[CodeGen] Fix calling llvm.var.annotation outside of a basic block.

When we have an annotated local variable after a function returns, we
generate IR that fails verification with the error

> Instruction referencing instruction not embedded in a basic block!

And it means that bitcast referencing alloca doesn't have a parent basic
block.

Fix by checking if we are at an unreachable point and skip emitting
annotations. This approach is similar to the way we emit variable
initializer and debug info.

rdar://problem/46200420

Reviewers: rjmccall

Reviewed By: rjmccall

Subscribers: aprantl, jkorous, dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D58147

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@355166 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CGDecl.cpp b/lib/CodeGen/CGDecl.cpp
index 9a790c80dbdc975035b88f65e532571cae5dd5da..91b0c970625f83c7d5407767494582e44bf4fdf7 100644 (file)
--- a/lib/CodeGen/CGDecl.cpp
+++ b/lib/CodeGen/CGDecl.cpp
@@ -1577,7 +1577,7 @@ CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
     (void)DI->EmitDeclareOfAutoVariable(&D, address.getPointer(), Builder);
   }
 
-  if (D.hasAttr<AnnotateAttr>())
+  if (D.hasAttr<AnnotateAttr>() && HaveInsertPoint())
     EmitVarAnnotations(&D, address.getPointer());
 
   // Make sure we call @llvm.lifetime.end.

diff --git a/test/CodeGen/annotations-builtin.c b/test/CodeGen/annotations-builtin.c
index 8a3b3ffcec28684a3341339edda982145e3c0b7a..e6dd3587af71c23d601d2e3065ba73bd805970a8 100644 (file)
--- a/test/CodeGen/annotations-builtin.c
+++ b/test/CodeGen/annotations-builtin.c
@@ -43,4 +43,7 @@ int main(int argc, char **argv) {
 // CHECK: call i32 @llvm.annotation.i32
 // CHECK: inttoptr {{.*}} to i8**
     return 0;
+
+    int after_return = __builtin_annotation(argc, "annotation_a");
+// CHECK-NOT: call i32 @llvm.annotation.i32
 }

diff --git a/test/CodeGen/annotations-var.c b/test/CodeGen/annotations-var.c
index 6e8ad34c65156dd13f5d1fb6ef0a271097a570af..3dc6dca3e7517caeea7f831b43df89dc7334557c 100644 (file)
--- a/test/CodeGen/annotations-var.c
+++ b/test/CodeGen/annotations-var.c
@@ -39,10 +39,19 @@ void local(void) {
 // LOCAL-NEXT: call void @llvm.var.annotation(i8* [[T0]], i8* getelementptr inbounds ([15 x i8], [15 x i8]* @{{.*}}), i8* getelementptr inbounds ({{.*}}), i32 33)
 }
 
+void local_after_return(void) {
+    return;
+    int localvar __attribute__((annotate("localvar_after_return"))) = 3;
+// Test we are not emitting instructions like bitcast or call outside of a basic block.
+// LOCAL-LABEL: define void @local_after_return()
+// LOCAL:      [[LOCALVAR:%.*]] = alloca i32,
+// LOCAL-NEXT: ret void
+}
+
 void undef(void) {
     int undefvar __attribute__((annotate("undefvar_ann_0")));
 // UNDEF-LABEL: define void @undef()
 // UNDEF:      [[UNDEFVAR:%.*]] = alloca i32,
 // UNDEF-NEXT: [[T0:%.*]] = bitcast i32* [[UNDEFVAR]] to i8*
-// UNDEF-NEXT: call void @llvm.var.annotation(i8* [[T0]], i8* getelementptr inbounds ([15 x i8], [15 x i8]* @{{.*}}), i8* getelementptr inbounds ({{.*}}), i32 43)
+// UNDEF-NEXT: call void @llvm.var.annotation(i8* [[T0]], i8* getelementptr inbounds ([15 x i8], [15 x i8]* @{{.*}}), i8* getelementptr inbounds ({{.*}}), i32 52)
 }