[Sanitizer] Introduce SanitizerMetadata class.

It is responsible for generating metadata consumed by sanitizer instrumentation
passes in the backend. Move several methods from CodeGenModule to SanitizerMetadata.
For now the class is stateless, but soon it won't be the case.

Instead of creating globals providing source-level information to ASan, we will create
metadata nodes/strings which will be turned into actual global variables in the
backend (if needed).

No functionality change.

llvm-svn: 214564

7 files changed, 150 insertions, 81 deletions

diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index b42a44342c4..7caa4b241e3 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -345,7 +345,7 @@ void CodeGenFunction::EmitStaticVarDecl(const VarDecl &D,
   DMEntry = castedAddr;
   CGM.setStaticLocalDeclAddress(&D, castedAddr);
 
-  CGM.reportGlobalToASan(var, D);
+  CGM.getSanitizerMetadata()->reportGlobalToASan(var, D);
 
   // Emit global variable debug descriptor for static vars.
   CGDebugInfo *DI = getDebugInfo();
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 512b323ba10..c83cc0ad970 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -2127,7 +2127,7 @@ llvm::Constant *CodeGenFunction::EmitCheckTypeDescriptor(QualType T) {
       CGM.getModule(), Descriptor->getType(),
       /*isConstant=*/true, llvm::GlobalVariable::PrivateLinkage, Descriptor);
   GV->setUnnamedAddr(true);
-  CGM.disableSanitizerForGlobal(GV);
+  CGM.getSanitizerMetadata()->disableSanitizerForGlobal(GV);
 
   // Remember the descriptor for this type.
   CGM.setTypeDescriptorInMap(T, GV);
@@ -2177,7 +2177,7 @@ llvm::Constant *CodeGenFunction::EmitCheckSourceLocation(SourceLocation Loc) {
   PresumedLoc PLoc = getContext().getSourceManager().getPresumedLoc(Loc);
   if (PLoc.isValid()) {
     auto FilenameGV = CGM.GetAddrOfConstantCString(PLoc.getFilename(), ".src");
-    CGM.disableSanitizerForGlobal(FilenameGV);
+    CGM.getSanitizerMetadata()->disableSanitizerForGlobal(FilenameGV);
     Filename = FilenameGV;
     Line = PLoc.getLine();
     Column = PLoc.getColumn();
@@ -2224,7 +2224,7 @@ void CodeGenFunction::EmitCheck(llvm::Value *Checked, StringRef CheckName,
       new llvm::GlobalVariable(CGM.getModule(), Info->getType(), false,
                                llvm::GlobalVariable::PrivateLinkage, Info);
   InfoPtr->setUnnamedAddr(true);
-  CGM.disableSanitizerForGlobal(InfoPtr);
+  CGM.getSanitizerMetadata()->disableSanitizerForGlobal(InfoPtr);
 
   SmallVector<llvm::Value *, 4> Args;
   SmallVector<llvm::Type *, 4> ArgTypes;
diff --git a/clang/lib/CodeGen/CMakeLists.txt b/clang/lib/CodeGen/CMakeLists.txt
index 00a87d87a29..1adba48aada 100644
--- a/clang/lib/CodeGen/CMakeLists.txt
+++ b/clang/lib/CodeGen/CMakeLists.txt
@@ -61,6 +61,7 @@ add_clang_library(clangCodeGen
   MicrosoftCXXABI.cpp
   ModuleBuilder.cpp
   SanitizerBlacklist.cpp
+  SanitizerMetadata.cpp
   TargetInfo.cpp
 
   DEPENDS
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 55d47060ff9..33325b24e5a 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -88,7 +88,8 @@ CodeGenModule::CodeGenModule(ASTContext &C, const CodeGenOptions &CGO,
       BlockObjectDispose(nullptr), BlockDescriptorType(nullptr),
       GenericBlockLiteralType(nullptr), LifetimeStartFn(nullptr),
       LifetimeEndFn(nullptr), SanitizerBL(llvm::SpecialCaseList::createOrDie(
-                                  CGO.SanitizerBlacklistFile)) {
+                                  CGO.SanitizerBlacklistFile)),
+      SanitizerMD(new SanitizerMetadata(*this)) {
 
