Skip to content

Commit

Permalink
Fix Objective-C++ Sret of non-trivial data types on Windows ARM64 (ll…
Browse files Browse the repository at this point in the history
…vm#88671)

Linked to gnustep/libobjc2#289.

More information can be found in issue: llvm#88273.

My solution involves creating a new message-send function for this
calling convention when targeting MSVC. Additional information is
available in the libobjc2 pull request.

I am unsure whether we should check for a runtime version where
objc_msgSend_stret2_np is guaranteed to be present or leave it as is,
considering it remains a critical bug. What are your thoughts about this
@davidchisnall?

(cherry picked from commit 3dcd2cc)
  • Loading branch information
hmelder authored and tstellar committed Apr 29, 2024
1 parent 6dbaa89 commit ee5bb0c
Show file tree
Hide file tree
Showing 4 changed files with 105 additions and 14 deletions.
5 changes: 5 additions & 0 deletions clang/lib/CodeGen/CGCall.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -1581,6 +1581,11 @@ bool CodeGenModule::ReturnTypeUsesSRet(const CGFunctionInfo &FI) {
return RI.isIndirect() || (RI.isInAlloca() && RI.getInAllocaSRet());
}

bool CodeGenModule::ReturnTypeHasInReg(const CGFunctionInfo &FI) {
const auto &RI = FI.getReturnInfo();
return RI.getInReg();
}

bool CodeGenModule::ReturnSlotInterferesWithArgs(const CGFunctionInfo &FI) {
return ReturnTypeUsesSRet(FI) &&
getTargetCodeGenInfo().doesReturnSlotInterfereWithArgs();
Expand Down
34 changes: 20 additions & 14 deletions clang/lib/CodeGen/CGObjCGNU.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -2903,23 +2903,29 @@ CGObjCGNU::GenerateMessageSend(CodeGenFunction &CGF,
break;
case CodeGenOptions::Mixed:
case CodeGenOptions::NonLegacy:
StringRef name = "objc_msgSend";
if (CGM.ReturnTypeUsesFPRet(ResultType)) {
imp =
CGM.CreateRuntimeFunction(llvm::FunctionType::get(IdTy, IdTy, true),
"objc_msgSend_fpret")
.getCallee();
name = "objc_msgSend_fpret";
} else if (CGM.ReturnTypeUsesSRet(MSI.CallInfo)) {
// The actual types here don't matter - we're going to bitcast the
// function anyway
imp =
CGM.CreateRuntimeFunction(llvm::FunctionType::get(IdTy, IdTy, true),
"objc_msgSend_stret")
.getCallee();
} else {
imp = CGM.CreateRuntimeFunction(
llvm::FunctionType::get(IdTy, IdTy, true), "objc_msgSend")
.getCallee();
name = "objc_msgSend_stret";

// The address of the memory block is be passed in x8 for POD type,
// or in x0 for non-POD type (marked as inreg).
bool shouldCheckForInReg =
CGM.getContext()
.getTargetInfo()
.getTriple()
.isWindowsMSVCEnvironment() &&
CGM.getContext().getTargetInfo().getTriple().isAArch64();
if (shouldCheckForInReg && CGM.ReturnTypeHasInReg(MSI.CallInfo)) {
name = "objc_msgSend_stret2";
}
}
// The actual types here don't matter - we're going to bitcast the
// function anyway
imp = CGM.CreateRuntimeFunction(llvm::FunctionType::get(IdTy, IdTy, true),
name)
.getCallee();
}

// Reset the receiver in case the lookup modified it
Expand Down
3 changes: 3 additions & 0 deletions clang/lib/CodeGen/CodeGenModule.h
Original file line number Diff line number Diff line change
Expand Up @@ -1239,6 +1239,9 @@ class CodeGenModule : public CodeGenTypeCache {
/// Return true iff the given type uses 'sret' when used as a return type.
bool ReturnTypeUsesSRet(const CGFunctionInfo &FI);

/// Return true iff the given type has `inreg` set.
bool ReturnTypeHasInReg(const CGFunctionInfo &FI);

/// Return true iff the given type uses an argument slot when 'sret' is used
/// as a return type.
bool ReturnSlotInterferesWithArgs(const CGFunctionInfo &FI);
Expand Down
77 changes: 77 additions & 0 deletions clang/test/CodeGenObjCXX/msabi-stret-arm64.mm
Original file line number Diff line number Diff line change
@@ -0,0 +1,77 @@
// RUN: %clang_cc1 -triple aarch64-pc-windows-msvc -fobjc-runtime=gnustep-2.2 -fobjc-dispatch-method=non-legacy -emit-llvm -o - %s | FileCheck %s

// Pass and return for type size <= 8 bytes.
struct S1 {
int a[2];
};

// Pass and return hfa <= 8 bytes
struct F1 {
float a[2];
};

// Pass and return for type size > 16 bytes.
struct S2 {
int a[5];
};

// Pass and return aggregate (of size < 16 bytes) with non-trivial destructor.
// Sret and inreg: Returned in x0
struct S3 {
int a[3];
~S3();
};
S3::~S3() {
}


@interface MsgTest { id isa; } @end
@implementation MsgTest
- (S1) smallS1 {
S1 x;
x.a[0] = 0;
x.a[1] = 1;
return x;

}
- (F1) smallF1 {
F1 x;
x.a[0] = 0.2f;
x.a[1] = 0.5f;
return x;
}
- (S2) stretS2 {
S2 x;
for (int i = 0; i < 5; i++) {
x.a[i] = i;
}
return x;
}
- (S3) stretInRegS3 {
S3 x;
for (int i = 0; i < 3; i++) {
x.a[i] = i;
}
return x;
}
+ (S3) msgTestStretInRegS3 {
S3 x;
for (int i = 0; i < 3; i++) {
x.a[i] = i;
}
return x;
}
@end

void test0(MsgTest *t) {
// CHECK: call {{.*}} @objc_msgSend
S1 ret = [t smallS1];
// CHECK: call {{.*}} @objc_msgSend
F1 ret2 = [t smallF1];
// CHECK: call {{.*}} @objc_msgSend_stret
S2 ret3 = [t stretS2];
// CHECK: call {{.*}} @objc_msgSend_stret2
S3 ret4 = [t stretInRegS3];
// CHECK: call {{.*}} @objc_msgSend_stret2
S3 ret5 = [MsgTest msgTestStretInRegS3];
}

0 comments on commit ee5bb0c

Please sign in to comment.