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[ELF] Improve --export-dynamic-symbol performance by checking whether wildcard is really used 

A hasWildcard pattern iterates over symVector, which can be slow when there
are many --export-dynamic-symbol. In optimistic cases, most patterns don't use
a wildcard character. hasWildcard: false can avoid a symbol table iteration.

While here, add two tests using `[` and `?`, respectively.
This commit is contained in:
Fangrui Song 2020-06-17 17:11:38 -07:00
parent 7ee758d691
commit 49279ca160
4 changed files with 11 additions and 4 deletions
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3
lld/ELF/Driver.cpp
View File

@ -1188,7 +1188,8 @@ static void readConfigs(opt::InputArgList &args) {
// -Bsymbolic-functions (if STT_FUNC), --dynamic-list. // -Bsymbolic-functions (if STT_FUNC), --dynamic-list.
for (auto *arg : args.filtered(OPT_export_dynamic_symbol)) for (auto *arg : args.filtered(OPT_export_dynamic_symbol))
config->dynamicList.push_back( config->dynamicList.push_back(
{arg->getValue(), /*isExternCpp=*/false, /*hasWildcard=*/true}); {arg->getValue(), /*isExternCpp=*/false,
/*hasWildcard=*/hasWildcard(arg->getValue())});
for (auto *arg : args.filtered(OPT_version_script)) for (auto *arg : args.filtered(OPT_version_script))
if (Optional<std::string> path = searchScript(arg->getValue())) { if (Optional<std::string> path = searchScript(arg->getValue())) {

2
lld/ELF/ScriptParser.cpp
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@ -1474,7 +1474,7 @@ void ScriptParser::readVersionDeclaration(StringRef verStr) {
expect(";"); expect(";");
} }
static bool hasWildcard(StringRef s) { bool elf::hasWildcard(StringRef s) {
return s.find_first_of("?*[") != StringRef::npos; return s.find_first_of("?*[") != StringRef::npos;
} }

2
lld/ELF/ScriptParser.h
View File

@ -27,6 +27,8 @@ void readDynamicList(MemoryBufferRef mb);
// Parses the defsym expression. // Parses the defsym expression.
void readDefsym(StringRef name, MemoryBufferRef mb); void readDefsym(StringRef name, MemoryBufferRef mb);
bool hasWildcard(StringRef s);
} // namespace elf } // namespace elf
} // namespace lld } // namespace lld

8
lld/test/ELF/export-dynamic-symbol.s
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@ -41,8 +41,12 @@
# RUN: llvm-objdump -d %t.preempt3 | FileCheck --check-prefix=PLT %s # RUN: llvm-objdump -d %t.preempt3 | FileCheck --check-prefix=PLT %s
## The option value is a glob. ## The option value is a glob.
# RUN: ld.lld -shared -Bsymbolic --export-dynamic-symbol 'f*' %t.o -o %t.preempt4 # RUN: ld.lld -shared -Bsymbolic --export-dynamic-symbol 'f*' %t.o -o - | \
# RUN: llvm-objdump -d %t.preempt4 | FileCheck --check-prefix=PLT %s # RUN: llvm-objdump -d - | FileCheck --check-prefix=PLT %s
# RUN: ld.lld -shared -Bsymbolic --export-dynamic-symbol '[f]o[o]' %t.o -o - | \
# RUN: llvm-objdump -d - | FileCheck --check-prefix=PLT %s
# RUN: ld.lld -shared -Bsymbolic --export-dynamic-symbol 'f?o' %t.o -o - | \
# RUN: llvm-objdump -d - | FileCheck --check-prefix=PLT %s
# PLT: <foo@plt> # PLT: <foo@plt>
# NOPLT-NOT: <foo@plt> # NOPLT-NOT: <foo@plt>