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[lld][ELF] Fix wrap when __real_X is weak to avoid undefined symbol #98297

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Merged
merged 2 commits into from
Jul 11, 2024
Merged

[lld][ELF] Fix wrap when __real_X is weak to avoid undefined symbol #98297

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6609380
[lld][ELF] Fix wrap when __real_X is weak
xdqi Jul 10, 2024
aaee953
[lld][ELF] Fix format
xdqi Jul 11, 2024
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6 changes: 5 additions & 1 deletion lld/ELF/Driver.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2551,8 +2551,12 @@ static std::vector<WrappedSymbol> addWrappedSymbols(opt::InputArgList &args) {
// If __real_ is referenced, pull in the symbol if it is lazy. Do this after
// processing __wrap_ as that may have referenced __real_.
StringRef realName = saver().save("__real_" + name);
if (symtab.find(realName))
if (Symbol *real = symtab.find(realName)) {
symtab.addUnusedUndefined(name, sym->binding);
// Update sym's binding, which will replace real's later in
// SymbolTable::wrap.
sym->binding = real->binding;
}

Symbol *real = symtab.addUnusedUndefined(realName);
v.push_back({sym, real, wrap});
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23 changes: 23 additions & 0 deletions lld/test/ELF/wrap-weak.s
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@@ -0,0 +1,23 @@
# REQUIRES: x86
# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o
# RUN: ld.lld -shared -o %t.so %t.o -wrap foo

# RUN: llvm-readelf --dyn-syms %t.so | FileCheck %s

# CHECK: Symbol table '.dynsym' contains 4 entries:
# CHECK: NOTYPE LOCAL DEFAULT UND
# CHECK-NEXT: NOTYPE WEAK DEFAULT UND foo
# CHECK-NEXT: NOTYPE GLOBAL DEFAULT [[#]] __wrap_foo
# CHECK-NEXT: NOTYPE GLOBAL DEFAULT [[#]] _start

.global foo
.weak __real_foo

.global __wrap_foo
__wrap_foo:
movq __real_foo@gotpcrel(%rip), %rax
call __real_foo@plt

.global _start
_start:
call foo@plt
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