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Debug Info: Fine-tune the simple return expression location handling to 

only affect functions without a separate return block. This fixes the
linetable for void functions with cleanups and multiple returns.

llvm-svn: 187090
This commit is contained in:
Adrian Prantl 2013-07-25 00:23:42 +00:00
parent 12bdde57a9
commit 524ba1f11d
2 changed files with 48 additions and 8 deletions
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22
clang/lib/CodeGen/CodeGenFunction.cpp
View File

@ -191,14 +191,20 @@ void CodeGenFunction::FinishFunction(SourceLocation EndLoc) {
"mismatched push/pop in break/continue stack!");
bool OnlySimpleReturnStmts = NumSimpleReturnExprs > 0
&& NumSimpleReturnExprs == NumReturnExprs;
// If the function contains only a simple return statement, the
// location before the cleanup code becomes the last useful
// breakpoint in the function, because the simple return expression
// will be evaluated after the cleanup code. To be safe, set the
// debug location for cleanup code to the location of the return
// statement. Otherwise the cleanup code should be at the end of the
// function's lexical scope.
&& NumSimpleReturnExprs == NumReturnExprs
&& ReturnBlock.getBlock()->use_empty();
// Usually the return expression is evaluated before the cleanup
// code. If the function contains only a simple return statement,
// such as a constant, the location before the cleanup code becomes
// the last useful breakpoint in the function, because the simple
// return expression will be evaluated after the cleanup code. To be
// safe, set the debug location for cleanup code to the location of
// the return statement. Otherwise the cleanup code should be at the
// end of the function's lexical scope.
//
// If there are multiple branches to the return block, the branch
// instructions will get the location of the return statements and
// all will be fine.
if (CGDebugInfo *DI = getDebugInfo()) {
if (OnlySimpleReturnStmts)
DI->EmitLocation(Builder, LastStopPoint);

34
clang/test/CodeGenCXX/linetable-cleanup.cpp
View File

@ -7,6 +7,12 @@
// CHECK: call void @_ZN1CD1Ev(%class.C* {{.*}}), !dbg ![[CLEANUP:[0-9]+]]
// CHECK: ret i32 0, !dbg ![[RET:[0-9]+]]
// CHECK: define {{.*}}bar
// CHECK: ret void, !dbg ![[RETBAR:[0-9]+]]
// CHECK: define {{.*}}baz
// CHECK: ret void, !dbg ![[RETBAZ:[0-9]+]]
class C {
public:
~C() {}
@ -22,3 +28,31 @@ int foo()
return 0;
// CHECK: ![[RET]] = metadata !{i32 [[@LINE+1]], i32 0, metadata !{{.*}}, null}
}
void bar()
{
if (!foo())
// CHECK: {{.*}} = metadata !{i32 [[@LINE+1]], i32 0, metadata !{{.*}}, null}
return;
if (foo()) {
C c;
c.i = foo();
}
// Clang creates only a single ret instruction. Make sure it is at a useful line.
// CHECK: ![[RETBAR]] = metadata !{i32 [[@LINE+1]], i32 0, metadata !{{.*}}, null}
}
void baz()
{
if (!foo())
// CHECK: {{.*}} = metadata !{i32 [[@LINE+1]], i32 0, metadata !{{.*}}, null}
return;
if (foo()) {
// no cleanup
// CHECK: {{.*}} = metadata !{i32 [[@LINE+1]], i32 0, metadata !{{.*}}, null}
return;
}
// CHECK: ![[RETBAZ]] = metadata !{i32 [[@LINE+1]], i32 0, metadata !{{.*}}, null}
}