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[ELF] Simplify resolveDefined and resolveCommon

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This is NFC for valid input (COMMON symbols cannot be weak or versioned).
This commit is contained in:
Fangrui Song
2022-02-24 14:08:06 -08:00
parent aeec9671fb
commit 6d94340809
2 changed files with 39 additions and 59 deletions
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96
lld/ELF/Symbols.cpp
View File

@@ -529,48 +529,27 @@ void Symbol::resolveUndefined(const Undefined &other) {
// Compare two symbols. Return 1 if the new symbol should win, -1 if
// the new symbol should lose, or 0 if there is a conflict.
int Symbol::compare(const Symbol *other) const {
assert(other->isDefined() || other->isCommon());
if (!isDefined() && !isCommon())
return 1;
bool Symbol::compare(const Defined &other) const {
if (LLVM_UNLIKELY(isCommon())) {
if (config->warnCommon)
warn("common " + getName() + " is overridden");
return !other.isWeak();
}
if (!isDefined())
return true;
// .symver foo,foo@@VER unfortunately creates two defined symbols: foo and
// foo@@VER. In GNU ld, if foo and foo@@VER are in the same file, foo is
// ignored. In our implementation, when this is foo, this->getName() may still
// contain @@, return 1 in this case as well.
if (file == other->file) {
if (other->getName().contains("@@"))
return 1;
// contain @@, return true in this case as well.
if (LLVM_UNLIKELY(file == other.file)) {
if (other.getName().contains("@@"))
return true;
if (getName().contains("@@"))
return -1;
return false;
}
if (other->isWeak())
return -1;
if (isWeak())
return 1;
if (isCommon() && other->isCommon()) {
if (config->warnCommon)
warn("multiple common of " + getName());
return 0;
}
if (isCommon()) {
if (config->warnCommon)
warn("common " + getName() + " is overridden");
return 1;
}
if (other->isCommon()) {
if (config->warnCommon)
warn("common " + getName() + " is overridden");
return -1;
}
return 0;
return isWeak() && !other.isWeak();
}
void elf::reportDuplicate(const Symbol &sym, InputFile *newFile,
@@ -608,45 +587,46 @@ void elf::reportDuplicate(const Symbol &sym, InputFile *newFile,
}
void Symbol::checkDuplicate(const Defined &other) const {
if (compare(&other) == 0)
if (isDefined() && !isWeak() && !other.isWeak())
reportDuplicate(*this, other.file,
dyn_cast_or_null<InputSectionBase>(other.section),
other.value);
}
void Symbol::resolveCommon(const CommonSymbol &other) {
int cmp = compare(&other);
if (cmp < 0)
if (isDefined() && !isWeak()) {
if (config->warnCommon)
warn("common " + getName() + " is overridden");
return;
}
if (cmp > 0) {
if (auto *s = dyn_cast<SharedSymbol>(this)) {
// Increase st_size if the shared symbol has a larger st_size. The shared
// symbol may be created from common symbols. The fact that some object
// files were linked into a shared object first should not change the
// regular rule that picks the largest st_size.
uint64_t size = s->size;
replace(other);
if (size > cast<CommonSymbol>(this)->size)
cast<CommonSymbol>(this)->size = size;
} else {
replace(other);
if (CommonSymbol *oldSym = dyn_cast<CommonSymbol>(this)) {
if (config->warnCommon)
warn("multiple common of " + getName());
oldSym->alignment = std::max(oldSym->alignment, other.alignment);
if (oldSym->size < other.size) {
oldSym->file = other.file;
oldSym->size = other.size;
}
return;
}
CommonSymbol *oldSym = cast<CommonSymbol>(this);
oldSym->alignment = std::max(oldSym->alignment, other.alignment);
if (oldSym->size < other.size) {
oldSym->file = other.file;
oldSym->size = other.size;
if (auto *s = dyn_cast<SharedSymbol>(this)) {
// Increase st_size if the shared symbol has a larger st_size. The shared
// symbol may be created from common symbols. The fact that some object
// files were linked into a shared object first should not change the
// regular rule that picks the largest st_size.
uint64_t size = s->size;
replace(other);
if (size > cast<CommonSymbol>(this)->size)
cast<CommonSymbol>(this)->size = size;
} else {
replace(other);
}
}
void Symbol::resolveDefined(const Defined &other) {
int cmp = compare(&other);
if (cmp > 0)
if (compare(other))
replace(other);
}

2
lld/ELF/Symbols.h
View File

@@ -228,7 +228,7 @@ private:
void resolveLazy(const LazyObject &other);
void resolveShared(const SharedSymbol &other);
int compare(const Symbol *other) const;
bool compare(const Defined &other) const;
inline size_t getSymbolSize() const;