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-rw-r--r--llvm/lib/Transforms/Utils/SymbolRewriter.cpp584
1 files changed, 584 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Utils/SymbolRewriter.cpp b/llvm/lib/Transforms/Utils/SymbolRewriter.cpp
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index 000000000000..5d380dcf231c
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+++ b/llvm/lib/Transforms/Utils/SymbolRewriter.cpp
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+//===- SymbolRewriter.cpp - Symbol Rewriter -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// SymbolRewriter is a LLVM pass which can rewrite symbols transparently within
+// existing code. It is implemented as a compiler pass and is configured via a
+// YAML configuration file.
+//
+// The YAML configuration file format is as follows:
+//
+// RewriteMapFile := RewriteDescriptors
+// RewriteDescriptors := RewriteDescriptor | RewriteDescriptors
+// RewriteDescriptor := RewriteDescriptorType ':' '{' RewriteDescriptorFields '}'
+// RewriteDescriptorFields := RewriteDescriptorField | RewriteDescriptorFields
+// RewriteDescriptorField := FieldIdentifier ':' FieldValue ','
+// RewriteDescriptorType := Identifier
+// FieldIdentifier := Identifier
+// FieldValue := Identifier
+// Identifier := [0-9a-zA-Z]+
+//
+// Currently, the following descriptor types are supported:
+//
+// - function: (function rewriting)
+// + Source (original name of the function)
+// + Target (explicit transformation)
+// + Transform (pattern transformation)
+// + Naked (boolean, whether the function is undecorated)
+// - global variable: (external linkage global variable rewriting)
+// + Source (original name of externally visible variable)
+// + Target (explicit transformation)
+// + Transform (pattern transformation)
+// - global alias: (global alias rewriting)
+// + Source (original name of the aliased name)
+// + Target (explicit transformation)
+// + Transform (pattern transformation)
+//
+// Note that source and exactly one of [Target, Transform] must be provided
+//
+// New rewrite descriptors can be created. Addding a new rewrite descriptor
+// involves:
+//
+// a) extended the rewrite descriptor kind enumeration
+// (<anonymous>::RewriteDescriptor::RewriteDescriptorType)
+// b) implementing the new descriptor
+// (c.f. <anonymous>::ExplicitRewriteFunctionDescriptor)
+// c) extending the rewrite map parser
+// (<anonymous>::RewriteMapParser::parseEntry)
+//
+// Specify to rewrite the symbols using the `-rewrite-symbols` option, and
+// specify the map file to use for the rewriting via the `-rewrite-map-file`
+// option.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Utils/SymbolRewriter.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/ilist.h"
+#include "llvm/ADT/iterator_range.h"
+#include "llvm/IR/Comdat.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/GlobalAlias.h"
+#include "llvm/IR/GlobalObject.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Value.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/ErrorOr.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Regex.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/YAMLParser.h"
+#include <memory>
+#include <string>
+#include <vector>
+
+using namespace llvm;
+using namespace SymbolRewriter;
+
+#define DEBUG_TYPE "symbol-rewriter"
+
+static cl::list<std::string> RewriteMapFiles("rewrite-map-file",
+ cl::desc("Symbol Rewrite Map"),
+ cl::value_desc("filename"),
+ cl::Hidden);
+
+static void rewriteComdat(Module &M, GlobalObject *GO,
+ const std::string &Source,
+ const std::string &Target) {
+ if (Comdat *CD = GO->getComdat()) {
+ auto &Comdats = M.getComdatSymbolTable();
+
+ Comdat *C = M.getOrInsertComdat(Target);
+ C->setSelectionKind(CD->getSelectionKind());
+ GO->setComdat(C);
+
+ Comdats.erase(Comdats.find(Source));
+ }
+}
+
+namespace {
+
+template <RewriteDescriptor::Type DT, typename ValueType,