   // Initialize the type cache.
   llvm::LLVMContext &LLVMContext = M.getContext();
@@ -1933,7 +1934,7 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
   if (NeedsGlobalCtor || NeedsGlobalDtor)
     EmitCXXGlobalVarDeclInitFunc(D, GV, NeedsGlobalCtor);
 
-  reportGlobalToASan(GV, *D, NeedsGlobalCtor);
+  SanitizerMD->reportGlobalToASan(GV, *D, NeedsGlobalCtor);
 
   // Emit global variable debug information.
   if (CGDebugInfo *DI = getModuleDebugInfo())
@@ -1941,72 +1942,6 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
       DI->EmitGlobalVariable(GV, D);
 }
 
-void CodeGenModule::reportGlobalToASan(llvm::GlobalVariable *GV,
-                                       SourceLocation Loc, StringRef Name,
-                                       bool IsDynInit, bool IsBlacklisted) {
-  if (!LangOpts.Sanitize.Address)
-    return;
-  IsDynInit &= !SanitizerBL.isIn(*GV, "init");
-  IsBlacklisted |= SanitizerBL.isIn(*GV);
-
-  llvm::GlobalVariable *LocDescr = nullptr;
-  llvm::GlobalVariable *GlobalName = nullptr;
-  if (!IsBlacklisted) {
-    // Don't generate source location and global name if it is blacklisted -
-    // it won't be instrumented anyway.
-    PresumedLoc PLoc = Context.getSourceManager().getPresumedLoc(Loc);
-    if (PLoc.isValid()) {
-      llvm::Constant *LocData[] = {
-          GetAddrOfConstantCString(PLoc.getFilename()),
-          llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
-                                 PLoc.getLine()),
-          llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
-                                 PLoc.getColumn()),
-      };
-      auto LocStruct = llvm::ConstantStruct::getAnon(LocData);
-      LocDescr = new llvm::GlobalVariable(TheModule, LocStruct->getType(), true,
-                                          llvm::GlobalValue::PrivateLinkage,
-                                          LocStruct, ".asan_loc_descr");
-      LocDescr->setUnnamedAddr(true);
-      // Add LocDescr to llvm.compiler.used, so that it won't be removed by
-      // the optimizer before the ASan instrumentation pass.
-      addCompilerUsedGlobal(LocDescr);
-    }
-    if (!Name.empty()) {
-      GlobalName = GetAddrOfConstantCString(Name);
-      // GlobalName shouldn't be removed by the optimizer.
-      addCompilerUsedGlobal(GlobalName);
-    }
-  }
-
-  llvm::Value *GlobalMetadata[] = {
-      GV, LocDescr, GlobalName,
-      llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsDynInit),
-      llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsBlacklisted)};
-
-  llvm::MDNode *ThisGlobal = llvm::MDNode::get(VMContext, GlobalMetadata);
-  llvm::NamedMDNode *AsanGlobals =
-      TheModule.getOrInsertNamedMetadata("llvm.asan.globals");
-  AsanGlobals->addOperand(ThisGlobal);
-}
-
-void CodeGenModule::reportGlobalToASan(llvm::GlobalVariable *GV,
-                                       const VarDecl &D, bool IsDynInit) {
-  if (!LangOpts.Sanitize.Address)
-    return;
-  std::string QualName;
-  llvm::raw_string_ostream OS(QualName);
-  D.printQualifiedName(OS);
-  reportGlobalToASan(GV, D.getLocation(), OS.str(), IsDynInit);
-}
-
-void CodeGenModule::disableSanitizerForGlobal(llvm::GlobalVariable *GV) {
-  // For now, just make sure the global is not modified by the ASan
-  // instrumentation.
-  if (LangOpts.Sanitize.Address)
-    reportGlobalToASan(GV, SourceLocation(), "", false, true);
-}
-
 static bool isVarDeclStrongDefinition(const VarDecl *D, bool NoCommon) {
   // Don't give variables common linkage if -fno-common was specified unless it
   // was overridden by a NoCommon attribute.
@@ -2800,7 +2735,7 @@ CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) {
   if (Entry)
     *Entry = GV;
 
