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Differential D56060

ELF: BLOCK Keyword linker script support
AbandonedPublic

Authored by martell on Dec 23 2018, 8:48 AM.

Details

Reviewers
ruiu
• espindola
grimar
Summary

When Linking ppc64 with lld

ld.lld: error: ./arch/powerpc/kernel/vmlinux.lds:73: unknown section directive: 0

/*

  • BLOCK(0) overrides the default output section alignment because
  • this needs to start right after .head.text in order for fixed
  • section placement to work. */

.text BLOCK(0) : AT(ADDR(.text) - LOAD_OFFSET) {

Diff Detail

Repository
rLLD LLVM Linker

Event Timeline

martell created this revision.Dec 23 2018, 8:48 AM
Herald added a reviewer: • espindola. · View Herald TranscriptDec 23 2018, 8:48 AM
Herald added subscribers: arichardson, emaste. · View Herald Transcript
martell added a comment.Dec 23 2018, 8:50 AM

I'm not sure if we should change the linker script or add BLOCK

https://github.com/ClangBuiltLinux/linux/issues/253

martell added a subscriber: nickdesaulniers.Dec 23 2018, 8:51 AM
grimar added a subscriber: grimar.Dec 24 2018, 1:58 AM

In according to the documentation, BLOCK is a synonym for ALIGN for compatibility with the older linker scripts. Given that its name sounds meaningless/confusing,
I would prefer to see the ALIGN in the scripts. Hence I suggest not to add this to LLD but fix the script. How does it sound?

grimar added a reviewer: grimar.Dec 24 2018, 1:58 AM
grimar added a comment.Jan 15 2019, 12:57 AM

Given the following external comment, can this be closed?
https://github.com/ClangBuiltLinux/linux/issues/253#issuecomment-450460750

martell abandoned this revision.Jan 24 2019, 2:43 PM

Sorry for the delay.
The change from BLOCK to ALIGN is now accepted upstream.
https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id=a652758ac1475f69d28d11b3528c4f48
Closing this and thanks @grimar

Revision Contents

PathSize
ELF/
2 lines
test/
ELF/
linkerscript/
2 lines

Diff 179449

ELF/ScriptParser.cpp

Show First 20 Lines • Show All 815 Lines • ▼ Show 20 LinesOutputSection *ScriptParser::readOutputSectionDescription(StringRef OutSec) {
if (peek() != ":") if (peek() != ":")
readSectionAddressType(Cmd); readSectionAddressType(Cmd);
expect(":"); expect(":");
std::string Location = getCurrentLocation(); std::string Location = getCurrentLocation();
if (consume("AT")) if (consume("AT"))
Cmd->LMAExpr = readParenExpr(); Cmd->LMAExpr = readParenExpr();
if (consume("ALIGN")) if (consume("ALIGN") || consume("BLOCK"))
Cmd->AlignExpr = checkAlignment(readParenExpr(), Location); Cmd->AlignExpr = checkAlignment(readParenExpr(), Location);
if (consume("SUBALIGN")) if (consume("SUBALIGN"))
Cmd->SubalignExpr = checkAlignment(readParenExpr(), Location); Cmd->SubalignExpr = checkAlignment(readParenExpr(), Location);
// Parse constraints. // Parse constraints.
if (consume("ONLY_IF_RO")) if (consume("ONLY_IF_RO"))
Cmd->Constraint = ConstraintKind::ReadOnly; Cmd->Constraint = ConstraintKind::ReadOnly;
if (consume("ONLY_IF_RW")) if (consume("ONLY_IF_RW"))
▲ Show 20 Lines • Show All 721 Lines • Show Last 20 Lines

test/ELF/linkerscript/align-r.test

Show All 11 Lines
# CHECK-NEXT: .aaa PROGBITS 0000000000000000 000040 000008 00 A 0 0 1 # CHECK-NEXT: .aaa PROGBITS 0000000000000000 000040 000008 00 A 0 0 1
# CHECK-NEXT: .bbb PROGBITS 0000000000000000 001000 000008 00 A 0 0 4096 # CHECK-NEXT: .bbb PROGBITS 0000000000000000 001000 000008 00 A 0 0 4096
# CHECK-NEXT: .ccc PROGBITS 0000000000000000 004000 000008 00 A 0 0 16384 # CHECK-NEXT: .ccc PROGBITS 0000000000000000 004000 000008 00 A 0 0 16384
SECTIONS { SECTIONS {
. = 0x10000; . = 0x10000;
.aaa : { *(.aaa) } .aaa : { *(.aaa) }
.bbb : ALIGN(4096) { *(.bbb) } .bbb : ALIGN(4096) { *(.bbb) }
.ccc : ALIGN(4096 * 4) { *(.ccc) } .ccc : BLOCK(4096 * 4) { *(.ccc) }
}}