+ ValueType *(Module::*Get)(StringRef) const>
+class ExplicitRewriteDescriptor : public RewriteDescriptor {
+public:
+ const std::string Source;
+ const std::string Target;
+
+ ExplicitRewriteDescriptor(StringRef S, StringRef T, const bool Naked)
+ : RewriteDescriptor(DT), Source(Naked ? StringRef("\01" + S.str()) : S),
+ Target(T) {}
+
+ bool performOnModule(Module &M) override;
+
+ static bool classof(const RewriteDescriptor *RD) {
+ return RD->getType() == DT;
+ }
+};
+
+} // end anonymous namespace
+
+template <RewriteDescriptor::Type DT, typename ValueType,
+ ValueType *(Module::*Get)(StringRef) const>
+bool ExplicitRewriteDescriptor<DT, ValueType, Get>::performOnModule(Module &M) {
+ bool Changed = false;
+ if (ValueType *S = (M.*Get)(Source)) {
+ if (GlobalObject *GO = dyn_cast<GlobalObject>(S))
+ rewriteComdat(M, GO, Source, Target);
+
+ if (Value *T = (M.*Get)(Target))
+ S->setValueName(T->getValueName());
+ else
+ S->setName(Target);
+
+ Changed = true;
+ }
+ return Changed;
+}
+
+namespace {
+
+template <RewriteDescriptor::Type DT, typename ValueType,
+ ValueType *(Module::*Get)(StringRef) const,
+ iterator_range<typename iplist<ValueType>::iterator>
+ (Module::*Iterator)()>
+class PatternRewriteDescriptor : public RewriteDescriptor {
+public:
+ const std::string Pattern;
+ const std::string Transform;
+
+ PatternRewriteDescriptor(StringRef P, StringRef T)
+ : RewriteDescriptor(DT), Pattern(P), Transform(T) { }
+
+ bool performOnModule(Module &M) override;
+
+ static bool classof(const RewriteDescriptor *RD) {
+ return RD->getType() == DT;
+ }
+};
+
+} // end anonymous namespace
+
+template <RewriteDescriptor::Type DT, typename ValueType,
+ ValueType *(Module::*Get)(StringRef) const,
+ iterator_range<typename iplist<ValueType>::iterator>
+ (Module::*Iterator)()>
+bool PatternRewriteDescriptor<DT, ValueType, Get, Iterator>::
+performOnModule(Module &M) {
+ bool Changed = false;
+ for (auto &C : (M.*Iterator)()) {
+ std::string Error;
+
+ std::string Name = Regex(Pattern).sub(Transform, C.getName(), &Error);
+ if (!Error.empty())
+ report_fatal_error("unable to transforn " + C.getName() + " in " +
+ M.getModuleIdentifier() + ": " + Error);
+
+ if (C.getName() == Name)
+ continue;
+
+ if (GlobalObject *GO = dyn_cast<GlobalObject>(&C))
+ rewriteComdat(M, GO, C.getName(), Name);
+
+ if (Value *V = (M.*Get)(Name))
+ C.setValueName(V->getValueName());
+ else
+ C.setName(Name);
+
+ Changed = true;
+ }
+ return Changed;
+}
+
+namespace {
+
+/// Represents a rewrite for an explicitly named (function) symbol. Both the
+/// source function name and target function name of the transformation are
+/// explicitly spelt out.
+using ExplicitRewriteFunctionDescriptor =
+ ExplicitRewriteDescriptor<RewriteDescriptor::Type::Function, Function,
+ &Module::getFunction>;
+
+/// Represents a rewrite for an explicitly named (global variable) symbol. Both
+/// the source variable name and target variable name are spelt out. This
+/// applies only to module level variables.
+using ExplicitRewriteGlobalVariableDescriptor =
+ ExplicitRewriteDescriptor<RewriteDescriptor::Type::GlobalVariable,
+ GlobalVariable, &Module::getGlobalVariable>;
+
+/// Represents a rewrite for an explicitly named global alias. Both the source
+/// and target name are explicitly spelt out.
+using ExplicitRewriteNamedAliasDescriptor =
+ ExplicitRewriteDescriptor<RewriteDescriptor::Type::NamedAlias, GlobalAlias,
+ &Module::getNamedAlias>;
+
+/// Represents a rewrite for a regular expression based pattern for functions.
+/// A pattern for the function name is provided and a transformation for that
+/// pattern to determine the target function name create the rewrite rule.
+using PatternRewriteFunctionDescriptor =
+ PatternRewriteDescriptor<RewriteDescriptor::Type::Function, Function,
+ &Module::getFunction, &Module::functions>;
+
+/// Represents a rewrite for a global variable based upon a matching pattern.
