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[MS ABI]: Support preserve_none in MS ABI #96487

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Merged
merged 2 commits into from
Jun 26, 2024
Merged

[MS ABI]: Support preserve_none in MS ABI #96487

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1e95098
[MS ABI]: Support preserve_none in MS ABI
antangelo Jun 24, 2024
2f08dfb
Emit error instead of abort on unsupported calling convention in Micr…
antangelo Jun 26, 2024
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8 changes: 7 additions & 1 deletion clang/lib/AST/MicrosoftMangle.cpp
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Expand Up @@ -2962,7 +2962,10 @@ void MicrosoftCXXNameMangler::mangleCallingConvention(CallingConv CC) {
// ::= J # __export __fastcall
// ::= Q # __vectorcall
// ::= S # __attribute__((__swiftcall__)) // Clang-only
// ::= T # __attribute__((__swiftasynccall__))
// ::= W # __attribute__((__swiftasynccall__))
// ::= U # __attribute__((__preserve_most__))
// ::= V # __attribute__((__preserve_none__)) //
// Clang-only
// // Clang-only
// ::= w # __regcall
// ::= x # __regcall4
Expand All @@ -2986,6 +2989,9 @@ void MicrosoftCXXNameMangler::mangleCallingConvention(CallingConv CC) {
case CC_Swift: Out << 'S'; break;
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The default case here should be a proper compiler error, not an unreachable, since there's no good way to prevent arbitrary calling conventions from reaching the mangler.

If you search this file, you can find examples of "cannot yet mangle". Please copy that error handling pattern and use it in the default case for this switch to improve handling of cases like this in the future.

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Done

case CC_SwiftAsync: Out << 'W'; break;
case CC_PreserveMost: Out << 'U'; break;
case CC_PreserveNone:
Out << 'V';
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This is not a good long term solution. I emailed the relevant external Microsoft mailing list for discussing these issues and CC'd some folks to inquire about a better long term solution, but we can continue with this approach for now.

break;
case CC_X86RegCall:
if (getASTContext().getLangOpts().RegCall4)
Out << "x";
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1 change: 1 addition & 0 deletions clang/lib/Basic/Targets/AArch64.cpp
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Expand Up @@ -1536,6 +1536,7 @@ WindowsARM64TargetInfo::checkCallingConvention(CallingConv CC) const {
case CC_OpenCLKernel:
case CC_PreserveMost:
case CC_PreserveAll:
case CC_PreserveNone:
case CC_Swift:
case CC_SwiftAsync:
case CC_Win64:
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28 changes: 28 additions & 0 deletions clang/test/CodeGenCXX/msabi-preserve-none-cc.cpp
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@@ -0,0 +1,28 @@
// RUN: %clang_cc1 -triple x86_64-unknown-windows-msvc -fdeclspec -emit-llvm %s -o - | FileCheck %s
// RUN: %clang_cc1 -triple aarch64-unknown-windows-msvc -fdeclspec -emit-llvm %s -o - | FileCheck %s

void __attribute__((__preserve_none__)) f() {}
// CHECK-DAG: @"?f@@YVXXZ"

void (__attribute__((__preserve_none__)) *p)();
// CHECK-DAG: @"?p@@3P6VXXZEA

namespace {
void __attribute__((__preserve_none__)) __attribute__((__used__)) f() { }
}
// CHECK-DAG: @"?f@?A0x{{[^@]*}}@@YVXXZ"

namespace n {
void __attribute__((__preserve_none__)) f() {}
}
// CHECK-DAG: @"?f@n@@YVXXZ"

struct __declspec(dllexport) S {
S(const S &) = delete;
S & operator=(const S &) = delete;
void __attribute__((__preserve_none__)) m() { }
};
// CHECK-DAG: @"?m@S@@QEAVXXZ"

void f(void (__attribute__((__preserve_none__))())) {}
// CHECK-DAG: @"?f@@YAXP6VXXZ@Z"
1 change: 1 addition & 0 deletions clang/test/Sema/preserve-none-call-conv.c
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@@ -1,4 +1,5 @@
// RUN: %clang_cc1 %s -fsyntax-only -triple x86_64-unknown-unknown -verify
// RUN: %clang_cc1 %s -fsyntax-only -triple aarch64-unknown-unknown -verify

typedef void typedef_fun_t(int);

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