[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

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

test/MC/AArch64/jump-table.s

2

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

[mstorsjo]

lib/Target/AArch64/MCTargetDesc/AArch64MCAsmInfo.cpp

108

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

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

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

test/MC/AArch64/jump-table.s

2

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.

lib/Target/AArch64/MCTargetDesc/AArch64MCAsmInfo.cpp

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

test/MC/AArch64/jump-table.s

 // RUN: llvm-mc < %s -triple=aarch64-none-linux-gnu -filetype=obj | llvm-readobj -r | FileCheck %s
+// RUN: llvm-mc < %s -triple=aarch64-windows-gnu
 
   .file "<stdin>"
   .text
   .globl  test_jumptable
-  .type test_jumptable,@function
 test_jumptable:                         // @test_jumptable
   .cfi_startproc
 // BB#0:
   ubfx  w1, w0, #0, #32
   cmp w0, #4
   b.hi .LBB0_3
 // BB#1:
   adrp  x0, .LJTI0_0
.LBB0_4:                                // %lbl2
   ret
 .LBB0_5:                                // %lbl3
   movz  x0, #4
   ret
 .LBB0_6:                                // %lbl4
   movz  x0, #8
   ret
 .Ltmp0:
-  .size test_jumptable, .Ltmp0-test_jumptable
   .cfi_endproc
-  .section  .rodata,"a",@progbits
+  .section  .rodata
   .align  3
 .LJTI0_0:
   .xword  .LBB0_2
   .xword  .LBB0_4
   .xword  .LBB0_5
   .xword  .LBB0_3
   .xword  .LBB0_6