[CodeGen] Move shouldEmitLifetimeMarkers into more convenient place

[vitalybuka]

Summary

D24693 will need access to it from other places

[vitalybuka]

Removed unrelated test

[vitalybuka]

Fixed accidentally changed test

[vitalybuka]

rebase

[vitalybuka]

rebase

lib/CodeGen/CGDecl.cpp

 /// variable declaration with auto, register, or no storage class specifier.
 /// These turn into simple stack objects, or GlobalValues depending on target.
 void CodeGenFunction::EmitAutoVarDecl(const VarDecl &D) {
   AutoVarEmission emission = EmitAutoVarAlloca(D);
   EmitAutoVarInit(emission);
   EmitAutoVarCleanups(emission);
 }
 
-/// shouldEmitLifetimeMarkers - Decide whether we need emit the life-time
-/// markers.
-static bool shouldEmitLifetimeMarkers(const CodeGenOptions &CGOpts,
-                                      const LangOptions &LangOpts) {
-  // Asan uses markers for use-after-scope checks.
-  if (CGOpts.SanitizeAddressUseAfterScope)
-    return true;
-
-  // Disable lifetime markers in msan builds.
-  // FIXME: Remove this when msan works with lifetime markers.
-  if (LangOpts.Sanitize.has(SanitizerKind::Memory))
-    return false;
-
-  // For now, only in optimized builds.
-  return CGOpts.OptimizationLevel != 0;
-}
-
 /// Emit a lifetime.begin marker if some criteria are satisfied.
 /// \return a pointer to the temporary size Value if a marker was emitted, null
 /// otherwise
 llvm::Value *CodeGenFunction::EmitLifetimeStart(uint64_t Size,
                                                 llvm::Value *Addr) {
-  if (!shouldEmitLifetimeMarkers(CGM.getCodeGenOpts(), getLangOpts()))
+  if (!ShouldEmitLifetimeMarkers)
     return nullptr;
 
   llvm::Value *SizeV = llvm::ConstantInt::get(Int64Ty, Size);
   Addr = Builder.CreateBitCast(Addr, Int8PtrTy);
   llvm::CallInst *C =
       Builder.CreateCall(CGM.getLLVMLifetimeStartFn(), {SizeV, Addr});
   C->setDoesNotThrow();
   return SizeV;

lib/CodeGen/CodeGenFunction.h

private:
   /// BlockByrefInfos - For each __block variable, contains
   /// information about the layout of the variable.
   llvm::DenseMap<const ValueDecl *, BlockByrefInfo> BlockByrefInfos;
 
   llvm::BasicBlock *TerminateLandingPad;
   llvm::BasicBlock *TerminateHandler;
   llvm::BasicBlock *TrapBB;
 
+  /// True if we need emit the life-time markers.
+  const bool ShouldEmitLifetimeMarkers;
+
   /// Add a kernel metadata node to the named metadata node 'opencl.kernels'.
   /// In the kernel metadata node, reference the kernel function and metadata 
   /// nodes for its optional attribute qualifiers (OpenCL 1.1 6.7.2):
   /// - A node for the vec_type_hint(<type>) qualifier contains string
   ///   "vec_type_hint", an undefined value of the <type> data type,
   ///   and a Boolean that is true if the <type> is integer and signed.
   /// - A node for the work_group_size_hint(X,Y,Z) qualifier contains string 
   ///   "work_group_size_hint", and three 32-bit integers X, Y and Z.

lib/CodeGen/CodeGenFunction.cpp

 #include "clang/Sema/SemaDiagnostic.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/MDBuilder.h"
 #include "llvm/IR/Operator.h"
 using namespace clang;
 using namespace CodeGen;
 
