[ELF] - Resolve references properly when using .symver directive
This is PR28414.
Previously LLD was unable to link following:
(failed with undefined symbol bar)
Version script:
SOME_VERSION { global: *; };
.global _start
.global bar
.symver _start, bar@@SOME_VERSION
_start:
jmp bar
Manual has next description:
.symver name, name2@@nodename
In this case, the symbol name must exist and be defined within the file being assembled. It is similar to name2@nodename.
The difference is name2@@nodename will also be used to resolve references to name2 by the linker
https://sourceware.org/binutils/docs/as/Symver.html
Patch implements that. If we have name@@ver symbol and name is undefined, name@@ver is used to resolve references to name.
If name is defined then multiple definition error is emited, that is consistent with what bfd do.
Differential revision: https://reviews.llvm.org/D33680
llvm-svn: 307077
diff --git a/lld/ELF/Symbols.cpp b/lld/ELF/Symbols.cpp
index e8cd662..148acfb 100644
--- a/lld/ELF/Symbols.cpp
+++ b/lld/ELF/Symbols.cpp
@@ -272,7 +272,12 @@
}
// It is an error if the specified version is not defined.
- error(toString(File) + ": symbol " + S + " has undefined version " + Verstr);
+ // Usually version script is not provided when linking executable,
+ // but we may still want to override a versioned symbol from DSO,
+ // so we do not report error in this case.
+ if (Config->Shared)
+ error(toString(File) + ": symbol " + S + " has undefined version " +
+ Verstr);
}
Defined::Defined(Kind K, StringRefZ Name, bool IsLocal, uint8_t StOther,