-  reportGlobalToASan(GV, S->getStrTokenLoc(0), "<string literal>");
+  SanitizerMD->reportGlobalToASan(GV, S->getStrTokenLoc(0), "<string literal>");
   return GV;
 }
 
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index 9533a8dabb2..326e4c7a290 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -17,6 +17,7 @@
 #include "CGVTables.h"
 #include "CodeGenTypes.h"
 #include "SanitizerBlacklist.h"
+#include "SanitizerMetadata.h"
 #include "clang/AST/Attr.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
@@ -473,6 +474,8 @@ class CodeGenModule : public CodeGenTypeCache {
 
   SanitizerBlacklist SanitizerBL;
 
+  std::unique_ptr<SanitizerMetadata> SanitizerMD;
+
   /// @}
 public:
   CodeGenModule(ASTContext &C, const CodeGenOptions &CodeGenOpts,
@@ -1013,14 +1016,9 @@ public:
     return SanitizerBL;
   }
 
-  void reportGlobalToASan(llvm::GlobalVariable *GV, const VarDecl &D,
-                          bool IsDynInit = false);
-  void reportGlobalToASan(llvm::GlobalVariable *GV, SourceLocation Loc,
-                          StringRef Name, bool IsDynInit = false,
-                          bool IsBlacklisted = false);
-
-  /// Disable sanitizer instrumentation for this global.
-  void disableSanitizerForGlobal(llvm::GlobalVariable *GV);
+  SanitizerMetadata *getSanitizerMetadata() {
+    return SanitizerMD.get();
+  }
 
