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Differential D125980

[AArch64] Fix the generation of BE Nops
ClosedPublic

Authored by dmgreen on May 19 2022, 8:16 AM.

Details

Reviewers
t.p.northover
efriedma
john.brawn
amilendra
NickGuy
Commits
rG1379b150991f: [AArch64] Fix the generation of BE Nops
Summary

Big endian Nops were being generated as d5 03 20 1f fnmadd s21, s30, s0, s0, getting the bytes of the NOP in the wrong order. This switches the bytes to not be dependant on the endianness.

Diff Detail

Event Timeline

dmgreen created this revision.May 19 2022, 8:16 AM
Herald added a project: Restricted Project. · View Herald TranscriptMay 19 2022, 8:16 AM
Herald added subscribers: hiraditya, kristof.beyls. · View Herald Transcript
dmgreen requested review of this revision.May 19 2022, 8:16 AM
Herald added a project: Restricted Project. · View Herald TranscriptMay 19 2022, 8:16 AM
john.brawn accepted this revision.May 19 2022, 9:08 AM

LGTM.

This revision is now accepted and ready to land.May 19 2022, 9:08 AM
Harbormaster completed remote builds in B165336: Diff 430685.May 19 2022, 9:32 AM
This revision was landed with ongoing or failed builds.May 20 2022, 1:31 AM
Closed by commit rG1379b150991f: [AArch64] Fix the generation of BE Nops (authored by dmgreen). · Explain Why
This revision was automatically updated to reflect the committed changes.
dmgreen added a commit: rG1379b150991f: [AArch64] Fix the generation of BE Nops.

Revision Contents

PathSize
llvm/
lib/
Target/
AArch64/
MCTargetDesc/
2 lines
test/
MC/
AArch64/
14 lines

Diff 430902

llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp

Show First 20 Lines • Show All 465 Lines • ▼ Show 20 Linesbool AArch64AsmBackend::writeNopData(raw_ostream &OS, uint64_t Count,
// If the count is not 4-byte aligned, we must be writing data into the text // If the count is not 4-byte aligned, we must be writing data into the text
// section (otherwise we have unaligned instructions, and thus have far // section (otherwise we have unaligned instructions, and thus have far
// bigger problems), so just write zeros instead. // bigger problems), so just write zeros instead.
OS.write_zeros(Count % 4); OS.write_zeros(Count % 4);
// We are properly aligned, so write NOPs as requested. // We are properly aligned, so write NOPs as requested.
Count /= 4; Count /= 4;
for (uint64_t i = 0; i != Count; ++i) for (uint64_t i = 0; i != Count; ++i)
support::endian::write<uint32_t>(OS, 0xd503201f, Endian); OS.write("\x1f\x20\x03\xd5", 4);
return true; return true;
} }
bool AArch64AsmBackend::shouldForceRelocation(const MCAssembler &Asm, bool AArch64AsmBackend::shouldForceRelocation(const MCAssembler &Asm,
const MCFixup &Fixup, const MCFixup &Fixup,
const MCValue &Target) { const MCValue &Target) {
unsigned Kind = Fixup.getKind(); unsigned Kind = Fixup.getKind();
if (Kind >= FirstLiteralRelocationKind) if (Kind >= FirstLiteralRelocationKind)
▲ Show 20 Lines • Show All 303 Lines • Show Last 20 Lines

llvm/test/MC/AArch64/align.s

  • This file was added.
// RUN: llvm-mc -filetype=obj -triple aarch64-none-eabi %s | llvm-objdump -d - | FileCheck %s
// RUN: llvm-mc -filetype=obj -triple aarch64_be-none-eabi %s | llvm-objdump -d - | FileCheck %s
// CHECK: 0: 00 00 80 d2 mov x0, #0
// CHECK: 4: 00 00 80 d2 mov x0, #0
// CHECK: 8: 1f 20 03 d5 nop
// CHECK: c: 1f 20 03 d5 nop
// CHECK: 10: 00 00 80 d2 mov x0, #0
.text
mov x0, #0
mov x0, #0
.p2align 4
mov x0, #0