[lld] r283431 - [ELF] Don't fail if undefined symbol is not used
Eugene Leviant via llvm-commits
llvm-commits at lists.llvm.org
Thu Oct 6 02:45:04 PDT 2016
Author: evgeny777
Date: Thu Oct 6 04:45:04 2016
New Revision: 283431
URL: http://llvm.org/viewvc/llvm-project?rev=283431&view=rev
Log:
[ELF] Don't fail if undefined symbol is not used
Differential revision: https://reviews.llvm.org/D25240
Added:
lld/trunk/test/ELF/Inputs/use-bar.s
Modified:
lld/trunk/ELF/Relocations.cpp
lld/trunk/ELF/Writer.cpp
lld/trunk/test/ELF/libsearch.s
lld/trunk/test/ELF/linkerscript/edata-etext.s
lld/trunk/test/ELF/sysroot.s
lld/trunk/test/ELF/undef-shared.s
lld/trunk/test/ELF/undef.s
Modified: lld/trunk/ELF/Relocations.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Relocations.cpp?rev=283431&r1=283430&r2=283431&view=diff
==============================================================================
--- lld/trunk/ELF/Relocations.cpp (original)
+++ lld/trunk/ELF/Relocations.cpp Thu Oct 6 04:45:04 2016
@@ -47,6 +47,7 @@
#include "SymbolTable.h"
#include "Target.h"
#include "Thunks.h"
+#include "Strings.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/raw_ostream.h"
@@ -519,6 +520,25 @@ static typename ELFT::uint computeAddend
return Addend;
}
+static void reportUndefined(SymbolBody &Sym) {
+ if (Config->UnresolvedSymbols == UnresolvedPolicy::Ignore)
+ return;
+
+ if (Config->Shared && Sym.symbol()->Visibility == STV_DEFAULT &&
+ Config->UnresolvedSymbols != UnresolvedPolicy::NoUndef)
+ return;
+
+ std::string Msg = "undefined symbol: ";
+ Msg += Config->Demangle ? demangle(Sym.getName()) : Sym.getName().str();
+
+ if (Sym.File)
+ Msg += " in " + getFilename(Sym.File);
+ if (Config->UnresolvedSymbols == UnresolvedPolicy::Warn)
+ warn(Msg);
+ else
+ error(Msg);
+}
+
// The reason we have to do this early scan is as follows
// * To mmap the output file, we need to know the size
// * For that, we need to know how many dynamic relocs we will have.
@@ -558,6 +578,10 @@ static void scanRelocs(InputSectionBase<
SymbolBody &Body = File.getRelocTargetSym(RI);
uint32_t Type = RI.getType(Config->Mips64EL);
+ // We only report undefined symbols if they are referenced somewhere in the code.
+ if (!Body.isLocal() && Body.isUndefined() && !Body.symbol()->isWeak())
+ reportUndefined(Body);
+
RelExpr Expr = Target->getRelExpr(Type, Body);
bool Preemptible = isPreemptible(Body, Type);
Expr = adjustExpr(File, Body, IsWrite, Expr, Type, Buf + RI.r_offset);
Modified: lld/trunk/ELF/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=283431&r1=283430&r2=283431&view=diff
==============================================================================
--- lld/trunk/ELF/Writer.cpp (original)
+++ lld/trunk/ELF/Writer.cpp Thu Oct 6 04:45:04 2016
@@ -307,25 +307,6 @@ template <class ELFT> void Writer<ELFT>:
error(EC, "failed to write to the output file");
}
-template <class ELFT> static void reportUndefined(SymbolBody *Sym) {
- if (Config->UnresolvedSymbols == UnresolvedPolicy::Ignore)
- return;
-
- if (Config->Shared && Sym->symbol()->Visibility == STV_DEFAULT &&
- Config->UnresolvedSymbols != UnresolvedPolicy::NoUndef)
- return;
-
- std::string Msg = "undefined symbol: ";
- Msg += Config->Demangle ? demangle(Sym->getName()) : Sym->getName().str();
-
- if (Sym->File)
- Msg += " in " + getFilename(Sym->File);
- if (Config->UnresolvedSymbols == UnresolvedPolicy::Warn)
- warn(Msg);
- else
- error(Msg);
-}
-
template <class ELFT>
static bool shouldKeepInSymtab(InputSectionBase<ELFT> *Sec, StringRef SymName,
const SymbolBody &B) {
@@ -819,11 +800,6 @@ template <class ELFT> void Writer<ELFT>:
for (Symbol *S : Symtab<ELFT>::X->getSymbols()) {
SymbolBody *Body = S->body();
- // We only report undefined symbols in regular objects. This means that we
- // will accept an undefined reference in bitcode if it can be optimized out.