+/// Each global variable matching the provided pattern will be transformed as
+/// described in the transformation pattern for the target. Applies only to
+/// module level variables.
+using PatternRewriteGlobalVariableDescriptor =
+ PatternRewriteDescriptor<RewriteDescriptor::Type::GlobalVariable,
+ GlobalVariable, &Module::getGlobalVariable,
+ &Module::globals>;
+
+/// PatternRewriteNamedAliasDescriptor - represents a rewrite for global
+/// aliases which match a given pattern. The provided transformation will be
+/// applied to each of the matching names.
+using PatternRewriteNamedAliasDescriptor =
+ PatternRewriteDescriptor<RewriteDescriptor::Type::NamedAlias, GlobalAlias,
+ &Module::getNamedAlias, &Module::aliases>;
+
+} // end anonymous namespace
+
+bool RewriteMapParser::parse(const std::string &MapFile,
+ RewriteDescriptorList *DL) {
+ ErrorOr<std::unique_ptr<MemoryBuffer>> Mapping =
+ MemoryBuffer::getFile(MapFile);
+
+ if (!Mapping)
+ report_fatal_error("unable to read rewrite map '" + MapFile + "': " +
+ Mapping.getError().message());
+
+ if (!parse(*Mapping, DL))
+ report_fatal_error("unable to parse rewrite map '" + MapFile + "'");
+
+ return true;
+}
+
+bool RewriteMapParser::parse(std::unique_ptr<MemoryBuffer> &MapFile,
+ RewriteDescriptorList *DL) {
+ SourceMgr SM;
+ yaml::Stream YS(MapFile->getBuffer(), SM);
+
+ for (auto &Document : YS) {
+ yaml::MappingNode *DescriptorList;
+
+ // ignore empty documents
+ if (isa<yaml::NullNode>(Document.getRoot()))
+ continue;
+
+ DescriptorList = dyn_cast<yaml::MappingNode>(Document.getRoot());
+ if (!DescriptorList) {
+ YS.printError(Document.getRoot(), "DescriptorList node must be a map");
+ return false;
+ }
+
+ for (auto &Descriptor : *DescriptorList)
+ if (!parseEntry(YS, Descriptor, DL))
+ return false;
+ }
+
+ return true;
+}
+
+bool RewriteMapParser::parseEntry(yaml::Stream &YS, yaml::KeyValueNode &Entry,
+ RewriteDescriptorList *DL) {
+ yaml::ScalarNode *Key;
+ yaml::MappingNode *Value;
+ SmallString<32> KeyStorage;
+ StringRef RewriteType;
+
+ Key = dyn_cast<yaml::ScalarNode>(Entry.getKey());
+ if (!Key) {
+ YS.printError(Entry.getKey(), "rewrite type must be a scalar");
+ return false;
+ }
+
+ Value = dyn_cast<yaml::MappingNode>(Entry.getValue());
+ if (!Value) {
+ YS.printError(Entry.getValue(), "rewrite descriptor must be a map");
+ return false;
+ }
+
+ RewriteType = Key->getValue(KeyStorage);
+ if (RewriteType.equals("function"))
+ return parseRewriteFunctionDescriptor(YS, Key, Value, DL);
+ else if (RewriteType.equals("global variable"))
+ return parseRewriteGlobalVariableDescriptor(YS, Key, Value, DL);
+ else if (RewriteType.equals("global alias"))
+ return parseRewriteGlobalAliasDescriptor(YS, Key, Value, DL);
+
+ YS.printError(Entry.getKey(), "unknown rewrite type");
+ return false;
+}
+
+bool RewriteMapParser::
+parseRewriteFunctionDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
+ yaml::MappingNode *Descriptor,
+ RewriteDescriptorList *DL) {
+ bool Naked = false;
+ std::string Source;
+ std::string Target;
+ std::string Transform;
+
+ for (auto &Field : *Descriptor) {
+ yaml::ScalarNode *Key;
+ yaml::ScalarNode *Value;
+ SmallString<32> KeyStorage;
+ SmallString<32> ValueStorage;
+ StringRef KeyValue;
+
+ Key = dyn_cast<yaml::ScalarNode>(Field.getKey());
+ if (!Key) {
