From 60ff4dd9cd8a5052067b2dee1fc68bfba1f695cc Mon Sep 17 00:00:00 2001 From: Fangrui Song Date: Thu, 12 Sep 2019 08:55:17 +0000 Subject: [PATCH] [ELF] Support -z undefs -z undefs is the inverse of -z defs. It allows unresolved references from object files. This can be used to cancel --no-undefined or -z defs. Reviewed By: ruiu Differential Revision: https://reviews.llvm.org/D67479 llvm-svn: 371715 --- lld/ELF/Driver.cpp | 4 +++- lld/test/ELF/zdefs.s | 6 ++++++ 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp index 9cab10e49da4..5022c81df780 100644 --- a/lld/ELF/Driver.cpp +++ b/lld/ELF/Driver.cpp @@ -386,7 +386,7 @@ static bool isKnownZFlag(StringRef s) { s == "noexecstack" || s == "nokeep-text-section-prefix" || s == "norelro" || s == "noseparate-code" || s == "notext" || s == "now" || s == "origin" || s == "relro" || s == "retpolineplt" || - s == "rodynamic" || s == "text" || s == "wxneeded" || + s == "rodynamic" || s == "text" || s == "undefs" || s == "wxneeded" || s.startswith("common-page-size") || s.startswith("max-page-size=") || s.startswith("stack-size="); } @@ -517,6 +517,8 @@ static UnresolvedPolicy getUnresolvedSymbolPolicy(opt::InputArgList &args) { case OPT_z: if (StringRef(arg->getValue()) == "defs") return errorOrWarn; + if (StringRef(arg->getValue()) == "undefs") + return UnresolvedPolicy::Ignore; continue; } } diff --git a/lld/test/ELF/zdefs.s b/lld/test/ELF/zdefs.s index 21bec77b3bfb..def217f6c0e1 100644 --- a/lld/test/ELF/zdefs.s +++ b/lld/test/ELF/zdefs.s @@ -1,9 +1,15 @@ # REQUIRES: x86 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o + +## Unresolved references from object files are allowed by default for -shared. # RUN: ld.lld -shared %t.o -o %t1.so +## -z defs disallows unresolved references. # RUN: not ld.lld -z defs -shared %t.o -o %t1.so 2>&1 | FileCheck -check-prefix=ERR %s # ERR: error: undefined symbol: foo # ERR: >>> referenced by {{.*}}:(.text+0x1) +## -z undefs allows unresolved references. +# RUN: ld.lld -z defs -z undefs -shared %t.o -o /dev/null 2>&1 | count 0 + callq foo@PLT