erichkeane created this revision.
erichkeane added reviewers: rnk, pcc.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.
r369697 changed the behavior of stripPointerCasts to no longer include
aliases. However, the code in CGDeclCXX.cpp's createAtExitStub counted
on the looking through aliases to properly set the calling convention of
a call.
The result of the change was that the calling convention mismatch of the
call would be replaced with a llvm.trap, causing a runtime crash.
https://reviews.llvm.org/D68584
Files:
clang/lib/CodeGen/CGDeclCXX.cpp
clang/test/CodeGenCXX/call-conv-thru-alias.cpp
llvm/include/llvm/IR/Value.h
llvm/lib/IR/Value.cpp
Index: llvm/lib/IR/Value.cpp
===================================================================
--- llvm/lib/IR/Value.cpp
+++ llvm/lib/IR/Value.cpp
@@ -455,6 +455,7 @@
// Various metrics for how much to strip off of pointers.
enum PointerStripKind {
PSK_ZeroIndices,
+ PSK_ZeroIndicesAndAliases,
PSK_ZeroIndicesSameRepresentation,
PSK_ZeroIndicesAndInvariantGroups,
PSK_InBoundsConstantIndices,
@@ -475,6 +476,7 @@
if (auto *GEP = dyn_cast<GEPOperator>(V)) {
switch (StripKind) {
case PSK_ZeroIndices:
+ case PSK_ZeroIndicesAndAliases:
case PSK_ZeroIndicesSameRepresentation:
case PSK_ZeroIndicesAndInvariantGroups:
if (!GEP->hasAllZeroIndices())
@@ -497,6 +499,8 @@
// TODO: If we know an address space cast will not change the
// representation we could look through it here as well.
V = cast<Operator>(V)->getOperand(0);
+ } else if (StripKind == PSK_ZeroIndicesAndAliases && isa<GlobalAlias>(V)) {
+ V = cast<GlobalAlias>(V)->getAliasee();
} else {
if (const auto *Call = dyn_cast<CallBase>(V)) {
if (const Value *RV = Call->getReturnedArgOperand()) {
@@ -526,6 +530,10 @@
return stripPointerCastsAndOffsets<PSK_ZeroIndices>(this);
}
+const Value *Value::stripPointerCastsAndAliases() const {
+ return stripPointerCastsAndOffsets<PSK_ZeroIndicesAndAliases>(this);
+}
+
const Value *Value::stripPointerCastsSameRepresentation() const {
return stripPointerCastsAndOffsets<PSK_ZeroIndicesSameRepresentation>(this);
}
Index: llvm/include/llvm/IR/Value.h
===================================================================
--- llvm/include/llvm/IR/Value.h
+++ llvm/include/llvm/IR/Value.h
@@ -523,6 +523,16 @@
static_cast<const Value *>(this)->stripPointerCasts());
}
+ /// Strip off pointer casts, all-zero GEPs, address space casts, and aliases.
+ ///
+ /// Returns the original uncasted value. If this is called on a non-pointer
+ /// value, it returns 'this'.
+ const Value *stripPointerCastsAndAliases() const;
+ Value *stripPointerCastsAndAliases() {
+ return const_cast<Value *>(
+ static_cast<const Value *>(this)->stripPointerCastsAndAliases());
+ }
+
/// Strip off pointer casts, all-zero GEPs and address space casts
/// but ensures the representation of the result stays the same.
///
Index: clang/test/CodeGenCXX/call-conv-thru-alias.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/call-conv-thru-alias.cpp
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -triple i686-windows-pc -emit-llvm -o - -mconstructor-aliases -O1 -disable-llvm-passes %s | FileCheck %s
+
+struct Base { virtual ~Base(); };
+struct Derived : Base {
+ virtual ~Derived();
+ static Derived inst;
+};
+
+Base::~Base(){}
+Derived::~Derived(){}
+Derived Derived::inst;
+
+// CHECK: @"??1Derived@@UAE@XZ" = dso_local unnamed_addr alias void (%struct.Derived*), bitcast (void (%struct.Base*)* @"??1Base@@UAE@XZ" to void (%struct.Derived*)*)
+
+// CHECK: define dso_local x86_thiscallcc void @"??1Base@@UAE@XZ"
+// CHECK: define internal void @"??__E?inst@Derived@@2U1@A@@YAXXZ"
+// CHECK: call i32 @atexit(void ()* @"??__F?inst@Derived@@2U1@A@@YAXXZ"
+//
+// CHECK: define internal void @"??__F?inst@Derived@@2U1@A@@YAXXZ"
+// CHECK-NEXT: entry:
+// CHECK-NEXT: call x86_thiscallcc void @"??1Derived@@UAE@XZ"
Index: clang/lib/CodeGen/CGDeclCXX.cpp
===================================================================
--- clang/lib/CodeGen/CGDeclCXX.cpp
+++ clang/lib/CodeGen/CGDeclCXX.cpp
@@ -248,8 +248,8 @@
llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
// Make sure the call and the callee agree on calling convention.
- if (llvm::Function *dtorFn =
- dyn_cast<llvm::Function>(dtor.getCallee()->stripPointerCasts()))
+ if (llvm::Function *dtorFn = dyn_cast<llvm::Function>(
+ dtor.getCallee()->stripPointerCastsAndAliases()))
call->setCallingConv(dtorFn->getCallingConv());
CGF.FinishFunction();
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