + return false; +} + +} // namespace __esan + +#endif /* ESAN_SHADOW_H */ diff --git a/lib/esan/esan_sideline.h b/lib/esan/esan_sideline.h new file mode 100644 index 0000000000000..aa3fae1db3183 --- /dev/null +++ b/lib/esan/esan_sideline.h @@ -0,0 +1,61 @@ +//===-- esan_sideline.h -----------------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// Esan sideline thread support. +//===----------------------------------------------------------------------===// + +#ifndef ESAN_SIDELINE_H +#define ESAN_SIDELINE_H + +#include "sanitizer_common/sanitizer_atomic.h" +#include "sanitizer_common/sanitizer_internal_defs.h" + +namespace __esan { + +typedef void (*SidelineFunc)(void *Arg); + +// Currently only one sideline thread is supported. +// It calls the SidelineFunc passed to launchThread once on each sample at the +// given frequency in real time (i.e., wall clock time). +class SidelineThread { +public: + // We cannot initialize any fields in the constructor as it will be called + // *after* launchThread for a static instance, as esan.module_ctor is called + // before static initializers. + SidelineThread() {} + ~SidelineThread() {} + + // To simplify declaration in sanitizer code where we want to avoid + // heap allocations, the constructor and destructor do nothing and + // launchThread and joinThread do the real work. + // They should each be called just once. + bool launchThread(SidelineFunc takeSample, void *Arg, u32 FreqMilliSec); + bool joinThread(); + + // Must be called from the sideline thread itself. + bool adjustTimer(u32 FreqMilliSec); + +private: + static int runSideline(void *Arg); + static void registerSignal(int SigNum); + static void handleSidelineSignal(int SigNum, void *SigInfo, void *Ctx); + + char *Stack; + SidelineFunc sampleFunc; + void *FuncArg; + u32 Freq; + uptr SidelineId; + atomic_uintptr_t SidelineExit; +}; + +} // namespace __esan + +#endif // ESAN_SIDELINE_H diff --git a/lib/esan/esan_sideline_linux.cpp b/lib/esan/esan_sideline_linux.cpp new file mode 100644 index 0000000000000..d04f5909d6a27 --- /dev/null +++ b/lib/esan/esan_sideline_linux.cpp @@ -0,0 +1,177 @@ +//===-- esan_sideline_linux.cpp ---------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// Support for a separate or "sideline" tool thread on Linux. +//===----------------------------------------------------------------------===// + +#include "sanitizer_common/sanitizer_platform.h" +#if SANITIZER_LINUX + +#include "esan_sideline.h" +#include "sanitizer_common/sanitizer_atomic.h" +#include "sanitizer_common/sanitizer_common.h" +#include "sanitizer_common/sanitizer_linux.h" +#include <errno.h> +#include <sched.h> +#include <sys/prctl.h> +#include <sys/signal.h> +#include <sys/time.h> +#include <sys/types.h> +#include <sys/wait.h> + +namespace __esan { + +static const int SigAltStackSize = 4*1024; +static const int SidelineStackSize = 4*1024; +static const uptr SidelineIdUninitialized = 1; + +// FIXME: we'll need some kind of TLS (can we trust that a pthread key will +// work in our non-POSIX thread?) to access our data in our signal handler +// with multiple sideline threads. For now we assume there is only one +// sideline thread and we use a dirty solution of a global var. +static SidelineThread *TheThread; + +// We aren't passing SA_NODEFER so the same signal is blocked while here. +void SidelineThread::handleSidelineSignal(int SigNum, void *SigInfo, + void *Ctx) { + VPrintf(3, "Sideline signal %d\n", SigNum); + CHECK_EQ(SigNum, SIGALRM); + // See above about needing TLS to avoid this global var. + SidelineThread *Thread = TheThread; + if (atomic_load(&Thread->SidelineExit, memory_order_relaxed) != 0) + return; + Thread->sampleFunc(Thread->FuncArg); +} + +void SidelineThread::registerSignal(int SigNum) { + __sanitizer_sigaction SigAct; + internal_memset(&SigAct, 0, sizeof(SigAct)); + SigAct.sigaction = handleSidelineSignal; + // We do not pass SA_NODEFER as we want to block the same signal. + SigAct.sa_flags = SA_ONSTACK | SA_SIGINFO; + int Res = internal_sigaction(SigNum, &SigAct, nullptr); + CHECK_EQ(Res, 0); +} + +int SidelineThread::runSideline(void *Arg) { + VPrintf(1, "Sideline thread starting\n"); + SidelineThread *Thread = static_cast<SidelineThread*>(Arg); + + // If the parent dies, we want to exit also. + internal_prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); + + // Set up a signal handler on an alternate stack for safety. + InternalScopedBuffer<char> StackMap(SigAltStackSize); + struct sigaltstack SigAltStack; + SigAltStack.ss_sp = StackMap.data(); + SigAltStack.ss_size = SigAltStackSize; + SigAltStack.ss_flags = 0; + internal_sigaltstack(&SigAltStack, nullptr); + + // We inherit the signal mask from the app thread. In case + // we weren't created at init time, we ensure the mask is empty. + __sanitizer_sigset_t SigSet; + internal_sigfillset(&SigSet); + int Res = internal_sigprocmask(SIG_UNBLOCK, &SigSet, nullptr); + CHECK_EQ(Res, 0); + + registerSignal(SIGALRM); + + bool TimerSuccess = Thread->adjustTimer(Thread->Freq); + CHECK(TimerSuccess); + + // We loop, doing nothing but handling itimer signals. + while (atomic_load(&TheThread->SidelineExit, memory_order_relaxed) == 0) + sched_yield(); + + if (!Thread->adjustTimer(0)) + VPrintf(1, "Failed to disable timer\n"); + + VPrintf(1, "Sideline thread exiting\n"); + return 0; +} + +bool SidelineThread::launchThread(SidelineFunc takeSample, void *Arg, + u32 FreqMilliSec) { + // This can only be called once. However, we can't clear a field in + // the constructor and check for that here as the constructor for + // a static instance is called *after* our module_ctor and thus after + // this routine! Thus we rely on the TheThread check below. + CHECK(TheThread == nullptr); // Only one sideline thread is supported. + TheThread = this; + sampleFunc = takeSample; + FuncArg = Arg; + Freq = FreqMilliSec; + atomic_store(&SidelineExit, 0, memory_order_relaxed); + + // We do without a guard page. + Stack = static_cast<char*>(MmapOrDie(SidelineStackSize, "SidelineStack")); + // We need to handle the return value from internal_clone() not having been + // assigned yet (for our CHECK in adjustTimer()) so we ensure this has a + // sentinel value. + SidelineId = SidelineIdUninitialized; + // By omitting CLONE_THREAD, the child is in its own thread group and will not + // receive any of the application's signals. + SidelineId = internal_clone( + runSideline, Stack + SidelineStackSize, + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_UNTRACED, + this, nullptr /* parent_tidptr */, + nullptr /* newtls */, nullptr /* child_tidptr */); + int ErrCode; + if (internal_iserror(SidelineId, &ErrCode)) { + Printf("FATAL: EfficiencySanitizer failed to spawn a thread (code %d).\n", + ErrCode); + Die(); + return false; // Not reached. + } + return true; +} + +bool SidelineThread::joinThread() { + VPrintf(1, "Joining sideline thread\n"); + bool Res = true; + atomic_store(&SidelineExit, 1, memory_order_relaxed); + while (true) { + uptr Status = internal_waitpid(SidelineId, nullptr, __WALL); + int ErrCode; + if (!internal_iserror(Status, &ErrCode)) + break; + if (ErrCode == EINTR) + continue; + VPrintf(1, "Failed to join sideline thread (errno %d)\n", ErrCode); + Res = false; + break; + } + UnmapOrDie(Stack, SidelineStackSize); + return Res; +} + +// Must be called from the sideline thread itself. +bool SidelineThread::adjustTimer(u32 FreqMilliSec) { + // The return value of internal_clone() may not have been assigned yet: + CHECK(internal_getpid() == SidelineId || + SidelineId == SidelineIdUninitialized); + Freq = FreqMilliSec; + struct itimerval TimerVal; + TimerVal.it_interval.tv_sec = (time_t) Freq / 1000; + TimerVal.it_interval.tv_usec = (time_t) (Freq % 1000) * 1000; + TimerVal.it_value.tv_sec = (time_t) Freq / 1000; + TimerVal.it_value.tv_usec = (time_t) (Freq % 1000) * 1000; + // As we're in a different thread group, we cannot use either + // ITIMER_PROF or ITIMER_VIRTUAL without taking up scheduled + // time ourselves: thus we must use real time. + int Res = setitimer(ITIMER_REAL, &TimerVal, nullptr); + return (Res == 0); +} + +} // namespace __esan + +#endif // SANITIZER_LINUX diff --git a/lib/esan/working_set.cpp b/lib/esan/working_set.cpp new file mode 100644 index 0000000000000..f39111993c337 --- /dev/null +++ b/lib/esan/working_set.cpp @@ -0,0 +1,279 @@ +//===-- working_set.cpp ---------------------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// This file contains working-set-specific code. +//===----------------------------------------------------------------------===// + +#include "working_set.h" +#include "esan.h" +#include "esan_circular_buffer.h" +#include "esan_flags.h" +#include "esan_shadow.h" +#include "esan_sideline.h" +#include "sanitizer_common/sanitizer_procmaps.h" + +// We shadow every cache line of app memory with one shadow byte. +// - The highest bit of each shadow byte indicates whether the corresponding +// cache line has ever been accessed. +// - The lowest bit of each shadow byte indicates whether the corresponding +// cache line was accessed since the last sample. +// - The other bits are used for working set snapshots at successively +// lower frequencies, each bit to the left from the lowest bit stepping +// down the frequency by 2 to the power of getFlags()->snapshot_step. +// Thus we have something like this: +// Bit 0: Since last sample +// Bit 1: Since last 2^2 samples +// Bit 2: Since last 2^4 samples +// Bit 3: ... +// Bit 7: Ever accessed. +// We live with races in accessing each shadow byte. +typedef unsigned char byte; + +namespace __esan { + +// Our shadow memory assumes that the line size is 64. +static const u32 CacheLineSize = 64; + +// See the shadow byte layout description above. +static const u32 TotalWorkingSetBitIdx = 7; +// We accumulate to the left until we hit this bit. +// We don't need to accumulate to the final bit as it's set on each ref +// by the compiler instrumentation. +static const u32 MaxAccumBitIdx = 6; +static const u32 CurWorkingSetBitIdx = 0; +static const byte ShadowAccessedVal = + (1 << TotalWorkingSetBitIdx) | (1 << CurWorkingSetBitIdx); + +static SidelineThread Thread; +// If we use real-time-based timer samples this won't overflow in any realistic +// scenario, but if we switch to some other unit (such as memory accesses) we +// may want to consider a 64-bit int. +static u32 SnapshotNum; + +// We store the wset size for each of 8 different sampling frequencies. +static const u32 NumFreq = 8; // One for each bit of our shadow bytes. +// We cannot use static objects as the global destructor is called +// prior to our finalize routine. +// These are each circular buffers, sized up front. +CircularBuffer<u32> SizePerFreq[NumFreq]; +// We cannot rely on static initializers (they may run too late) but +// we record the size here for clarity: +u32 CircularBufferSizes[NumFreq] = { + // These are each mmap-ed so our minimum is one page. + 32*1024, + 16*1024, + 8*1024, + 4*1024, + 4*1024, + 4*1024, + 4*1024, + 4*1024, +}; + +void processRangeAccessWorkingSet(uptr PC, uptr Addr, SIZE_T Size, + bool IsWrite) { + if (Size == 0) + return; + SIZE_T I = 0; + uptr LineSize = getFlags()->cache_line_size; + // As Addr+Size could overflow at the top of a 32-bit address space, + // we avoid the simpler formula that rounds the start and end. + SIZE_T NumLines = Size / LineSize + + // Add any extra at the start or end adding on an extra line: + (LineSize - 1 + Addr % LineSize + Size % LineSize) / LineSize; + byte *Shadow = (byte *)appToShadow(Addr); + // Write shadow bytes until we're word-aligned. + while (I < NumLines && (uptr)Shadow % 4 != 0) { + if ((*Shadow & ShadowAccessedVal) != ShadowAccessedVal) + *Shadow |= ShadowAccessedVal; + ++Shadow; + ++I; + } + // Write whole shadow words at a time. + // Using a word-stride loop improves the runtime of a microbenchmark of + // memset calls by 10%. + u32 WordValue = ShadowAccessedVal | ShadowAccessedVal << 8 | + ShadowAccessedVal << 16 | ShadowAccessedVal << 24; + while (I + 4 <= NumLines) { + if ((*(u32*)Shadow & WordValue) != WordValue) + *(u32*)Shadow |= WordValue; + Shadow += 4; + I += 4; + } + // Write any trailing shadow bytes. + while (I < NumLines) { + if ((*Shadow & ShadowAccessedVal) != ShadowAccessedVal) + *Shadow |= ShadowAccessedVal; + ++Shadow; + ++I; + } +} + +// This routine will word-align ShadowStart and ShadowEnd prior to scanning. +// It does *not* clear for BitIdx==TotalWorkingSetBitIdx, as that top bit +// measures the access during the entire execution and should never be cleared. +static u32 countAndClearShadowValues(u32 BitIdx, uptr ShadowStart, + uptr ShadowEnd) { + u32 WorkingSetSize = 0; + u32 ByteValue = 0x1 << BitIdx; + u32 WordValue = ByteValue | ByteValue << 8 | ByteValue << 16 | + ByteValue << 24; + // Get word aligned start. + ShadowStart = RoundDownTo(ShadowStart, sizeof(u32)); + bool Accum = getFlags()->record_snapshots && BitIdx < MaxAccumBitIdx; + // Do not clear the bit that measures access during the entire execution. + bool Clear = BitIdx < TotalWorkingSetBitIdx; + for (u32 *Ptr = (u32 *)ShadowStart; Ptr < (u32 *)ShadowEnd; ++Ptr) { + if ((*Ptr & WordValue) != 0) { + byte *BytePtr = (byte *)Ptr; + for (u32 j = 0; j < sizeof(u32); ++j) { + if (BytePtr[j] & ByteValue) { + ++WorkingSetSize; + if (Accum) { + // Accumulate to the lower-frequency bit to the left. + BytePtr[j] |= (ByteValue << 1); + } + } + } + if (Clear) { + // Clear this bit from every shadow byte. + *Ptr &= ~WordValue; + } + } + } + return WorkingSetSize; +} + +// Scan shadow memory to calculate the number of cache lines being accessed, +// i.e., the number of non-zero bits indexed by BitIdx in each shadow byte. +// We also clear the lowest bits (most recent working set snapshot). +// We do *not* clear for BitIdx==TotalWorkingSetBitIdx, as that top bit +// measures the access during the entire execution and should never be cleared. +static u32 computeWorkingSizeAndReset(u32 BitIdx) { + u32 WorkingSetSize = 0; + MemoryMappingLayout MemIter(true/*cache*/); + uptr Start, End, Prot; + while (MemIter.Next(&Start, &End, nullptr/*offs*/, nullptr/*file*/, + 0/*file size*/, &Prot)) { + VPrintf(4, "%s: considering %p-%p app=%d shadow=%d prot=%u\n", + __FUNCTION__, Start, End, Prot, isAppMem(Start), + isShadowMem(Start)); + if (isShadowMem(Start) && (Prot & MemoryMappingLayout::kProtectionWrite)) { + VPrintf(3, "%s: walking %p-%p\n", __FUNCTION__, Start, End); + WorkingSetSize += countAndClearShadowValues(BitIdx, Start, End); + } + } + return WorkingSetSize; +} + +// This is invoked from a signal handler but in a sideline thread doing nothing +// else so it is a little less fragile than a typical signal handler. +static void takeSample(void *Arg) { + u32 BitIdx = CurWorkingSetBitIdx; + u32 Freq = 1; + ++SnapshotNum; // Simpler to skip 0 whose mod matches everything. + while (BitIdx <= MaxAccumBitIdx && (SnapshotNum % Freq) == 0) { + u32 NumLines = computeWorkingSizeAndReset(BitIdx); + VReport(1, "%s: snapshot #%5d bit %d freq %4d: %8u\n", SanitizerToolName, + SnapshotNum, BitIdx, Freq, NumLines); + SizePerFreq[BitIdx].push_back(NumLines); + Freq = Freq << getFlags()->snapshot_step; + BitIdx++; + } +} + +unsigned int getSampleCountWorkingSet() +{ + return SnapshotNum; +} + +// Initialization that must be done before any instrumented code is executed. +void initializeShadowWorkingSet() { + CHECK(getFlags()->cache_line_size == CacheLineSize); + registerMemoryFaultHandler(); +} + +void initializeWorkingSet() { + if (getFlags()->record_snapshots) { + for (u32 i = 0; i < NumFreq; ++i) + SizePerFreq[i].initialize(CircularBufferSizes[i]); + Thread.launchThread(takeSample, nullptr, getFlags()->sample_freq); + } +} + +static u32 getPeriodForPrinting(u32 MilliSec, const char *&Unit) { + if (MilliSec > 600000) { + Unit = "min"; + return MilliSec / 60000; + } else if (MilliSec > 10000) { + Unit = "sec"; + return MilliSec / 1000; + } else { + Unit = "ms"; + return MilliSec; + } +} + +static u32 getSizeForPrinting(u32 NumOfCachelines, const char *&Unit) { + // We need a constant to avoid software divide support: + static const u32 KilobyteCachelines = (0x1 << 10) / CacheLineSize; + static const u32 MegabyteCachelines = KilobyteCachelines << 10; + + if (NumOfCachelines > 10 * MegabyteCachelines) { + Unit = "MB"; + return NumOfCachelines / MegabyteCachelines; + } else if (NumOfCachelines > 10 * KilobyteCachelines) { + Unit = "KB"; + return NumOfCachelines / KilobyteCachelines; + } else { + Unit = "Bytes"; + return NumOfCachelines * CacheLineSize; + } +} + +void reportWorkingSet() { + const char *Unit; + if (getFlags()->record_snapshots) { + u32 Freq = 1; + Report(" Total number of samples: %u\n", SnapshotNum); + for (u32 i = 0; i < NumFreq; ++i) { + u32 Time = getPeriodForPrinting(getFlags()->sample_freq*Freq, Unit); + Report(" Samples array #%d at period %u %s\n", i, Time, Unit); + // FIXME: report whether we wrapped around and thus whether we + // have data on the whole run or just the last N samples. + for (u32 j = 0; j < SizePerFreq[i].size(); ++j) { + u32 Size = getSizeForPrinting(SizePerFreq[i][j], Unit); + Report("#%4d: %8u %s (%9u cache lines)\n", j, Size, Unit, + SizePerFreq[i][j]); + } + Freq = Freq << getFlags()->snapshot_step; + } + } + + // Get the working set size for the entire execution. + u32 NumOfCachelines = computeWorkingSizeAndReset(TotalWorkingSetBitIdx); + u32 Size = getSizeForPrinting(NumOfCachelines, Unit); + Report(" %s: the total working set size: %u %s (%u cache lines)\n", + SanitizerToolName, Size, Unit, NumOfCachelines); +} + +int finalizeWorkingSet() { + if (getFlags()->record_snapshots) + Thread.joinThread(); + reportWorkingSet(); + if (getFlags()->record_snapshots) { + for (u32 i = 0; i < NumFreq; ++i) + SizePerFreq[i].free(); + } + return 0; +} + +} // namespace __esan diff --git a/lib/esan/working_set.h b/lib/esan/working_set.h new file mode 100644 index 0000000000000..6a976c3f9b22e --- /dev/null +++ b/lib/esan/working_set.h @@ -0,0 +1,40 @@ +//===-- working_set.h -------------------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// Header for working-set-specific code. +//===----------------------------------------------------------------------===// + +#ifndef WORKING_SET_H +#define WORKING_SET_H + +#include "interception/interception.h" +#include "sanitizer_common/sanitizer_internal_defs.h" + +namespace __esan { + +void initializeWorkingSet(); +void initializeShadowWorkingSet(); +int finalizeWorkingSet(); +void reportWorkingSet(); +unsigned int getSampleCountWorkingSet(); +void processRangeAccessWorkingSet(uptr PC, uptr Addr, SIZE_T Size, + bool IsWrite); + +// Platform-dependent. +void registerMemoryFaultHandler(); +bool processWorkingSetSignal(int SigNum, void (*Handler)(int), + void (**Result)(int)); +bool processWorkingSetSigaction(int SigNum, const void *Act, void *OldAct); +bool processWorkingSetSigprocmask(int How, void *Set, void *OldSet); + +} // namespace __esan + +#endif // WORKING_SET_H diff --git a/lib/esan/working_set_posix.cpp b/lib/esan/working_set_posix.cpp new file mode 100644 index 0000000000000..fcfa87128857f --- /dev/null +++ b/lib/esan/working_set_posix.cpp @@ -0,0 +1,133 @@ +//===-- working_set_posix.cpp -----------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of EfficiencySanitizer, a family of performance tuners. +// +// POSIX-specific working set tool code. +//===----------------------------------------------------------------------===// + +#include "working_set.h" +#include "esan_flags.h" +#include "esan_shadow.h" +#include "sanitizer_common/sanitizer_common.h" +#include "sanitizer_common/sanitizer_linux.h" +#include <signal.h> +#include <sys/mman.h> + +namespace __esan { + +// We only support regular POSIX threads with a single signal handler +// for the whole process == thread group. +// Thus we only need to store one app signal handler. +// FIXME: Store and use any alternate stack and signal flags