This is an archive of the discontinued LLVM Phabricator instance.

llvm/lib/Transforms/Utils/Evaluator.cpp
190	You have a dyn_cast here that is immediately dereferenced rather than checked. Might be better to just cast (since we know it's a StructType) or dyn_cast outside of the if?

Address comment.

echristo accepted this revision.Dec 4 2020, 10:34 AM

This revision was landed with ongoing or failed builds.Dec 4 2020, 11:06 AM

Closed by commit rGf9c3954a6ec5: Fix for Bug 48055. (authored by hjyamauchi). · Explain Why

This revision was automatically updated to reflect the committed changes.

hjyamauchi added a commit: rGf9c3954a6ec5: Fix for Bug 48055..

Harbormaster completed remote builds in B81121: Diff 309576.Dec 4 2020, 11:28 AM

Revision Contents

Path

Size

llvm/

lib/

Transforms/

Utils/

Evaluator.cpp

4 lines

test/

Transforms/

GlobalOpt/

evaluate-bitcast-4.ll

29 lines

Diff 309576

llvm/lib/Transforms/Utils/Evaluator.cpp

	Show First 20 Lines • Show All 177 Lines • ▼ Show 20 Lines
	/// pointers to try. Returns the first non-null return value from Func, or			/// pointers to try. Returns the first non-null return value from Func, or
	/// nullptr if the type can't be introspected further.			/// nullptr if the type can't be introspected further.
	static Constant *			static Constant *
	evaluateBitcastFromPtr(Constant *Ptr, const DataLayout &DL,			evaluateBitcastFromPtr(Constant *Ptr, const DataLayout &DL,
	const TargetLibraryInfo *TLI,			const TargetLibraryInfo *TLI,
	std::function<Constant (Constant )> Func) {			std::function<Constant (Constant )> Func) {
	Constant *Val;			Constant *Val;
	while (!(Val = Func(Ptr))) {			while (!(Val = Func(Ptr))) {
	// If Ty is a struct, we can convert the pointer to the struct			// If Ty is a non-opaque struct, we can convert the pointer to the struct
	// into a pointer to its first member.			// into a pointer to its first member.
	// FIXME: This could be extended to support arrays as well.			// FIXME: This could be extended to support arrays as well.
	Type *Ty = cast<PointerType>(Ptr->getType())->getElementType();			Type *Ty = cast<PointerType>(Ptr->getType())->getElementType();
	if (!isa<StructType>(Ty))			if (!isa<StructType>(Ty) \|\| cast<StructType>(Ty)->isOpaque())
				echristoUnsubmitted Done Reply Inline Actions You have a dyn_cast here that is immediately dereferenced rather than checked. Might be better to just cast (since we know it's a StructType) or dyn_cast outside of the if? echristo: You have a dyn_cast here that is immediately dereferenced rather than checked. Might be better…
	break;			break;

	IntegerType *IdxTy = IntegerType::get(Ty->getContext(), 32);			IntegerType *IdxTy = IntegerType::get(Ty->getContext(), 32);
	Constant *IdxZero = ConstantInt::get(IdxTy, 0, false);			Constant *IdxZero = ConstantInt::get(IdxTy, 0, false);
	Constant *const IdxList[] = {IdxZero, IdxZero};			Constant *const IdxList[] = {IdxZero, IdxZero};

	Ptr = ConstantExpr::getGetElementPtr(Ty, Ptr, IdxList);			Ptr = ConstantExpr::getGetElementPtr(Ty, Ptr, IdxList);
	Ptr = ConstantFoldConstant(Ptr, DL, TLI);			Ptr = ConstantFoldConstant(Ptr, DL, TLI);
	▲ Show 20 Lines • Show All 534 Lines • Show Last 20 Lines

llvm/test/Transforms/GlobalOpt/evaluate-bitcast-4.ll

This file was added.

				; PR48055. Check that this does not crash.
				; RUN: opt -globalopt %s -disable-output
				target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
				target triple = "x86_64-unknown-linux-gnu"

				%struct.g = type opaque
				%struct.a = type { i32 (...)** }

				@l = dso_local global i32 0, align 4
				@h = external dso_local global %struct.g, align 1
				@llvm.global_ctors = appending global [1 x { i32, void (), i8 }] [{ i32, void (), i8 } { i32 65535, void ()* @_GLOBAL__sub_I_bug48055.cc, i8* null }]

				; Function Attrs: uwtable
				define internal void @__cxx_global_var_init() {
				entry:
				%vtable = load i32 (%struct.a), i32 (%struct.a)*** bitcast (%struct.g* @h to i32 (%struct.a)**), align 1
				%0 = load i32 (%struct.a), i32 (%struct.a)* %vtable, align 8
				%call = call i32 %0(%struct.a* nonnull dereferenceable(8) bitcast (%struct.g* @h to %struct.a*))
				store i32 %call, i32* @l, align 4
				ret void
				}

				; Function Attrs: uwtable
				define internal void @_GLOBAL__sub_I_bug48055.cc() {
				entry:
				call void @__cxx_global_var_init()
				ret void
				}

This is an archive of the discontinued LLVM Phabricator instance.

Fix for Bug 48055.ClosedPublic

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Diff 309576

llvm/lib/Transforms/Utils/Evaluator.cpp

llvm/test/Transforms/GlobalOpt/evaluate-bitcast-4.ll

Fix for Bug 48055.
ClosedPublic