1 files changed, 55 insertions, 149 deletions

diff --git a/lib/sanitizer_common/sanitizer_stacktrace.cc b/lib/sanitizer_common/sanitizer_stacktrace.cc
index 724c29c86b667..70ce26bde0d20 100644
--- a/lib/sanitizer_common/sanitizer_stacktrace.cc
+++ b/lib/sanitizer_common/sanitizer_stacktrace.cc
@@ -12,20 +12,13 @@
 //===----------------------------------------------------------------------===//
 
 #include "sanitizer_common.h"
+#include "sanitizer_flags.h"
 #include "sanitizer_procmaps.h"
 #include "sanitizer_stacktrace.h"
 #include "sanitizer_symbolizer.h"
 
 namespace __sanitizer {
-const char *StripPathPrefix(const char *filepath,
-                            const char *strip_file_prefix) {
-  if (filepath == 0) return 0;
-  if (filepath == internal_strstr(filepath, strip_file_prefix))
-    return filepath + internal_strlen(strip_file_prefix);
-  return filepath;
-}
 
-// ----------------------- StackTrace ----------------------------- {{{1
 uptr StackTrace::GetPreviousInstructionPc(uptr pc) {
 #ifdef __arm__
   // Cancel Thumb bit.
@@ -41,32 +34,21 @@ uptr StackTrace::GetPreviousInstructionPc(uptr pc) {
 #endif
 }
 
-static void PrintStackFramePrefix(uptr frame_num, uptr pc) {
-  Printf("    #%zu 0x%zx", frame_num, pc);
-}
-
-static void PrintSourceLocation(const char *file, int line, int column,
-                                const char *strip_file_prefix) {
-  CHECK(file);
-  Printf(" %s", StripPathPrefix(file, strip_file_prefix));
-  if (line > 0) {
-    Printf(":%d", line);
-    if (column > 0)
-      Printf(":%d", column);
-  }
-}
-
-static void PrintModuleAndOffset(const char *module, uptr offset,
-                                 const char *strip_file_prefix) {
-  Printf(" (%s+0x%zx)", StripPathPrefix(module, strip_file_prefix), offset);
+static void PrintStackFramePrefix(InternalScopedString *buffer, uptr frame_num,
+                                  uptr pc) {
+  buffer->append("    #%zu 0x%zx", frame_num, pc);
 }
 
