[llvm] 5f491a4 - [LLVMABI] Create a skeleton for AArch64 ABI handling (#216222)
via llvm-commits
llvm-commits at lists.llvm.org
Fri Aug 14 16:56:51 PDT 2026
Author: Andy Kaylor
Date: 2026-08-14T16:56:45-07:00
New Revision: 5f491a454cb855179295c0463622393df0c5bb42
URL: https://github.com/llvm/llvm-project/commit/5f491a454cb855179295c0463622393df0c5bb42
DIFF: https://github.com/llvm/llvm-project/commit/5f491a454cb855179295c0463622393df0c5bb42.diff
LOG: [LLVMABI] Create a skeleton for AArch64 ABI handling (#216222)
This change adds the most basic implementation of llvm::abi::TargetInfo
for AArch64 targets and establishes a unit test for it.
There was no isolated testing for previous targets implemented in the
ABI library. They were only tested through clang. My plan with AArch64
is to create unit tests so that the library can be tested without
building the clang target, but also to have clang tests so that the
handling can be compared to clang's ABI handling as a meaningful point
of reference for correct behavior.
For this initial change, because no real handling is implemented yet, I
am not introducing the clang hook or any clang-based tests.
Assisted-by: Cursor / Grok 4.5 (test generation)
Added:
llvm/lib/ABI/Targets/AArch64.cpp
llvm/unittests/ABI/AArch64TargetInfoTest.cpp
llvm/unittests/ABI/CMakeLists.txt
Modified:
llvm/include/llvm/ABI/TargetInfo.h
llvm/lib/ABI/CMakeLists.txt
llvm/unittests/CMakeLists.txt
Removed:
################################################################################
diff --git a/llvm/include/llvm/ABI/TargetInfo.h b/llvm/include/llvm/ABI/TargetInfo.h
index 101ba88e9a4ea..4ed28be292ba6 100644
--- a/llvm/include/llvm/ABI/TargetInfo.h
+++ b/llvm/include/llvm/ABI/TargetInfo.h
@@ -98,6 +98,16 @@ LLVM_ABI std::unique_ptr<TargetInfo>
createX86_64TargetInfo(TypeBuilder &TB, X86AVXABILevel AVXLevel,
bool Has64BitPointers, const ABICompatInfo &Compat);
+enum class AArch64ABIKind {
+ AAPCS = 0,
+ DarwinPCS,
+ Win64,
+ AAPCSSoft,
+};
+
+LLVM_ABI std::unique_ptr<TargetInfo>
+createAArch64TargetInfo(TypeBuilder &TB, AArch64ABIKind Kind);
+
} // namespace abi
} // namespace llvm
diff --git a/llvm/lib/ABI/CMakeLists.txt b/llvm/lib/ABI/CMakeLists.txt
index 47ce5926e6039..39e725ca9fd3b 100644
--- a/llvm/lib/ABI/CMakeLists.txt
+++ b/llvm/lib/ABI/CMakeLists.txt
@@ -3,6 +3,7 @@ add_llvm_component_library(LLVMABI
FunctionInfo.cpp
TargetInfo.cpp
IRTypeMapper.cpp
+ Targets/AArch64.cpp
Targets/BPF.cpp
Targets/X86.cpp
diff --git a/llvm/lib/ABI/Targets/AArch64.cpp b/llvm/lib/ABI/Targets/AArch64.cpp
new file mode 100644
index 0000000000000..d26dec1ad3a0b
--- /dev/null
+++ b/llvm/lib/ABI/Targets/AArch64.cpp
@@ -0,0 +1,41 @@
+//===- AArch64.cpp - AArch64 ABI Implementation ---------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ABI/FunctionInfo.h"
+#include "llvm/ABI/TargetInfo.h"
+#include "llvm/ABI/Types.h"
+#include "llvm/Support/ErrorHandling.h"
+
+namespace llvm {
+namespace abi {
+
+class AArch64TargetInfo : public TargetInfo {
+public:
+ AArch64TargetInfo(TypeBuilder &TB, AArch64ABIKind Kind)
+ : TB(TB), Kind(Kind) {}
+
+ void computeInfo(FunctionInfo &FI) const override {
+ FI.getReturnInfo() = ArgInfo::getDirect();
+ for (auto &I : FI.arguments())
+ I.Info = ArgInfo::getDirect();
+ }
+
+private:
+ [[maybe_unused]] TypeBuilder &TB;
+ [[maybe_unused]] AArch64ABIKind Kind;
+};
+
+std::unique_ptr<TargetInfo> createAArch64TargetInfo(TypeBuilder &TB,
+ AArch64ABIKind Kind) {
+ if (Kind == AArch64ABIKind::Win64)
+ llvm_unreachable("Win64 ABI not supported yet");
+ return std::make_unique<AArch64TargetInfo>(TB, Kind);
+}
+
+} // namespace abi
+} // namespace llvm
diff --git a/llvm/unittests/ABI/AArch64TargetInfoTest.cpp b/llvm/unittests/ABI/AArch64TargetInfoTest.cpp
