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Fix assigning to _gp in linker scripts.

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The previous logic was to try to detect if a linker script defined _gp
by checking !ElfSym::MipsGp->Value. That doesn't work in all cases as
the assigned value can be 0.

We now just always defined it Writer.cpp and always overwrite it
afterwards if needed.

llvm-svn: 313788
This commit is contained in:
Rafael Espindola
2017-09-20 18:30:57 +00:00
parent 1b30d63aeb
commit 9be24cf516
3 changed files with 9 additions and 1 deletions
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1
lld/ELF/LinkerScript.cpp
View File

@@ -148,6 +148,7 @@ void LinkerScript::assignSymbol(SymbolAssignment *Cmd, bool InSec) {
ExprValue V = Cmd->Expression();
if (V.isAbsolute()) {
Sym->Value = V.getValue();
Sym->Section = nullptr;
} else {
Sym->Section = V.Sec;
Sym->Value = V.getSectionOffset();

2
lld/ELF/Writer.cpp
View File

@@ -964,7 +964,7 @@ template <class ELFT> void Writer<ELFT>::setReservedSymbolSections() {
// Setup MIPS _gp_disp/__gnu_local_gp symbols which should
// be equal to the _gp symbol's value.
if (ElfSym::MipsGp && !ElfSym::MipsGp->Value) {
if (ElfSym::MipsGp) {
// Find GP-relative section with the lowest address
// and use this address to calculate default _gp value.
for (OutputSection *OS : OutputSections) {

7
lld/test/ELF/mips-gp-ext.s
View File

@@ -10,6 +10,13 @@
# RUN: ld.lld -shared -o %t.rel.so --script %t.rel.script %t.o
# RUN: llvm-objdump -s -t %t.rel.so | FileCheck --check-prefix=REL %s
# RUN: echo "SECTIONS { \
# RUN: .text : { *(.text) } \
# RUN: _gp = 0x100 + ABSOLUTE(.); \
# RUN: .got : { *(.got) } }" > %t.rel.script
# RUN: ld.lld -shared -o %t.rel.so --script %t.rel.script %t.o
# RUN: llvm-objdump -s -t %t.rel.so | FileCheck --check-prefix=REL %s
# RUN: echo "SECTIONS { \
# RUN: .text : { *(.text) } \
# RUN: _gp = 0x200; \