+ YS.printError(Field.getKey(), "descriptor key must be a scalar");
+ return false;
+ }
+
+ Value = dyn_cast<yaml::ScalarNode>(Field.getValue());
+ if (!Value) {
+ YS.printError(Field.getValue(), "descriptor value must be a scalar");
+ return false;
+ }
+
+ KeyValue = Key->getValue(KeyStorage);
+ if (KeyValue.equals("source")) {
+ std::string Error;
+
+ Source = Value->getValue(ValueStorage);
+ if (!Regex(Source).isValid(Error)) {
+ YS.printError(Field.getKey(), "invalid regex: " + Error);
+ return false;
+ }
+ } else if (KeyValue.equals("target")) {
+ Target = Value->getValue(ValueStorage);
+ } else if (KeyValue.equals("transform")) {
+ Transform = Value->getValue(ValueStorage);
+ } else if (KeyValue.equals("naked")) {
+ std::string Undecorated;
+
+ Undecorated = Value->getValue(ValueStorage);
+ Naked = StringRef(Undecorated).lower() == "true" || Undecorated == "1";
+ } else {
+ YS.printError(Field.getKey(), "unknown key for function");
+ return false;
+ }
+ }
+
+ if (Transform.empty() == Target.empty()) {
+ YS.printError(Descriptor,
+ "exactly one of transform or target must be specified");
+ return false;
+ }
+
+ // TODO see if there is a more elegant solution to selecting the rewrite
+ // descriptor type
+ if (!Target.empty())
+ DL->push_back(std::make_unique<ExplicitRewriteFunctionDescriptor>(
+ Source, Target, Naked));
+ else
+ DL->push_back(
+ std::make_unique<PatternRewriteFunctionDescriptor>(Source, Transform));
+
+ return true;
+}
+
+bool RewriteMapParser::
+parseRewriteGlobalVariableDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
+ yaml::MappingNode *Descriptor,
+ RewriteDescriptorList *DL) {
+ std::string Source;
+ std::string Target;
+ std::string Transform;
+
+ for (auto &Field : *Descriptor) {
+ yaml::ScalarNode *Key;
+ yaml::ScalarNode *Value;
+ SmallString<32> KeyStorage;
+ SmallString<32> ValueStorage;
+ StringRef KeyValue;
+
+ Key = dyn_cast<yaml::ScalarNode>(Field.getKey());
+ if (!Key) {
+ YS.printError(Field.getKey(), "descriptor Key must be a scalar");
+ return false;
+ }
+
+ Value = dyn_cast<yaml::ScalarNode>(Field.getValue());
+ if (!Value) {
+ YS.printError(Field.getValue(), "descriptor value must be a scalar");
+ return false;
+ }
+
+ KeyValue = Key->getValue(KeyStorage);
+ if (KeyValue.equals("source")) {
+ std::string Error;
+
+ Source = Value->getValue(ValueStorage);
+ if (!Regex(Source).isValid(Error)) {
+ YS.printError(Field.getKey(), "invalid regex: " + Error);
+ return false;
+ }
+ } else if (KeyValue.equals("target")) {
+ Target = Value->getValue(ValueStorage);
+ } else if (KeyValue.equals("transform")) {
+ Transform = Value->getValue(ValueStorage);
+ } else {
+ YS.printError(Field.getKey(), "unknown Key for Global Variable");
+ return false;
+ }
+ }
+
+ if (Transform.empty() == Target.empty()) {
+ YS.printError(Descriptor,
+ "exactly one of transform or target must be specified");
+ return false;
+ }
+
+ if (!Target.empty())
+ DL->push_back(std::make_unique<ExplicitRewriteGlobalVariableDescriptor>(
+ Source, Target,
+ /*Naked*/ false));
+ else
+ DL->push_back(std::make_unique<PatternRewriteGlobalVariableDescriptor>(
+ Source, Transform));
+
+ return true;
+}
+
+bool RewriteMapParser::
+parseRewriteGlobalAliasDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
+ yaml::MappingNode *Descriptor,
