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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.

Details

Reviewers
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

Repository
rL LLVM

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 ↗(On Diff #65107)

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

PathSize
lld/
trunk/
ELF/
3 lines
test/
ELF/
11 lines

Diff 65258

lld/trunk/ELF/LinkerScript.cpp

Show First 20 Lines • Show All 526 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 || 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);
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;
} }
} }
▲ Show 20 Lines • Show All 426 Lines • Show Last 20 Lines

lld/trunk/test/ELF/linkerscript-undef.s

# 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