new file mode 100644
index 0000000000000..0f4326b9d4d01
--- /dev/null
+++ b/llvm/unittests/ABI/AArch64TargetInfoTest.cpp
@@ -0,0 +1,94 @@
+//===- AArch64TargetInfoTest.cpp - AArch64 ABI unit tests -----------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ABI/FunctionInfo.h"
+#include "llvm/ABI/TargetInfo.h"
+#include "llvm/ABI/Types.h"
+#include "llvm/ADT/APFloat.h"
+#include "llvm/IR/CallingConv.h"
+#include "llvm/Support/Alignment.h"
+#include "llvm/Support/Allocator.h"
+#include "gtest/gtest.h"
+
+namespace {
+
+using ABIType = llvm::abi::Type;
+using llvm::abi::AArch64ABIKind;
+using llvm::abi::ArgEntry;
+using llvm::abi::ArgInfo;
+using llvm::abi::createAArch64TargetInfo;
+using llvm::abi::FunctionInfo;
+using llvm::abi::TargetInfo;
+using llvm::abi::TypeBuilder;
+
+class AArch64TargetInfoTest : public ::testing::Test {
+protected:
+ llvm::BumpPtrAllocator Alloc;
+ TypeBuilder TB;
+ const ABIType *I32;
+ const ABIType *F64;
+ const ABIType *Ptr;
+ const ABIType *Void;
+
+ AArch64TargetInfoTest()
+ : TB(Alloc), I32(TB.getIntegerType(32, llvm::Align(4), /*Signed=*/true)),
+ F64(TB.getFloatType(llvm::APFloat::IEEEdouble(), llvm::Align(8))),
+ Ptr(TB.getPointerType(64, llvm::Align(8))), Void(TB.getVoidType()) {}
+};
+
+static void expectAllDirect(const FunctionInfo &FI) {
+ EXPECT_TRUE(FI.getReturnInfo().isDirect());
+ EXPECT_EQ(FI.getReturnInfo().getCoerceToType(), nullptr);
+ for (const ArgEntry &Arg : FI.arguments()) {
+ EXPECT_TRUE(Arg.Info.isDirect());
+ EXPECT_EQ(Arg.Info.getCoerceToType(), nullptr);
+ }
+}
+
+TEST_F(AArch64TargetInfoTest, ComputeInfoMarksReturnAndArgsDirect) {
+ std::unique_ptr<TargetInfo> TI =
+ createAArch64TargetInfo(TB, AArch64ABIKind::AAPCS);
+ std::unique_ptr<FunctionInfo> FI =
+ FunctionInfo::create(llvm::CallingConv::C, I32, {I32, F64, Ptr});
+
+ // Poison the defaults so a no-op would fail the assertions below.
+ FI->getReturnInfo() = ArgInfo::getIgnore();
+ for (ArgEntry &Arg : FI->arguments())
+ Arg.Info = ArgInfo::getIgnore();
+
+ TI->computeInfo(*FI);
+ expectAllDirect(*FI);
+}
+
+TEST_F(AArch64TargetInfoTest, ComputeInfoVoidReturnNoArgs) {
+ std::unique_ptr<TargetInfo> TI =
+ createAArch64TargetInfo(TB, AArch64ABIKind::DarwinPCS);
+ std::unique_ptr<FunctionInfo> FI =
+ FunctionInfo::create(llvm::CallingConv::C, Void, {});
+
+ FI->getReturnInfo() = ArgInfo::getIgnore();
+ TI->computeInfo(*FI);
+
+ EXPECT_TRUE(FI->getReturnInfo().isDirect());
+ EXPECT_TRUE(FI->arguments().empty());
+}
+
+TEST_F(AArch64TargetInfoTest, ComputeInfoAAPCSSoftSameAsStub) {
+ std::unique_ptr<TargetInfo> TI =
+ createAArch64TargetInfo(TB, AArch64ABIKind::AAPCSSoft);
+ std::unique_ptr<FunctionInfo> FI =
+ FunctionInfo::create(llvm::CallingConv::C, F64, {I32});
+
+ FI->getReturnInfo() = ArgInfo::getIgnore();
+ FI->getArgInfo(0).Info = ArgInfo::getIgnore();
+
+ TI->computeInfo(*FI);
+ expectAllDirect(*FI);
+}
+
+} // namespace
diff --git a/llvm/unittests/ABI/CMakeLists.txt b/llvm/unittests/ABI/CMakeLists.txt
new file mode 100644
index 0000000000000..fe0431524c7c2
--- /dev/null
+++ b/llvm/unittests/ABI/CMakeLists.txt
@@ -0,0 +1,9 @@
+set(LLVM_LINK_COMPONENTS
+ ABI
+ Core
+ Support
+ )
+
+add_llvm_unittest(ABITests
+ AArch64TargetInfoTest.cpp
+ )
diff --git a/llvm/unittests/CMakeLists.txt b/llvm/unittests/CMakeLists.txt
index 5d507d577bb94..c6ce09b3d67f2 100644
--- a/llvm/unittests/CMakeLists.txt
+++ b/llvm/unittests/CMakeLists.txt
@@ -28,6 +28,7 @@ if (CMAKE_COMPILER_IS_GNUCXX)
list(APPEND LLVM_COMPILE_FLAGS "-Wno-dangling-else")
endif ()
+add_subdirectory(ABI)
add_subdirectory(ADT)
add_subdirectory(Analysis)
add_subdirectory(AsmParser)
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