+ RewriteDescriptorList *DL) {
+ std::string Source;
+ std::string Target;
+ std::string Transform;
+
+ for (auto &Field : *Descriptor) {
+ yaml::ScalarNode *Key;
+ yaml::ScalarNode *Value;
+ SmallString<32> KeyStorage;
+ SmallString<32> ValueStorage;
+ StringRef KeyValue;
+
+ Key = dyn_cast<yaml::ScalarNode>(Field.getKey());
+ if (!Key) {
+ YS.printError(Field.getKey(), "descriptor key must be a scalar");
+ return false;
+ }
+
+ Value = dyn_cast<yaml::ScalarNode>(Field.getValue());
+ if (!Value) {
+ YS.printError(Field.getValue(), "descriptor value must be a scalar");
+ return false;
+ }
+
+ KeyValue = Key->getValue(KeyStorage);
+ if (KeyValue.equals("source")) {
+ std::string Error;
+
+ Source = Value->getValue(ValueStorage);
+ if (!Regex(Source).isValid(Error)) {
+ YS.printError(Field.getKey(), "invalid regex: " + Error);
+ return false;
+ }
+ } else if (KeyValue.equals("target")) {
+ Target = Value->getValue(ValueStorage);
+ } else if (KeyValue.equals("transform")) {
+ Transform = Value->getValue(ValueStorage);
+ } else {
+ YS.printError(Field.getKey(), "unknown key for Global Alias");
+ return false;
+ }
+ }
+
+ if (Transform.empty() == Target.empty()) {
+ YS.printError(Descriptor,
+ "exactly one of transform or target must be specified");
+ return false;
+ }
+
+ if (!Target.empty())
+ DL->push_back(std::make_unique<ExplicitRewriteNamedAliasDescriptor>(
+ Source, Target,
+ /*Naked*/ false));
+ else
+ DL->push_back(std::make_unique<PatternRewriteNamedAliasDescriptor>(
+ Source, Transform));
+
+ return true;
+}
+
+namespace {
+
+class RewriteSymbolsLegacyPass : public ModulePass {
+public:
+ static char ID; // Pass identification, replacement for typeid
+
+ RewriteSymbolsLegacyPass();
+ RewriteSymbolsLegacyPass(SymbolRewriter::RewriteDescriptorList &DL);
+
+ bool runOnModule(Module &M) override;
+
+private:
+ RewriteSymbolPass Impl;
+};
+
+} // end anonymous namespace
+
+char RewriteSymbolsLegacyPass::ID = 0;
+
+RewriteSymbolsLegacyPass::RewriteSymbolsLegacyPass() : ModulePass(ID) {
+ initializeRewriteSymbolsLegacyPassPass(*PassRegistry::getPassRegistry());
+}
+
+RewriteSymbolsLegacyPass::RewriteSymbolsLegacyPass(
+ SymbolRewriter::RewriteDescriptorList &DL)
+ : ModulePass(ID), Impl(DL) {}
+
+bool RewriteSymbolsLegacyPass::runOnModule(Module &M) {
+ return Impl.runImpl(M);
+}
+
+PreservedAnalyses RewriteSymbolPass::run(Module &M, ModuleAnalysisManager &AM) {
+ if (!runImpl(M))
+ return PreservedAnalyses::all();
+
+ return PreservedAnalyses::none();
+}
+
+bool RewriteSymbolPass::runImpl(Module &M) {
+ bool Changed;
+
+ Changed = false;
+ for (auto &Descriptor : Descriptors)
+ Changed |= Descriptor->performOnModule(M);
+
+ return Changed;
+}
+
+void RewriteSymbolPass::loadAndParseMapFiles() {
+ const std::vector<std::string> MapFiles(RewriteMapFiles);
+ SymbolRewriter::RewriteMapParser Parser;
+
+ for (const auto &MapFile : MapFiles)
+ Parser.parse(MapFile, &Descriptors);
+}
+
+INITIALIZE_PASS(RewriteSymbolsLegacyPass, "rewrite-symbols", "Rewrite Symbols",
+ false, false)
+
+ModulePass *llvm::createRewriteSymbolsPass() {
+ return new RewriteSymbolsLegacyPass();
+}
+
+ModulePass *
+llvm::createRewriteSymbolsPass(SymbolRewriter::RewriteDescriptorList &DL) {
+ return new RewriteSymbolsLegacyPass(DL);
+}
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