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[flang] Use correct int extension flags for C-ABI calls on aarch64 #137105

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Apr 25, 2025
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[flang] Use correct int extension flags for C-ABI calls on aarch64 #137105

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[flang] Use correct int extension flags for C-ABI calls on aarch64
ashermancinelli Apr 23, 2025
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ashermancinelli Apr 24, 2025
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30 changes: 29 additions & 1 deletion flang/lib/Optimizer/CodeGen/Target.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -784,7 +784,7 @@ struct TargetX86_64Win : public GenericTarget<TargetX86_64Win> {
} // namespace

//===----------------------------------------------------------------------===//
// AArch64 linux target specifics.
// AArch64 target specifics.
//===----------------------------------------------------------------------===//

namespace {
Expand All @@ -810,6 +810,34 @@ struct TargetAArch64 : public GenericTarget<TargetAArch64> {
return marshal;
}

CodeGenSpecifics::Marshalling
integerArgumentType(mlir::Location loc,
mlir::IntegerType argTy) const override {
if (argTy.getWidth() < getCIntTypeWidth() && argTy.isSignless()) {
AT::IntegerExtension intExt;
if (argTy.getWidth() == 1) {
// Zero extend for 'i1'.
intExt = AT::IntegerExtension::Zero;
} else {
if (triple.isOSDarwin()) {
// On Darwin, sign extend. The apple developer guide specifies this as
// a divergence from the AArch64PCS:
// https://developer.apple.com/documentation/xcode/writing-arm64-code-for-apple-platforms#Pass-arguments-to-functions-correctly
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Does it talk only about arguments and not return values?

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The apple dev guide does not mention sign/zero extension of returned integers, as far as I can tell. The aa64pcs explains that register types ought to be handled the same way, whether passed or returned:

The manner in which a result is returned from a function is determined by the type of that result:

If the type, T, of the result of a function is such that

void func(T arg)
would require that arg be passed as a value in a register (or set of registers) according to the rules in Parameter passing, then the result is returned in the same registers as would be used for such an argument.

Otherwise, the caller shall reserve a block of memory of sufficient size and alignment to hold the result. The address of the memory block shall be passed as an additional argument to the function in x8. The callee may modify the result memory block at any point during the execution of the subroutine (there is no requirement for the callee to preserve the value stored in x8).

Clang does the same sign/zero extension for the return type, which is what I used as my guide. I wouldn't mind if the apple dev guide were updated to explicitly say one way or the other, though.

intExt = AT::IntegerExtension::Sign;
} else {
// On linux, pass directly and do not extend.
intExt = AT::IntegerExtension::None;
}
}
CodeGenSpecifics::Marshalling marshal;
marshal.emplace_back(argTy, AT{/*alignment=*/0, /*byval=*/false,
/*sret=*/false, /*append=*/false,
/*intExt=*/intExt});
return marshal;
}
return GenericTarget::integerArgumentType(loc, argTy);
}

CodeGenSpecifics::Marshalling
complexReturnType(mlir::Location loc, mlir::Type eleTy) const override {
CodeGenSpecifics::Marshalling marshal;
Expand Down
2 changes: 1 addition & 1 deletion flang/test/Fir/convert-to-llvm-target.fir
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@@ -1,7 +1,7 @@
// RUN: fir-opt --split-input-file --fir-to-llvm-ir="target=x86_64-unknown-linux-gnu" %s | FileCheck %s --check-prefix INT64
// RUN: fir-opt --split-input-file --fir-to-llvm-ir="target=aarch64-unknown-linux-gnu" %s | FileCheck %s --check-prefixes INT64
// RUN: fir-opt --split-input-file --fir-to-llvm-ir="target=i386-unknown-linux-gnu" %s | FileCheck %s --check-prefixes INT32
// RUN: fir-opt --split-input-file --fir-to-llvm-ir="target=powerpc64le-unknown-linux-gn" %s | FileCheck %s --check-prefixes INT64
// RUN: fir-opt --split-input-file --fir-to-llvm-ir="target=powerpc64le-unknown-linux-gnu" %s | FileCheck %s --check-prefixes INT64

