[CodeGen] Use IRBuilder to create llvm.lifetime intrinsics.

[samsonov]

Summary

In addition to easier syntax, IRBuilder makes sure to set correct
debug locations for newly added instructions (bitcast and
llvm.lifetime itself). This restores the original behavior, which
was modified by r234581 (reapplied as r235553).

Extend one of the tests to check for debug locations.

lib/CodeGen/CGDecl.cpp

if (CGM.getCodeGenOpts().OptimizationLevel == 0)
     return nullptr;
 
   // Disable lifetime markers in msan builds.
   // FIXME: Remove this when msan works with lifetime markers.
   if (getLangOpts().Sanitize.has(SanitizerKind::Memory))
     return nullptr;
 
   llvm::Value *SizeV = llvm::ConstantInt::get(Int64Ty, Size);
-  llvm::Value *Args[] = {
-      SizeV,
-      new llvm::BitCastInst(Addr, Int8PtrTy, "", Builder.GetInsertBlock())};
-  llvm::CallInst *C = llvm::CallInst::Create(CGM.getLLVMLifetimeStartFn(), Args,
-                                             "", Builder.GetInsertBlock());
+  Addr = Builder.CreateBitCast(Addr, Int8PtrTy);
+  llvm::Value *Args[] = {SizeV, Addr};
+  llvm::CallInst *C = Builder.CreateCall(CGM.getLLVMLifetimeStartFn(), Args);
   C->setDoesNotThrow();
   return SizeV;
 }
 
 void CodeGenFunction::EmitLifetimeEnd(llvm::Value *Size, llvm::Value *Addr) {
-  llvm::Value *Args[] = {Size, new llvm::BitCastInst(Addr, Int8PtrTy, "",
-                                                     Builder.GetInsertBlock())};
-  llvm::CallInst *C = llvm::CallInst::Create(CGM.getLLVMLifetimeEndFn(), Args,
-                                             "", Builder.GetInsertBlock());
+  Addr = Builder.CreateBitCast(Addr, Int8PtrTy);
+  llvm::Value *Args[] = {Size, Addr};
+  llvm::CallInst *C = Builder.CreateCall(CGM.getLLVMLifetimeEndFn(), Args);
   C->setDoesNotThrow();
 }
 
 /// EmitAutoVarAlloca - Emit the alloca and debug information for a
 /// local variable.  Does not emit initialization or destruction.
 CodeGenFunction::AutoVarEmission
 CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
   QualType Ty = D.getType();

test/CodeGen/cleanup-destslot-simple.c

 // RUN: %clang_cc1 -O1 -triple x86_64-none-linux-gnu -emit-llvm -gline-tables-only %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=LIFETIME
 
 // We shouldn't have markers at -O0 or with msan.
 // RUN: %clang_cc1 -O0 -triple x86_64-none-linux-gnu -emit-llvm -gline-tables-only %s -o - | FileCheck %s --check-prefix=CHECK
 // RUN: %clang_cc1 -O1 -triple x86_64-none-linux-gnu -emit-llvm -gline-tables-only %s -o - -fsanitize=memory | FileCheck %s --check-prefix=CHECK
 
 // There is no exception to handle here, lifetime.end is not a destructor,
 // so there is no need have cleanup dest slot related code
 // CHECK-LABEL: define i32 @test
 int test() {
   int x = 3;
   int *volatile p = &x;
   return *p;
 // CHECK: [[X:%.*]] = alloca i32
 // CHECK: [[P:%.*]] = alloca i32*
-// LIFETIME: call void @llvm.lifetime.start(i64 4, i8* %{{.*}})
-// LIFETIME: call void @llvm.lifetime.start(i64 8, i8* %{{.*}})
+// LIFETIME: call void @llvm.lifetime.start(i64 4, i8* %{{.*}}){{( #[0-9]+)?}}, !dbg
+// LIFETIME: call void @llvm.lifetime.start(i64 8, i8* %{{.*}}){{( #[0-9]+)?}}, !dbg
 // CHECK-NOT: store i32 %{{.*}}, i32* %cleanup.dest.slot
+// LIFETIME: call void @llvm.lifetime.end(i64 8, {{.*}}){{( #[0-9]+)?}}, !dbg
+// LIFETIME: call void @llvm.lifetime.end(i64 4, {{.*}}){{( #[0-9]+)?}}, !dbg
 }