1 files changed, 68 insertions, 21 deletions

diff --git a/lib/CodeGen/CGDeclCXX.cpp b/lib/CodeGen/CGDeclCXX.cpp
index d8768bee2cdf4..0429978317021 100644
--- a/lib/CodeGen/CGDeclCXX.cpp
+++ b/lib/CodeGen/CGDeclCXX.cpp
@@ -18,6 +18,7 @@
 #include "clang/Frontend/CodeGenOptions.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/MDBuilder.h"
 #include "llvm/Support/Path.h"
 
 using namespace clang;
@@ -259,6 +260,43 @@ void CodeGenFunction::EmitCXXGuardedInit(const VarDecl &D,
   CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr, PerformInit);
 }
 
+void CodeGenFunction::EmitCXXGuardedInitBranch(llvm::Value *NeedsInit,
+                                               llvm::BasicBlock *InitBlock,
+                                               llvm::BasicBlock *NoInitBlock,
+                                               GuardKind Kind,
+                                               const VarDecl *D) {
+  assert((Kind == GuardKind::TlsGuard || D) && "no guarded variable");
+
+  // A guess at how many times we will enter the initialization of a
+  // variable, depending on the kind of variable.
+  static const uint64_t InitsPerTLSVar = 1024;
+  static const uint64_t InitsPerLocalVar = 1024 * 1024;
+
+  llvm::MDNode *Weights;
+  if (Kind == GuardKind::VariableGuard && !D->isLocalVarDecl()) {
+    // For non-local variables, don't apply any weighting for now. Due to our
+    // use of COMDATs, we expect there to be at most one initialization of the
+    // variable per DSO, but we have no way to know how many DSOs will try to
+    // initialize the variable.
+    Weights = nullptr;
+  } else {
+    uint64_t NumInits;
+    // FIXME: For the TLS case, collect and use profiling information to
+    // determine a more accurate brach weight.
+    if (Kind == GuardKind::TlsGuard || D->getTLSKind())
+      NumInits = InitsPerTLSVar;
+    else
+      NumInits = InitsPerLocalVar;
+
+    // The probability of us entering the initializer is
+    //   1 / (total number of times we attempt to initialize the variable).
+    llvm::MDBuilder MDHelper(CGM.getLLVMContext());
+    Weights = MDHelper.createBranchWeights(1, NumInits - 1);
+  }
+
+  Builder.CreateCondBr(NeedsInit, InitBlock, NoInitBlock, Weights);
+}
+
 llvm::Function *CodeGenModule::CreateGlobalInitOrDestructFunction(
     llvm::FunctionType *FTy, const Twine &Name, const CGFunctionInfo &FI,
     SourceLocation Loc, bool TLS) {
@@ -278,17 +316,29 @@ llvm::Function *CodeGenModule::CreateGlobalInitOrDestructFunction(
   if (!getLangOpts().Exceptions)
     Fn->setDoesNotThrow();
 
-  if (!isInSanitizerBlacklist(Fn, Loc)) {
-    if (getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address |
-                                        SanitizerKind::KernelAddress))
-      Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
-    if (getLangOpts().Sanitize.has(SanitizerKind::Thread))
-      Fn->addFnAttr(llvm::Attribute::SanitizeThread);
-    if (getLangOpts().Sanitize.has(SanitizerKind::Memory))
-      Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
-    if (getLangOpts().Sanitize.has(SanitizerKind::SafeStack))
-      Fn->addFnAttr(llvm::Attribute::SafeStack);
-  }
+  if (getLangOpts().Sanitize.has(SanitizerKind::Address) &&
+      !isInSanitizerBlacklist(SanitizerKind::Address, Fn, Loc))
+    Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
+
+  if (getLangOpts().Sanitize.has(SanitizerKind::KernelAddress) &&
+      !isInSanitizerBlacklist(SanitizerKind::KernelAddress, Fn, Loc))
+    Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
+
+  if (getLangOpts().Sanitize.has(SanitizerKind::HWAddress) &&
+      !isInSanitizerBlacklist(SanitizerKind::HWAddress, Fn, Loc))
+    Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
+
+  if (getLangOpts().Sanitize.has(SanitizerKind::Thread) &&
+      !isInSanitizerBlacklist(SanitizerKind::Thread, Fn, Loc))
+    Fn->addFnAttr(llvm::Attribute::SanitizeThread);
+
+  if (getLangOpts().Sanitize.has(SanitizerKind::Memory) &&
+      !isInSanitizerBlacklist(SanitizerKind::Memory, Fn, Loc))
+    Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
+
+  if (getLangOpts().Sanitize.has(SanitizerKind::SafeStack) &&
+      !isInSanitizerBlacklist(SanitizerKind::SafeStack, Fn, Loc))
+    Fn->addFnAttr(llvm::Attribute::SafeStack);
 
   return Fn;
 }
@@ -449,16 +499,12 @@ CodeGenModule::EmitCXXGlobalInitFunc() {
     PrioritizedCXXGlobalInits.clear();
   }
 
-  SmallString<128> FileName;
-  SourceManager &SM = Context.getSourceManager();
-  if (const FileEntry *MainFile = SM.getFileEntryForID(SM.getMainFileID())) {
-    // Include the filename in the symbol name. Including "sub_" matches gcc and
-    // makes sure these symbols appear lexicographically behind the symbols with
-    // priority emitted above.
-    FileName = llvm::sys::path::filename(MainFile->getName());
-  } else {
+  // Include the filename in the symbol name. Including "sub_" matches gcc and
+  // makes sure these symbols appear lexicographically behind the symbols with
+  // priority emitted above.
+  SmallString<128> FileName = llvm::sys::path::filename(getModule().getName());
+  if (FileName.empty())
     FileName = "<null>";
-  }
 
   for (size_t i = 0; i < FileName.size(); ++i) {
     // Replace everything that's not [a-zA-Z0-9._] with a _. This set happens
@@ -539,7 +585,8 @@ CodeGenFunction::GenerateCXXGlobalInitFunc(llvm::Function *Fn,
                                                  "guard.uninitialized");
       llvm::BasicBlock *InitBlock = createBasicBlock("init");
       ExitBlock = createBasicBlock("exit");
-      Builder.CreateCondBr(Uninit, InitBlock, ExitBlock);
+      EmitCXXGuardedInitBranch(Uninit, InitBlock, ExitBlock,
+                               GuardKind::TlsGuard, nullptr);
       EmitBlock(InitBlock);
       // Mark as initialized before initializing anything else. If the
       // initializers use previously-initialized thread_local vars, that's