[AArch64, COFF] Interpret .align as power of two for COFF as well

[mstorsjo]

Summary

Remove some unrelated directives that can't be assembled for COFF from the existing jump table test and rerun that test for windows as well.

[efriedma]

lib/Target/AArch64/MCTargetDesc/AArch64MCAsmInfo.cpp

108 ↗

(On Diff #107056)

Is there any particular reason to choose one way or the other here?

test/MC/AArch64/jump-table.s

2 ↗

(On Diff #107056)

This is just checking whether llvm-mc crashes; is that intentional?

[mstorsjo]

lib/Target/AArch64/MCTargetDesc/AArch64MCAsmInfo.cpp

108 ↗

(On Diff #107056)

In my case, it is to make it possible to assemble existing handwritten aarch64 gas assembly (that currently targets linux and darwin) for windows as well. For armv7, we already have the same situation where linux/darwin gas assembly also can be built for windows, but only while using the armv7-windows-gnu target, not the armv7-windows-msvc target.

If you'd prefer that, I could try to make that distinction here as well, and only match the gas behaviour in the -gnu variant.

test/MC/AArch64/jump-table.s

2 ↗

(On Diff #107056)

It's intentional in the sense that I wanted to test that .align 3 is interpreted as 8 byte alignment; prior to the code change this fails to assemble since 3 bytes isn't a valid alignment.

[efriedma]

lib/Target/AArch64/MCTargetDesc/AArch64MCAsmInfo.cpp

108 ↗

(On Diff #107056)

Should be fine as-is, I think; ARMCOFFMCAsmInfoMicrosoft also sets AlignmentIsInBytes to false.

test/MC/AArch64/jump-table.s

2 ↗

(On Diff #107056)

I'd prefer a test that actually verifies that the .align directive produces the correct object file.

[mstorsjo]

Updated to a completely new test that explicitly checks the alignment.

[efriedma]

test/MC/COFF/aarch64-align.s

1 ↗

(On Diff #107165)

Test needs to be in a directory which allows AArch64 tests (probably test/MC/AArch64/). lit.local.cfg for test/MC/COFF/ requires the x86 backend.

[mstorsjo]

Moved the test to the MC/AArch64 directory.

[efriedma]

LGTM.

llvm/trunk/lib/Target/AArch64/MCTargetDesc/AArch64MCAsmInfo.cpp

AArch64MCAsmInfoELF::AArch64MCAsmInfoELF(const Triple &T) {
 
   HasIdentDirective = true;
 }
 
 AArch64MCAsmInfoCOFF::AArch64MCAsmInfoCOFF() {
   CommentString = ";";
   PrivateGlobalPrefix = ".L";
   PrivateLabelPrefix = ".L";
+  AlignmentIsInBytes = false;
 }

llvm/trunk/test/MC/AArch64/coff-align.s

+// RUN: llvm-mc -filetype=obj -triple aarch64-windows-gnu %s | llvm-readobj -s -sd | FileCheck %s
+    .text
+    .align 5
+f0:
+    ret
+
+// CHECK: IMAGE_SCN_ALIGN_32BYTES