 void StackTrace::PrintStack(const uptr *addr, uptr size,
-                            bool symbolize, const char *strip_file_prefix,
-                            SymbolizeCallback symbolize_callback ) {
+                            SymbolizeCallback symbolize_callback) {
+  if (addr == 0) {
+    Printf("<empty stack>\n\n");
+    return;
+  }
   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
   InternalScopedBuffer<char> buff(GetPageSizeCached() * 2);
   InternalScopedBuffer<AddressInfo> addr_frames(64);
+  InternalScopedString frame_desc(GetPageSizeCached() * 2);
   uptr frame_num = 0;
   for (uptr i = 0; i < size && addr[i]; i++) {
     // PCs in stack traces are actually the return addresses, that is,
@@ -77,50 +59,60 @@ void StackTrace::PrintStack(const uptr *addr, uptr size,
     if (symbolize_callback) {
       if (symbolize_callback((void*)pc, buff.data(), buff.size())) {
         addr_frames_num = 1;
-        PrintStackFramePrefix(frame_num, pc);
+        frame_desc.clear();
+        PrintStackFramePrefix(&frame_desc, frame_num, pc);
         // We can't know anything about the string returned by external
         // symbolizer, but if it starts with filename, try to strip path prefix
         // from it.
-        Printf(" %s\n", StripPathPrefix(buff.data(), strip_file_prefix));
+        frame_desc.append(
+            " %s",
+            StripPathPrefix(buff.data(), common_flags()->strip_path_prefix));
+        Printf("%s\n", frame_desc.data());
         frame_num++;
       }
     }
-    if (symbolize && addr_frames_num == 0 && &SymbolizeCode) {
+    if (common_flags()->symbolize && addr_frames_num == 0) {
       // Use our own (online) symbolizer, if necessary.
-      addr_frames_num = SymbolizeCode(pc, addr_frames.data(),
-                                      addr_frames.size());
+      if (Symbolizer *sym = Symbolizer::GetOrNull())
+        addr_frames_num =
+            sym->SymbolizeCode(pc, addr_frames.data(), addr_frames.size());
       for (uptr j = 0; j < addr_frames_num; j++) {
         AddressInfo &info = addr_frames[j];
-        PrintStackFramePrefix(frame_num, pc);
+        frame_desc.clear();
+        PrintStackFramePrefix(&frame_desc, frame_num, pc);
         if (info.function) {
-          Printf(" in %s", info.function);
+          frame_desc.append(" in %s", info.function);
         }
         if (info.file) {
-          PrintSourceLocation(info.file, info.line, info.column,
-                              strip_file_prefix);
+          frame_desc.append(" ");
+          PrintSourceLocation(&frame_desc, info.file, info.line, info.column);
         } else if (info.module) {
-          PrintModuleAndOffset(info.module, info.module_offset,
-                               strip_file_prefix);
+          frame_desc.append(" ");
+          PrintModuleAndOffset(&frame_desc, info.module, info.module_offset);
         }
-        Printf("\n");
-        info.Clear();
+        Printf("%s\n", frame_desc.data());
         frame_num++;
+        info.Clear();
       }
     }
     if (addr_frames_num == 0) {
       // If online symbolization failed, try to output at least module and
       // offset for instruction.
-      PrintStackFramePrefix(frame_num, pc);
+      frame_desc.clear();
+      PrintStackFramePrefix(&frame_desc, frame_num, pc);
       uptr offset;
       if (proc_maps.GetObjectNameAndOffset(pc, &offset,
                                            buff.data(), buff.size(),
                                            /* protection */0)) {
-        PrintModuleAndOffset(buff.data(), offset, strip_file_prefix);
+        frame_desc.append(" ");
+        PrintModuleAndOffset(&frame_desc, buff.data(), offset);
       }
-      Printf("\n");
+      Printf("%s\n", frame_desc.data());
       frame_num++;
     }
   }
+  // Always print a trailing empty line after stack trace.
+  Printf("\n");
 }
 
 uptr StackTrace::GetCurrentPc() {
@@ -128,17 +120,23 @@ uptr StackTrace::GetCurrentPc() {
 }
 
 void StackTrace::FastUnwindStack(uptr pc, uptr bp,
-                                 uptr stack_top, uptr stack_bottom) {
-  CHECK(size == 0 && trace[0] == pc);
+                                 uptr stack_top, uptr stack_bottom,
+                                 uptr max_depth) {
+  if (max_depth == 0) {
+    size = 0;
+    return;
+  }
+  trace[0] = pc;
   size = 1;
   uhwptr *frame = (uhwptr *)bp;
   uhwptr *prev_frame = frame - 1;
+  if (stack_top < 4096) return;  // Sanity check for stack top.
   // Avoid infinite loop when frame == frame[0] by using frame > prev_frame.
   while (frame > prev_frame &&
          frame < (uhwptr *)stack_top - 2 &&
          frame > (uhwptr *)stack_bottom &&
          IsAligned((uptr)frame, sizeof(*frame)) &&
-         size < max_size) {
+         size < max_depth) {
     uhwptr pc1 = frame[1];
     if (pc1 != pc) {
       trace[size++] = (uptr) pc1;
@@ -156,111 +154,19 @@ void StackTrace::PopStackFrames(uptr count) {
   }
 }
 