   void addDeferredVTable(const CXXRecordDecl *RD) {
     DeferredVTables.push_back(RD);
diff --git a/clang/lib/CodeGen/SanitizerMetadata.cpp b/clang/lib/CodeGen/SanitizerMetadata.cpp
new file mode 100644
index 00000000000..46191523c8b
--- /dev/null
+++ b/clang/lib/CodeGen/SanitizerMetadata.cpp
@@ -0,0 +1,88 @@
+//===--- SanitizerMetadata.cpp - Blacklist for sanitizers -----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Class which emits metadata consumed by sanitizer instrumentation passes.
+//
+//===----------------------------------------------------------------------===//
+#include "SanitizerMetadata.h"
+#include "CodeGenModule.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/IR/Constants.h"
+
+using namespace clang;
+using namespace CodeGen;
+
+SanitizerMetadata::SanitizerMetadata(CodeGenModule &CGM) : CGM(CGM) {}
+
+void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV,
+                                           SourceLocation Loc, StringRef Name,
+                                           bool IsDynInit, bool IsBlacklisted) {
+  if (!CGM.getLangOpts().Sanitize.Address)
+    return;
+  IsDynInit &= !CGM.getSanitizerBlacklist().isIn(*GV, "init");
+  IsBlacklisted |= CGM.getSanitizerBlacklist().isIn(*GV);
+
+  llvm::GlobalVariable *LocDescr = nullptr;
+  llvm::GlobalVariable *GlobalName = nullptr;
+  llvm::LLVMContext &VMContext = CGM.getLLVMContext();
+  if (!IsBlacklisted) {
+    // Don't generate source location and global name if it is blacklisted -
+    // it won't be instrumented anyway.
+    PresumedLoc PLoc = CGM.getContext().getSourceManager().getPresumedLoc(Loc);
+    if (PLoc.isValid()) {
+      llvm::Constant *LocData[] = {
+          CGM.GetAddrOfConstantCString(PLoc.getFilename()),
+          llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
+                                 PLoc.getLine()),
+          llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
+                                 PLoc.getColumn()),
+      };
+      auto LocStruct = llvm::ConstantStruct::getAnon(LocData);
+      LocDescr = new llvm::GlobalVariable(
+          CGM.getModule(), LocStruct->getType(), true,
+          llvm::GlobalValue::PrivateLinkage, LocStruct, ".asan_loc_descr");
+      LocDescr->setUnnamedAddr(true);
+      // Add LocDescr to llvm.compiler.used, so that it won't be removed by
+      // the optimizer before the ASan instrumentation pass.
+      CGM.addCompilerUsedGlobal(LocDescr);
+    }
+    if (!Name.empty()) {
+      GlobalName = CGM.GetAddrOfConstantCString(Name);
+      // GlobalName shouldn't be removed by the optimizer.
+      CGM.addCompilerUsedGlobal(GlobalName);
+    }
+  }
+
+  llvm::Value *GlobalMetadata[] = {
+      GV, LocDescr, GlobalName,
+      llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsDynInit),
+      llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsBlacklisted)};
+
+  llvm::MDNode *ThisGlobal = llvm::MDNode::get(VMContext, GlobalMetadata);
+  llvm::NamedMDNode *AsanGlobals =
+      CGM.getModule().getOrInsertNamedMetadata("llvm.asan.globals");
+  AsanGlobals->addOperand(ThisGlobal);
+}
+
+void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV,
+                                           const VarDecl &D, bool IsDynInit) {
+  if (!CGM.getLangOpts().Sanitize.Address)
+    return;
+  std::string QualName;
+  llvm::raw_string_ostream OS(QualName);
+  D.printQualifiedName(OS);
+  reportGlobalToASan(GV, D.getLocation(), OS.str(), IsDynInit);
+}
+
+void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) {
+  // For now, just make sure the global is not modified by the ASan
+  // instrumentation.
+  if (CGM.getLangOpts().Sanitize.Address)
+    reportGlobalToASan(GV, SourceLocation(), "", false, true);
+}
diff --git a/clang/lib/CodeGen/SanitizerMetadata.h b/clang/lib/CodeGen/SanitizerMetadata.h
new file mode 100644
index 00000000000..3062b4a62ed
--- /dev/null
+++ b/clang/lib/CodeGen/SanitizerMetadata.h
@@ -0,0 +1,47 @@
+//===--- SanitizerMetadata.h - Metadata for sanitizers ----------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Class which emits metadata consumed by sanitizer instrumentation passes.
+//
+//===----------------------------------------------------------------------===//
+#ifndef CLANG_CODEGEN_SANITIZERMETADATA_H
+#define CLANG_CODEGEN_SANITIZERMETADATA_H
+
+#include "clang/Basic/LLVM.h"
+#include "clang/Basic/SourceLocation.h"
+
+namespace llvm {
+class GlobalVariable;
+}
+
+namespace clang {
+class VarDecl;
+
+namespace CodeGen {
+
+class CodeGenModule;
+
+class SanitizerMetadata {
+  SanitizerMetadata(const SanitizerMetadata &) LLVM_DELETED_FUNCTION;
+  void operator=(const SanitizerMetadata &) LLVM_DELETED_FUNCTION;
+
+  CodeGenModule &CGM;
+public:
+  SanitizerMetadata(CodeGenModule &CGM);
+  void reportGlobalToASan(llvm::GlobalVariable *GV, const VarDecl &D,
+                          bool IsDynInit = false);
+  void reportGlobalToASan(llvm::GlobalVariable *GV, SourceLocation Loc,
+                          StringRef Name, bool IsDynInit = false,
+                          bool IsBlacklisted = false);
+  void disableSanitizerForGlobal(llvm::GlobalVariable *GV);
+};
+}  // end namespace CodeGen
+}  // end namespace clang
+
+#endif