set by +// the app. For now we just call the app handler from our handler. +static __sanitizer_sigaction AppSigAct; + +bool processWorkingSetSignal(int SigNum, void (*Handler)(int), + void (**Result)(int)) { + VPrintf(2, "%s: %d\n", __FUNCTION__, SigNum); + if (SigNum == SIGSEGV) { + *Result = AppSigAct.handler; + AppSigAct.sigaction = (void (*)(int, void*, void*))Handler; + return false; // Skip real call. + } + return true; +} + +bool processWorkingSetSigaction(int SigNum, const void *ActVoid, + void *OldActVoid) { + VPrintf(2, "%s: %d\n", __FUNCTION__, SigNum); + if (SigNum == SIGSEGV) { + const struct sigaction *Act = (const struct sigaction *) ActVoid; + struct sigaction *OldAct = (struct sigaction *) OldActVoid; + if (OldAct) + internal_memcpy(OldAct, &AppSigAct, sizeof(OldAct)); + if (Act) + internal_memcpy(&AppSigAct, Act, sizeof(AppSigAct)); + return false; // Skip real call. + } + return true; +} + +bool processWorkingSetSigprocmask(int How, void *Set, void *OldSet) { + VPrintf(2, "%s\n", __FUNCTION__); + // All we need to do is ensure that SIGSEGV is not blocked. + // FIXME: we are not fully transparent as we do not pretend that + // SIGSEGV is still blocked on app queries: that would require + // per-thread mask tracking. + if (Set && (How == SIG_BLOCK || How == SIG_SETMASK)) { + if (internal_sigismember((__sanitizer_sigset_t *)Set, SIGSEGV)) { + VPrintf(1, "%s: removing SIGSEGV from the blocked set\n", __FUNCTION__); + internal_sigdelset((__sanitizer_sigset_t *)Set, SIGSEGV); + } + } + return true; +} + +static void reinstateDefaultHandler(int SigNum) { + __sanitizer_sigaction SigAct; + internal_memset(&SigAct, 0, sizeof(SigAct)); + SigAct.sigaction = (void (*)(int, void*, void*)) SIG_DFL; + int Res = internal_sigaction(SigNum, &SigAct, nullptr); + CHECK(Res == 0); + VPrintf(1, "Unregistered for %d handler\n", SigNum); +} + +// If this is a shadow fault, we handle it here; otherwise, we pass it to the +// app to handle it just as the app would do without our tool in place. +static void handleMemoryFault(int SigNum, void *Info, void *Ctx) { + if (SigNum == SIGSEGV) { + // We rely on si_addr being filled in (thus we do not support old kernels). + siginfo_t *SigInfo = (siginfo_t *)Info; + uptr Addr = (uptr)SigInfo->si_addr; + if (isShadowMem(Addr)) { + VPrintf(3, "Shadow fault @%p\n", Addr); + uptr PageSize = GetPageSizeCached(); + int Res = internal_mprotect((void *)RoundDownTo(Addr, PageSize), + PageSize, PROT_READ|PROT_WRITE); + CHECK(Res == 0); + } else if (AppSigAct.sigaction) { + // FIXME: For simplicity we ignore app options including its signal stack + // (we just use ours) and all the delivery flags. + AppSigAct.sigaction(SigNum, Info, Ctx); + } else { + // Crash instead of spinning with infinite faults. + reinstateDefaultHandler(SigNum); + } + } else + UNREACHABLE("signal not registered"); +} + +void registerMemoryFaultHandler() { + // We do not use an alternate signal stack, as doing so would require + // setting it up for each app thread. + // FIXME: This could result in problems with emulating the app's signal + // handling if the app relies on an alternate stack for SIGSEGV. + + // We require that SIGSEGV is not blocked. We use a sigprocmask + // interceptor to ensure that in the future. Here we ensure it for + // the current thread. We assume there are no other threads at this + // point during initialization, or that at least they do not block + // SIGSEGV. + __sanitizer_sigset_t SigSet; + internal_sigemptyset(&SigSet); + internal_sigprocmask(SIG_BLOCK, &SigSet, nullptr); + + __sanitizer_sigaction SigAct; + internal_memset(&SigAct, 0, sizeof(SigAct)); + SigAct.sigaction = handleMemoryFault; + // We want to handle nested signals b/c we need to handle a + // shadow fault in an app signal handler. + SigAct.sa_flags = SA_SIGINFO | SA_NODEFER; + int Res = internal_sigaction(SIGSEGV, &SigAct, &AppSigAct); + CHECK(Res == 0); + VPrintf(1, "Registered for SIGSEGV handler\n"); +} + +} // namespace __esan |