//=============================================================================
// SUMMARY: Tests for FIR --> LLVM MLIR conversion that *depend* on the target
Expand Down
21 changes: 19 additions & 2 deletions flang/test/Fir/target-rewrite-integer.fir
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@@ -1,6 +1,8 @@
// RUN: fir-opt --split-input-file --target-rewrite="target=i386-unknown-linux-gnu" %s | FileCheck %s --check-prefixes=I32,ALL
// RUN: fir-opt --split-input-file --target-rewrite="target=x86_64-unknown-linux-gnu" %s | FileCheck %s --check-prefixes=X64,ALL
// RUN: fir-opt --split-input-file --target-rewrite="target=x86_64-apple-darwin" %s | FileCheck %s --check-prefixes=X64,ALL
// RUN: fir-opt --split-input-file --target-rewrite="target=aarch64-unknown-linux-gnu" %s | FileCheck %s --check-prefixes=AARCH64,ALL
// RUN: fir-opt --split-input-file --target-rewrite="target=aarch64-apple-darwin" %s | FileCheck %s --check-prefixes=AARCH64DARWIN,ALL
// RUN: fir-opt --split-input-file --target-rewrite="target=powerpc64le-unknown-linux-gnu" %s | FileCheck %s --check-prefixes=PPC,ALL
// RUN: fir-opt --split-input-file --target-rewrite="target=sparc64-unknown-linux-gnu" %s | FileCheck %s --check-prefixes=SPARCV9,ALL
// RUN: fir-opt --split-input-file --target-rewrite="target=sparcv9-sun-solaris2.11" %s | FileCheck %s --check-prefixes=SPARCV9,ALL
Expand All @@ -17,6 +19,7 @@
// I32: func.func{{.*}}@_FortranAioOutputLogical({{.*}}i1 {llvm.zeroext}) -> (i1 {llvm.zeroext})
// X64: func.func{{.*}}@_FortranAioOutputLogical({{.*}}i1 {llvm.zeroext}) -> (i1 {llvm.zeroext})
// AARCH64: func.func{{.*}}@_FortranAioOutputLogical({{.*}}i1 {llvm.zeroext}) -> (i1 {llvm.zeroext})
// AARCH64DARWIN: func.func{{.*}}@_FortranAioOutputLogical({{.*}}i1 {llvm.zeroext}) -> (i1 {llvm.zeroext})
// PPC: func.func{{.*}}@_FortranAioOutputLogical({{.*}}i1 {llvm.zeroext}) -> (i1 {llvm.zeroext})
// SPARCV9: func.func{{.*}}@_FortranAioOutputLogical({{.*}}i1 {llvm.zeroext}) -> (i1 {llvm.zeroext})
// LOONGARCH64: func.func{{.*}}@_FortranAioOutputLogical({{.*}}i1 {llvm.zeroext}) -> (i1 {llvm.zeroext})
Expand Down Expand Up @@ -49,6 +52,7 @@ func.func private @_FortranAioEndIoStatement(!fir.ref<i8>) -> i32 attributes {fi
// I32: func.func{{.*}}@_SomeFunc_si1(si1 {llvm.signext}) -> (si1 {llvm.signext})
// X64: func.func{{.*}}@_SomeFunc_si1(si1 {llvm.signext}) -> (si1 {llvm.signext})
// AARCH64: func.func{{.*}}@_SomeFunc_si1(si1 {llvm.signext}) -> (si1 {llvm.signext})
// AARCH64DARWIN: func.func{{.*}}@_SomeFunc_si1(si1 {llvm.signext}) -> (si1 {llvm.signext})
// PPC: func.func{{.*}}@_SomeFunc_si1(si1 {llvm.signext}) -> (si1 {llvm.signext})
// SPARCV9: func.func{{.*}}@_SomeFunc_si1(si1 {llvm.signext}) -> (si1 {llvm.signext})
// LOONGARCH64: func.func{{.*}}@_SomeFunc_si1(si1 {llvm.signext}) -> (si1 {llvm.signext})
Expand All @@ -69,6 +73,7 @@ func.func private @_SomeFunc_si1(si1) -> si1 attributes {fir.runtime}
// I32: func.func{{.*}}@_SomeFunc_ui1(ui1 {llvm.zeroext}) -> (ui1 {llvm.zeroext})
// X64: func.func{{.*}}@_SomeFunc_ui1(ui1 {llvm.zeroext}) -> (ui1 {llvm.zeroext})
// AARCH64: func.func{{.*}}@_SomeFunc_ui1(ui1 {llvm.zeroext}) -> (ui1 {llvm.zeroext})
// AARCH64DARWIN: func.func{{.*}}@_SomeFunc_ui1(ui1 {llvm.zeroext}) -> (ui1 {llvm.zeroext})
// PPC: func.func{{.*}}@_SomeFunc_ui1(ui1 {llvm.zeroext}) -> (ui1 {llvm.zeroext})
// SPARCV9: func.func{{.*}}@_SomeFunc_ui1(ui1 {llvm.zeroext}) -> (ui1 {llvm.zeroext})
// LOONGARCH64: func.func{{.*}}@_SomeFunc_ui1(ui1 {llvm.zeroext}) -> (ui1 {llvm.zeroext})
Expand Down Expand Up @@ -99,8 +104,20 @@ func.func private @_SomeFunc_ui1(ui1) -> ui1 attributes {fir.runtime}
// end subroutine test

