[CodeGen] Don't reemit expressions for pass_object_size params.
This fixes an assertion failure in cases where we had expression
statements that declared variables nested inside of pass_object_size
args. Since we were emitting the same ExprStmt twice (once for the arg,
once for the @llvm.objectsize call), we were getting issues with
redefining locals.
This also means that we can be more lax about when we emit
@llvm.objectsize for pass_object_size args: since we're reusing the
arg's value itself, we don't have to care so much about side-effects.
llvm-svn: 295935
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 446f2a0..19b9c9b 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -420,10 +420,11 @@
llvm::Value *
CodeGenFunction::evaluateOrEmitBuiltinObjectSize(const Expr *E, unsigned Type,
- llvm::IntegerType *ResType) {
+ llvm::IntegerType *ResType,
+ llvm::Value *EmittedE) {
uint64_t ObjectSize;
if (!E->tryEvaluateObjectSize(ObjectSize, getContext(), Type))
- return emitBuiltinObjectSize(E, Type, ResType);
+ return emitBuiltinObjectSize(E, Type, ResType, EmittedE);
return ConstantInt::get(ResType, ObjectSize, /*isSigned=*/true);
}
@@ -432,9 +433,14 @@
/// - A llvm::Argument (if E is a param with the pass_object_size attribute on
/// it)
/// - A call to the @llvm.objectsize intrinsic
+///
+/// EmittedE is the result of emitting `E` as a scalar expr. If it's non-null
+/// and we wouldn't otherwise try to reference a pass_object_size parameter,
+/// we'll call @llvm.objectsize on EmittedE, rather than emitting E.
llvm::Value *
CodeGenFunction::emitBuiltinObjectSize(const Expr *E, unsigned Type,
- llvm::IntegerType *ResType) {
+ llvm::IntegerType *ResType,
+ llvm::Value *EmittedE) {
// We need to reference an argument if the pointer is a parameter with the
// pass_object_size attribute.
if (auto *D = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) {
@@ -457,10 +463,10 @@
// LLVM can't handle Type=3 appropriately, and __builtin_object_size shouldn't
// evaluate E for side-effects. In either case, we shouldn't lower to
// @llvm.objectsize.
- if (Type == 3 || E->HasSideEffects(getContext()))
+ if (Type == 3 || (!EmittedE && E->HasSideEffects(getContext())))
return getDefaultBuiltinObjectSizeResult(Type, ResType);
- Value *Ptr = EmitScalarExpr(E);
+ Value *Ptr = EmittedE ? EmittedE : EmitScalarExpr(E);
assert(Ptr->getType()->isPointerTy() &&
"Non-pointer passed to __builtin_object_size?");
@@ -965,7 +971,8 @@
// We pass this builtin onto the optimizer so that it can figure out the
// object size in more complex cases.
- return RValue::get(emitBuiltinObjectSize(E->getArg(0), Type, ResType));
+ return RValue::get(emitBuiltinObjectSize(E->getArg(0), Type, ResType,
+ /*EmittedE=*/nullptr));
}
case Builtin::BI__builtin_prefetch: {
Value *Locality, *RW, *Address = EmitScalarExpr(E->getArg(0));