Introduce sanstats tool and llvm::CreateSanitizerStatReport function.

This is part of a new statistics gathering feature for the sanitizers.
See clang/docs/SanitizerStats.rst for further info and docs.

Differential Revision: http://reviews.llvm.org/D16174

llvm-svn: 257970

1 files changed, 108 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Utils/SanitizerStats.cpp b/llvm/lib/Transforms/Utils/SanitizerStats.cpp
new file mode 100644
index 00000000000..af3df2fd948
--- /dev/null
+++ b/llvm/lib/Transforms/Utils/SanitizerStats.cpp
@@ -0,0 +1,108 @@
+//===- SanitizerStats.cpp - Sanitizer statistics gathering ----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Implements code generation for sanitizer statistics gathering.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Utils/SanitizerStats.h"
+#include "llvm/Transforms/Utils/ModuleUtils.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Module.h"
+
+using namespace llvm;
+
+SanitizerStatReport::SanitizerStatReport(Module *M) : M(M) {
+  StatTy = ArrayType::get(Type::getInt8PtrTy(M->getContext()), 2);
+  EmptyModuleStatsTy = makeModuleStatsTy();
+
+  ModuleStatsGV = new GlobalVariable(*M, EmptyModuleStatsTy, false,
+                                     GlobalValue::InternalLinkage, 0);
+}
+
+ArrayType *SanitizerStatReport::makeModuleStatsArrayTy() {
+  return ArrayType::get(StatTy, Inits.size());
+}
+
+StructType *SanitizerStatReport::makeModuleStatsTy() {
+  return StructType::get(M->getContext(), {Type::getInt8PtrTy(M->getContext()),
+                                           Type::getInt32Ty(M->getContext()),
+                                           makeModuleStatsArrayTy()});
+}
+
+void SanitizerStatReport::create(IRBuilder<> &B, SanitizerStatKind SK) {
+  Function *F = B.GetInsertBlock()->getParent();
+  Module *M = F->getParent();
+  PointerType *Int8PtrTy = B.getInt8PtrTy();
+  IntegerType *IntPtrTy = B.getIntPtrTy(M->getDataLayout());
+  ArrayType *StatTy = ArrayType::get(Int8PtrTy, 2);
+
+  Inits.push_back(ConstantArray::get(
+      StatTy,
+      {Constant::getNullValue(Int8PtrTy),
+       ConstantExpr::getIntToPtr(
+           ConstantInt::get(IntPtrTy, uint64_t(SK) << (IntPtrTy->getBitWidth() -
+                                                       kSanitizerStatKindBits)),
+           Int8PtrTy)}));
+
+  FunctionType *StatReportTy =
+      FunctionType::get(B.getVoidTy(), Int8PtrTy, false);
+  Constant *StatReport = M->getOrInsertFunction(
+      "__sanitizer_stat_report", StatReportTy);
+
+  auto InitAddr = ConstantExpr::getGetElementPtr(
+      EmptyModuleStatsTy, ModuleStatsGV,
+      ArrayRef<Constant *>{
+          ConstantInt::get(IntPtrTy, 0), ConstantInt::get(B.getInt32Ty(), 2),
+          ConstantInt::get(IntPtrTy, Inits.size() - 1),
+      });
+  B.CreateCall(StatReport, ConstantExpr::getBitCast(InitAddr, Int8PtrTy));
+}
+
+void SanitizerStatReport::finish() {
+  if (Inits.empty()) {
+    ModuleStatsGV->eraseFromParent();
+    return;
+  }
+
+  PointerType *Int8PtrTy = Type::getInt8PtrTy(M->getContext());
+  IntegerType *Int32Ty = Type::getInt32Ty(M->getContext());
+  Type *VoidTy = Type::getVoidTy(M->getContext());
+
+  // Create a new ModuleStatsGV to replace the old one. We can't just set the
+  // old one's initializer because its type is different.
+  auto NewModuleStatsGV = new GlobalVariable(
+      *M, makeModuleStatsTy(), false, GlobalValue::InternalLinkage,
+      ConstantStruct::getAnon(
+          {Constant::getNullValue(Int8PtrTy),
+           ConstantInt::get(Int32Ty, Inits.size()),
+           ConstantArray::get(makeModuleStatsArrayTy(), Inits)}));
+  ModuleStatsGV->replaceAllUsesWith(
+      ConstantExpr::getBitCast(NewModuleStatsGV, ModuleStatsGV->getType()));
+  ModuleStatsGV->eraseFromParent();
+
+  // Create a global constructor to register NewModuleStatsGV.
+  auto F = Function::Create(FunctionType::get(VoidTy, false),
+                            GlobalValue::InternalLinkage, "", M);
+  auto BB = BasicBlock::Create(M->getContext(), "", F);
+  IRBuilder<> B(BB);
+
+  FunctionType *StatInitTy = FunctionType::get(VoidTy, Int8PtrTy, false);
+  Constant *StatInit = M->getOrInsertFunction(
+      "__sanitizer_stat_init", StatInitTy);
+
+  B.CreateCall(StatInit, ConstantExpr::getBitCast(NewModuleStatsGV, Int8PtrTy));
+  B.CreateRetVoid();
+
+  appendToGlobalCtors(*M, F, 0);
+}