commit 84f3a4c19a17256a66e00ea94232b2004c3eeaf8
author David Spickett <david.spickett@linaro.org> Tue Feb 13 10:38:38 2024 +0000
committer Copybara-Service <copybara-worker@google.com> Tue Feb 13 02:45:15 2024 -0800
tree fc4cc6a60966ce9101fed19476c2f5cf86914e05
parent 0902ffab88b2bf8b4b642eac4f35cc080c8481f4

[flang][Driver] Add -masm option to flang (#81490)

The motivation here was a suggestion over in Compiler Explorer. You can
use `-mllvm` already to do this but since gfortran supports `-masm`, I
figured I'd try to add it.

This is done by flang expanding `-masm` into `-mllvm x86-asm-syntax=`,
then passing that to fc1. Which then collects all the `-mllvm` options
and forwards them on.

The code to expand it comes from clang `Clang::AddX86TargetArgs` (there
are some other places doing the same thing too). However I've removed
the `-inline-asm` that clang adds, as fortran doesn't have inline
assembly.

So `-masm` for flang purely changes the style of assembly output.

```
$ ./bin/flang-new /tmp/test.f90 -o - -S -target x86_64-linux-gnu
<...>
        pushq   %rbp
$ ./bin/flang-new /tmp/test.f90 -o - -S -target x86_64-linux-gnu -masm=att
<...>
        pushq   %rbp
$ ./bin/flang-new /tmp/test.f90 -o - -S -target x86_64-linux-gnu -masm=intel
<...>
        push    rbp
```

The test is adapted from `clang/test/Driver/masm.c` by removing the
clang-cl related lines and changing the 32 bit triples to 64 bit triples
since flang doesn't support 32 bit targets.

GitOrigin-RevId: 9ca1a1575a337931d0e49859f83a0d5b70916abd

test/Driver/masm.f90

diff --git a/test/Driver/masm.f90 b/test/Driver/masm.f90
new file mode 100644
index 0000000..c5c44ef
--- /dev/null
+++ b/test/Driver/masm.f90
@@ -0,0 +1,10 @@
+! RUN: %flang --target=x86_64-unknown-linux -masm=intel -S %s -### 2>&1 | FileCheck --check-prefix=CHECK-INTEL %s
+! RUN: %flang --target=x86_64-unknown-linux -masm=att -S %s -### 2>&1 | FileCheck --check-prefix=CHECK-ATT %s
+! RUN: not %flang --target=x86_64-unknown-linux -S -masm=somerequired %s -### 2>&1 | FileCheck --check-prefix=CHECK-SOMEREQUIRED %s
+! RUN: %flang --target=aarch64-unknown-eabi -S -masm=intel %s -### 2>&1 | FileCheck --check-prefix=CHECK-AARCH64 %s
+
+! CHECK-INTEL: "-mllvm" "-x86-asm-syntax=intel"
+! CHECK-ATT: "-mllvm" "-x86-asm-syntax=att"
+! CHECK-SOMEREQUIRED: error: unsupported argument 'somerequired' to option '-masm='
+! CHECK-AARCH64: warning: argument unused during compilation: '-masm=intel'
+! CHECK-AARCH64-NOT: -x86-asm-syntax=intel