// ALL-LABEL: @_QPtest_bindc
// ALL: func.func private @cfun8(i8 {llvm.signext}) -> (i8 {llvm.signext}) attributes {fir.bindc_name = "cfun8"}
// ALL: func.func private @cfun16(i16 {llvm.signext}) -> (i16 {llvm.signext}) attributes {fir.bindc_name = "cfun16"}
// I32: func.func private @cfun8(i8 {llvm.signext}) -> (i8 {llvm.signext}) attributes {fir.bindc_name = "cfun8"}
// I32: func.func private @cfun16(i16 {llvm.signext}) -> (i16 {llvm.signext}) attributes {fir.bindc_name = "cfun16"}
// X64: func.func private @cfun8(i8 {llvm.signext}) -> (i8 {llvm.signext}) attributes {fir.bindc_name = "cfun8"}
// X64: func.func private @cfun16(i16 {llvm.signext}) -> (i16 {llvm.signext}) attributes {fir.bindc_name = "cfun16"}
// AARCH64: func.func private @cfun8(i8) -> i8 attributes {fir.bindc_name = "cfun8"}
// AARCH64: func.func private @cfun16(i16) -> i16 attributes {fir.bindc_name = "cfun16"}
// AARCH64DARWIN: func.func private @cfun8(i8 {llvm.signext}) -> (i8 {llvm.signext}) attributes {fir.bindc_name = "cfun8"}
// AARCH64DARWIN: func.func private @cfun16(i16 {llvm.signext}) -> (i16 {llvm.signext}) attributes {fir.bindc_name = "cfun16"}
// PPC: func.func private @cfun8(i8 {llvm.signext}) -> (i8 {llvm.signext}) attributes {fir.bindc_name = "cfun8"}
// PPC: func.func private @cfun16(i16 {llvm.signext}) -> (i16 {llvm.signext}) attributes {fir.bindc_name = "cfun16"}
// SPARCV9: func.func private @cfun8(i8 {llvm.signext}) -> (i8 {llvm.signext}) attributes {fir.bindc_name = "cfun8"}
// SPARCV9: func.func private @cfun16(i16 {llvm.signext}) -> (i16 {llvm.signext}) attributes {fir.bindc_name = "cfun16"}
// LOONGARCH64: func.func private @cfun8(i8 {llvm.signext}) -> (i8 {llvm.signext}) attributes {fir.bindc_name = "cfun8"}
// LOONGARCH64: func.func private @cfun16(i16 {llvm.signext}) -> (i16 {llvm.signext}) attributes {fir.bindc_name = "cfun16"}
func.func @_QPtest_bindc(%arg0: !fir.ref<i8> {fir.bindc_name = "x"}, %arg1: !fir.ref<i16> {fir.bindc_name = "y"}) {
%0 = fir.load %arg0 : !fir.ref<i8>
%1 = fir.call @cfun8(%0) fastmath<contract> : (i8) -> i8
Expand Down
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