+/// shouldEmitLifetimeMarkers - Decide whether we need emit the life-time
+/// markers.
+static bool shouldEmitLifetimeMarkers(const CodeGenOptions &CGOpts,
+                                      const LangOptions &LangOpts) {
+  // Asan uses markers for use-after-scope checks.
+  if (CGOpts.SanitizeAddressUseAfterScope)
+    return true;
+
+  // Disable lifetime markers in msan builds.
+  // FIXME: Remove this when msan works with lifetime markers.
+  if (LangOpts.Sanitize.has(SanitizerKind::Memory))
+    return false;
+
+  // For now, only in optimized builds.
+  return CGOpts.OptimizationLevel != 0;
+}
+
 CodeGenFunction::CodeGenFunction(CodeGenModule &cgm, bool suppressNewContext)
     : CodeGenTypeCache(cgm), CGM(cgm), Target(cgm.getTarget()),
       Builder(cgm, cgm.getModule().getContext(), llvm::ConstantFolder(),
               CGBuilderInserterTy(this)),
       CurFn(nullptr), ReturnValue(Address::invalid()),
-      CapturedStmtInfo(nullptr),
-      SanOpts(CGM.getLangOpts().Sanitize), IsSanitizerScope(false),
-      CurFuncIsThunk(false), AutoreleaseResult(false), SawAsmBlock(false),
-      IsOutlinedSEHHelper(false),
-      BlockInfo(nullptr), BlockPointer(nullptr),
-      LambdaThisCaptureField(nullptr), NormalCleanupDest(nullptr),
-      NextCleanupDestIndex(1), FirstBlockInfo(nullptr), EHResumeBlock(nullptr),
-      ExceptionSlot(nullptr), EHSelectorSlot(nullptr),
-      DebugInfo(CGM.getModuleDebugInfo()),
+      CapturedStmtInfo(nullptr), SanOpts(CGM.getLangOpts().Sanitize),
+      IsSanitizerScope(false), CurFuncIsThunk(false), AutoreleaseResult(false),
+      SawAsmBlock(false), IsOutlinedSEHHelper(false), BlockInfo(nullptr),
+      BlockPointer(nullptr), LambdaThisCaptureField(nullptr),
+      NormalCleanupDest(nullptr), NextCleanupDestIndex(1),
+      FirstBlockInfo(nullptr), EHResumeBlock(nullptr), ExceptionSlot(nullptr),
+      EHSelectorSlot(nullptr), DebugInfo(CGM.getModuleDebugInfo()),
       DisableDebugInfo(false), DidCallStackSave(false), IndirectBranch(nullptr),
       PGO(cgm), SwitchInsn(nullptr), SwitchWeights(nullptr),
       CaseRangeBlock(nullptr), UnreachableBlock(nullptr), NumReturnExprs(0),
       NumSimpleReturnExprs(0), CXXABIThisDecl(nullptr),
       CXXABIThisValue(nullptr), CXXThisValue(nullptr),
       CXXStructorImplicitParamDecl(nullptr),
       CXXStructorImplicitParamValue(nullptr), OutermostConditional(nullptr),
       CurLexicalScope(nullptr), TerminateLandingPad(nullptr),
-      TerminateHandler(nullptr), TrapBB(nullptr) {
+      TerminateHandler(nullptr), TrapBB(nullptr),
+      ShouldEmitLifetimeMarkers(
+          shouldEmitLifetimeMarkers(CGM.getCodeGenOpts(), CGM.getLangOpts())) {
   if (!suppressNewContext)
     CGM.getCXXABI().getMangleContext().startNewFunction();
 
   llvm::FastMathFlags FMF;
   if (CGM.getLangOpts().FastMath)
     FMF.setUnsafeAlgebra();
   if (CGM.getLangOpts().FiniteMathOnly) {
     FMF.setNoNaNs();

test/CodeGen/lifetime2.c

-// RUN: %clang -S -emit-llvm -o - -O2 %s | FileCheck %s -check-prefix=O2
-// RUN: %clang -S -emit-llvm -o - -O0 %s | FileCheck %s -check-prefix=O0
-
-extern int bar(char *A, int n);
-
-// O0-NOT: @llvm.lifetime.start
-int foo (int n) {
-  if (n) {
-// O2: @llvm.lifetime.start
-    char A[100];
-    return bar(A, 1);
-  } else {
-// O2: @llvm.lifetime.start
-    char A[100];
-    return bar(A, 2);
-  }
-}