mstorsjo updated this revision to Diff 549517.
mstorsjo added a comment.
Updated to just check isEmptyRecord in EmitCall.
The second part of the test probably is kinda redundant/pointless at this
point, and I guess the test comment needs updating too; can do that later when
the implementation is fine.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D157332/new/
https://reviews.llvm.org/D157332
Files:
clang/lib/CodeGen/CGCall.cpp
clang/test/CodeGenCXX/ctor-empty-nounique.cpp
Index: clang/test/CodeGenCXX/ctor-empty-nounique.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/ctor-empty-nounique.cpp
@@ -0,0 +1,43 @@
+// RUN: %clang_cc1 -triple x86_64-windows-gnu -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple powerpc64le-windows-gnu -emit-llvm -o - %s |
FileCheck %s
+
+// An empty struct is handled as a struct with a dummy i8, on all targets.
+// Most targets treat an empty struct return value as essentially void - but
+// some don't. (Currently, at least x86_64-windows-* and powerpc64le-* don't
+// treat it as void.)
+//
+// When intializing a struct with such a no_unique_address member, make sure we
+// don't write the dummy i8 into the struct where there's no space allocated
for
+// it.
+//
+// This can only be tested with targets that don't treat empty struct returns
as
+// void.
+
+struct S {};
+S f();
+struct Z {
+ int x;
+ [[no_unique_address]] S y;
+ Z();
+};
+Z::Z() : x(111), y(f()) {}
+
+// CHECK: define {{.*}} @_ZN1ZC2Ev
+// CHECK: %call = call i8 @_Z1fv()
+// CHECK-NEXT: ret void
+
+struct S2 {
+ S2();
+};
+struct Z2 {
+ int x;
+ [[no_unique_address]] S2 y;
+ Z2();
+};
+Z2::Z2() : x(111) {}
+
+// CHECK: define {{.*}} @_ZN2Z2C2Ev(ptr {{.*}} %this)
+// CHECK: %this.addr = alloca ptr
+// CHECK: store ptr %this, ptr %this.addr
+// CHECK: %this1 = load ptr, ptr %this.addr
+// CHECK: call void @_ZN2S2C1Ev(ptr {{.*}} %this1)
Index: clang/lib/CodeGen/CGCall.cpp
===================================================================
--- clang/lib/CodeGen/CGCall.cpp
+++ clang/lib/CodeGen/CGCall.cpp
@@ -13,6 +13,7 @@
#include "CGCall.h"
#include "ABIInfo.h"
+#include "ABIInfoImpl.h"
#include "CGBlocks.h"
#include "CGCXXABI.h"
#include "CGCleanup.h"
@@ -5778,8 +5779,10 @@
}
// If the value is offset in memory, apply the offset now.
- Address StorePtr = emitAddressAtOffset(*this, DestPtr, RetAI);
- CreateCoercedStore(CI, StorePtr, DestIsVolatile, *this);
+ if (!isEmptyRecord(getContext(), RetTy, true)) {
+ Address StorePtr = emitAddressAtOffset(*this, DestPtr, RetAI);
+ CreateCoercedStore(CI, StorePtr, DestIsVolatile, *this);
+ }
return convertTempToRValue(DestPtr, RetTy, SourceLocation());
}
Index: clang/test/CodeGenCXX/ctor-empty-nounique.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/ctor-empty-nounique.cpp
@@ -0,0 +1,43 @@
+// RUN: %clang_cc1 -triple x86_64-windows-gnu -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple powerpc64le-windows-gnu -emit-llvm -o - %s | FileCheck %s
+
+// An empty struct is handled as a struct with a dummy i8, on all targets.
+// Most targets treat an empty struct return value as essentially void - but
+// some don't. (Currently, at least x86_64-windows-* and powerpc64le-* don't
+// treat it as void.)
+//
+// When intializing a struct with such a no_unique_address member, make sure we
+// don't write the dummy i8 into the struct where there's no space allocated for
+// it.
+//
+// This can only be tested with targets that don't treat empty struct returns as
+// void.
+
+struct S {};
+S f();
+struct Z {
+ int x;
+ [[no_unique_address]] S y;
+ Z();
+};
+Z::Z() : x(111), y(f()) {}
+
+// CHECK: define {{.*}} @_ZN1ZC2Ev
+// CHECK: %call = call i8 @_Z1fv()
+// CHECK-NEXT: ret void
+
+struct S2 {
+ S2();
+};
+struct Z2 {
+ int x;
+ [[no_unique_address]] S2 y;
+ Z2();
+};
+Z2::Z2() : x(111) {}
+
+// CHECK: define {{.*}} @_ZN2Z2C2Ev(ptr {{.*}} %this)
+// CHECK: %this.addr = alloca ptr
+// CHECK: store ptr %this, ptr %this.addr
+// CHECK: %this1 = load ptr, ptr %this.addr
+// CHECK: call void @_ZN2S2C1Ev(ptr {{.*}} %this1)
Index: clang/lib/CodeGen/CGCall.cpp
===================================================================
--- clang/lib/CodeGen/CGCall.cpp
+++ clang/lib/CodeGen/CGCall.cpp
@@ -13,6 +13,7 @@
#include "CGCall.h"
#include "ABIInfo.h"
+#include "ABIInfoImpl.h"
#include "CGBlocks.h"
#include "CGCXXABI.h"
#include "CGCleanup.h"
@@ -5778,8 +5779,10 @@
}
// If the value is offset in memory, apply the offset now.
- Address StorePtr = emitAddressAtOffset(*this, DestPtr, RetAI);
- CreateCoercedStore(CI, StorePtr, DestIsVolatile, *this);
+ if (!isEmptyRecord(getContext(), RetTy, true)) {
+ Address StorePtr = emitAddressAtOffset(*this, DestPtr, RetAI);
+ CreateCoercedStore(CI, StorePtr, DestIsVolatile, *this);
+ }
return convertTempToRValue(DestPtr, RetTy, SourceLocation());
}
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