-// On 32-bits we don't compress stack traces.
-// On 64-bits we compress stack traces: if a given pc differes slightly from
-// the previous one, we record a 31-bit offset instead of the full pc.
-SANITIZER_INTERFACE_ATTRIBUTE
-uptr StackTrace::CompressStack(StackTrace *stack, u32 *compressed, uptr size) {
-#if SANITIZER_WORDSIZE == 32
-  // Don't compress, just copy.
-  uptr res = 0;
-  for (uptr i = 0; i < stack->size && i < size; i++) {
-    compressed[i] = stack->trace[i];
-    res++;
-  }
-  if (stack->size < size)
-    compressed[stack->size] = 0;
-#else  // 64 bits, compress.
-  uptr prev_pc = 0;
-  const uptr kMaxOffset = (1ULL << 30) - 1;
-  uptr c_index = 0;
-  uptr res = 0;
-  for (uptr i = 0, n = stack->size; i < n; i++) {
-    uptr pc = stack->trace[i];
-    if (!pc) break;
-    if ((s64)pc < 0) break;
-    // Printf("C pc[%zu] %zx\n", i, pc);
-    if (prev_pc - pc < kMaxOffset || pc - prev_pc < kMaxOffset) {
-      uptr offset = (s64)(pc - prev_pc);
-      offset |= (1U << 31);
-      if (c_index >= size) break;
-      // Printf("C co[%zu] offset %zx\n", i, offset);
-      compressed[c_index++] = offset;
-    } else {
-      uptr hi = pc >> 32;
-      uptr lo = (pc << 32) >> 32;
-      CHECK_EQ((hi & (1 << 31)), 0);
-      if (c_index + 1 >= size) break;
-      // Printf("C co[%zu] hi/lo: %zx %zx\n", c_index, hi, lo);
-      compressed[c_index++] = hi;
-      compressed[c_index++] = lo;
-    }
-    res++;
-    prev_pc = pc;
-  }
-  if (c_index < size)
-    compressed[c_index] = 0;
-  if (c_index + 1 < size)
-    compressed[c_index + 1] = 0;
-#endif  // SANITIZER_WORDSIZE
-
-  // debug-only code
-#if 0
-  StackTrace check_stack;
-  UncompressStack(&check_stack, compressed, size);
-  if (res < check_stack.size) {
-    Printf("res %zu check_stack.size %zu; c_size %zu\n", res,
-           check_stack.size, size);
-  }
-  // |res| may be greater than check_stack.size, because
-  // UncompressStack(CompressStack(stack)) eliminates the 0x0 frames.
-  CHECK(res >= check_stack.size);
-  CHECK_EQ(0, REAL(memcmp)(check_stack.trace, stack->trace,
-                          check_stack.size * sizeof(uptr)));
-#endif
-
-  return res;
+static bool MatchPc(uptr cur_pc, uptr trace_pc, uptr threshold) {
+  return cur_pc - trace_pc <= threshold || trace_pc - cur_pc <= threshold;
 }
 
-SANITIZER_INTERFACE_ATTRIBUTE
-void StackTrace::UncompressStack(StackTrace *stack,
-                                 u32 *compressed, uptr size) {
-#if SANITIZER_WORDSIZE == 32
-  // Don't uncompress, just copy.
-  stack->size = 0;
-  for (uptr i = 0; i < size && i < kStackTraceMax; i++) {
-    if (!compressed[i]) break;
-    stack->size++;
-    stack->trace[i] = compressed[i];
-  }
-#else  // 64 bits, uncompress
-  uptr prev_pc = 0;
-  stack->size = 0;
-  for (uptr i = 0; i < size && stack->size < kStackTraceMax; i++) {
-    u32 x = compressed[i];
-    uptr pc = 0;
-    if (x & (1U << 31)) {
-      // Printf("U co[%zu] offset: %x\n", i, x);
-      // this is an offset
-      s32 offset = x;
-      offset = (offset << 1) >> 1;  // remove the 31-byte and sign-extend.
-      pc = prev_pc + offset;
-      CHECK(pc);
-    } else {
-      // CHECK(i + 1 < size);
-      if (i + 1 >= size) break;
-      uptr hi = x;
-      uptr lo = compressed[i+1];
-      // Printf("U co[%zu] hi/lo: %zx %zx\n", i, hi, lo);
-      i++;
-      pc = (hi << 32) | lo;
-      if (!pc) break;
-    }
-    // Printf("U pc[%zu] %zx\n", stack->size, pc);
-    stack->trace[stack->size++] = pc;
-    prev_pc = pc;
+uptr StackTrace::LocatePcInTrace(uptr pc) {
+  // Use threshold to find PC in stack trace, as PC we want to unwind from may
+  // slightly differ from return address in the actual unwinded stack trace.
+  const int kPcThreshold = 96;
+  for (uptr i = 0; i < size; ++i) {
+    if (MatchPc(pc, trace[i], kPcThreshold))
+      return i;
   }
-#endif  // SANITIZER_WORDSIZE
+  return 0;
 }
 
 }  // namespace __sanitizer