- if (S->IsUsedInRegularObj && Body->isUndefined() && !S->isWeak())
- reportUndefined<ELFT>(Body);
-
if (!includeInSymtab<ELFT>(*Body))
continue;
if (Out<ELFT>::SymTab)
Added: lld/trunk/test/ELF/Inputs/use-bar.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/Inputs/use-bar.s?rev=283431&view=auto
==============================================================================
--- lld/trunk/test/ELF/Inputs/use-bar.s (added)
+++ lld/trunk/test/ELF/Inputs/use-bar.s Thu Oct 6 04:45:04 2016
@@ -0,0 +1,2 @@
+.section .bar,"a"
+ .quad _bar
Modified: lld/trunk/test/ELF/libsearch.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/libsearch.s?rev=283431&r1=283430&r2=283431&view=diff
==============================================================================
--- lld/trunk/test/ELF/libsearch.s (original)
+++ lld/trunk/test/ELF/libsearch.s Thu Oct 6 04:45:04 2016
@@ -3,6 +3,8 @@
// RUN: %p/Inputs/libsearch-dyn.s -o %tdyn.o
// RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux \
// RUN: %p/Inputs/libsearch-st.s -o %tst.o
+// RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux \
+// RUN: %p/Inputs/use-bar.s -o %tbar.o
// RUN: mkdir -p %t.dir
// RUN: ld.lld -shared %tdyn.o -o %t.dir/libls.so
// RUN: cp -f %t.dir/libls.so %t.dir/libls2.so
@@ -15,8 +17,10 @@
// RUN: | FileCheck --check-prefix=NOLIBRARY %s
// NOLIBRARY: missing arg value for "-l", expected 1 argument.
+// Should link normally, because _bar is not used
+// RUN: ld.lld -o %t3 %t.o
// Should not link because of undefined symbol _bar
-// RUN: not ld.lld -o %t3 %t.o 2>&1 \
+// RUN: not ld.lld -o %t3 %t.o %tbar.o 2>&1 \
// RUN: | FileCheck --check-prefix=UNDEFINED %s
// UNDEFINED: undefined symbol: _bar
Modified: lld/trunk/test/ELF/linkerscript/edata-etext.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/linkerscript/edata-etext.s?rev=283431&r1=283430&r2=283431&view=diff
==============================================================================
--- lld/trunk/test/ELF/linkerscript/edata-etext.s (original)
+++ lld/trunk/test/ELF/linkerscript/edata-etext.s Thu Oct 6 04:45:04 2016
@@ -3,8 +3,8 @@
# RUN: echo "SECTIONS { }" > %t.script
# RUN: not ld.lld %t.o -script %t.script -o %t 2>&1 | FileCheck %s
# CHECK: undefined symbol: _edata
-# CHECK: undefined symbol: _end
# CHECK: undefined symbol: _etext
+# CHECK: undefined symbol: _end
.global _start,_end,_etext,_edata
.text
Modified: lld/trunk/test/ELF/sysroot.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/sysroot.s?rev=283431&r1=283430&r2=283431&view=diff
==============================================================================
--- lld/trunk/test/ELF/sysroot.s (original)
+++ lld/trunk/test/ELF/sysroot.s Thu Oct 6 04:45:04 2016
@@ -34,3 +34,4 @@
.globl _start,_bar
_start:
+ call _bar
Modified: lld/trunk/test/ELF/undef-shared.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/undef-shared.s?rev=283431&r1=283430&r2=283431&view=diff
==============================================================================
--- lld/trunk/test/ELF/undef-shared.s (original)
+++ lld/trunk/test/ELF/undef-shared.s Thu Oct 6 04:45:04 2016
@@ -12,3 +12,8 @@
# CHECK: undefined symbol: protected in {{.*}}
.global protected
.protected protected
+
+.section .data, "a"
+ .quad hidden
+ .quad internal
+ .quad protected
Modified: lld/trunk/test/ELF/undef.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/undef.s?rev=283431&r1=283430&r2=283431&view=diff
==============================================================================
--- lld/trunk/test/ELF/undef.s (original)
+++ lld/trunk/test/ELF/undef.s Thu Oct 6 04:45:04 2016
@@ -4,9 +4,9 @@
# RUN: llvm-ar rc %t2.a %t2.o
# RUN: not ld.lld %t.o %t2.a -o %t.exe 2>&1 | FileCheck %s
# RUN: not ld.lld -pie %t.o %t2.a -o %t.exe 2>&1 | FileCheck %s
-# CHECK: undefined symbol: foo(int) in
-# CHECK: undefined symbol: bar in
# CHECK: undefined symbol: foo in
+# CHECK: undefined symbol: bar in
+# CHECK: undefined symbol: foo(int) in
# CHECK: undefined symbol: zed2 in {{.*}}2.a({{.*}}.o)
# RUN: not ld.lld %t.o %t2.a -o %t.exe -no-demangle 2>&1 | \
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