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Differential D22664

[ELF/Linkerscript] Define an absolute if we find an undefined during symbol assignment
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Authored by davide on Jul 21 2016, 10:25 PM.

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ruiu
Commits
rG8ab4108df201: [ELF/Linkerscript] Define an absolute if we find an undefined.
rLLD276536: [ELF/Linkerscript] Define an absolute if we find an undefined.
rL276536: [ELF/Linkerscript] Define an absolute if we find an undefined.
Summary

Avoid an undefined reference failure.

Diff Detail

Event Timeline

davide updated this revision to Diff 65027.Jul 21 2016, 10:25 PM
davide retitled this revision from to [ELF/Linkerscript] Define an absolute if we find an undefined during symbol assignment.
davide updated this object.
davide added a reviewer: ruiu.
davide added a subscriber: llvm-commits.
grimar added a subscriber: grimar.Jul 22 2016, 1:54 AM
evgeny777 added a subscriber: evgeny777.Jul 22 2016, 2:25 AM
emaste added a subscriber: emaste.Jul 22 2016, 6:07 AM
emaste added a comment.Jul 22 2016, 6:16 AM

Conflicts with recently committed rL276398

davide updated this revision to Diff 65107.Jul 22 2016, 11:16 AM
ruiu accepted this revision.Jul 23 2016, 4:04 AM
ruiu edited edge metadata.

LGTM

ELF/LinkerScript.cpp
536–539

I think we usually write !B instead of B == nullptr.

This revision is now accepted and ready to land.Jul 23 2016, 4:04 AM
Closed by commit rL276536: [ELF/Linkerscript] Define an absolute if we find an undefined. (authored by davide). · Explain WhyJul 23 2016, 3:16 PM
This revision was automatically updated to reflect the committed changes.

Revision Contents

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ELF/
3 lines
test/
ELF/
11 lines

Diff 65107

ELF/LinkerScript.cpp

Show First 20 Lines • Show All 492 Lines • ▼ Show 20 Lines
} }
template <class ELFT> void LinkerScript<ELFT>::addScriptedSymbols() { template <class ELFT> void LinkerScript<ELFT>::addScriptedSymbols() {
for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands) { for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands) {
auto *Cmd = dyn_cast<SymbolAssignment>(Base.get()); auto *Cmd = dyn_cast<SymbolAssignment>(Base.get());
if (!Cmd || Cmd->Name == ".") if (!Cmd || Cmd->Name == ".")
continue; continue;
if (Symtab<ELFT>::X->find(Cmd->Name) == nullptr) SymbolBody *B = Symtab<ELFT>::X->find(Cmd->Name);
if (B == nullptr || B->isUndefined())
Symtab<ELFT>::X->addAbsolute(Cmd->Name, Symtab<ELFT>::X->addAbsolute(Cmd->Name,
Cmd->Hidden ? STV_HIDDEN : STV_DEFAULT); Cmd->Hidden ? STV_HIDDEN : STV_DEFAULT);
ruiuUnsubmitted
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I think we usually write !B instead of B == nullptr.

ruiu: I think we usually write `!B` instead of `B == nullptr`.
else else
// Symbol already exists in symbol table. If it is provided // Symbol already exists in symbol table. If it is provided
// then we can't override its value. // then we can't override its value.
Cmd->Ignore = Cmd->Provide; Cmd->Ignore = Cmd->Provide;
} }
} }
template <class ELFT> bool LinkerScript<ELFT>::hasPhdrsCommands() { template <class ELFT> bool LinkerScript<ELFT>::hasPhdrsCommands() {
▲ Show 20 Lines • Show All 424 Lines • Show Last 20 Lines

test/ELF/linkerscript-undef.s

  • This file was added.
# REQUIRES: x86
# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
# RUN: echo "SECTIONS { patatino = 0x1234; }" > %t.script
# RUN: ld.lld -o %t1 --script %t.script %t
# RUN: llvm-objdump -t %t1 | FileCheck %s
# CHECK: 0000000000001234 *ABS* 00000000 patatino
.global _start
_start:
call patatino