diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -2196,16 +2196,19 @@
real->scriptDefined = true;
sym->scriptDefined = true;
- // Tell LTO not to eliminate these symbols.
- sym->isUsedInRegularObj = true;
- // If sym is referenced in any object file, bitcode file or shared object,
- // retain wrap which is the redirection target of sym. If the object file
- // defining sym has sym references, we cannot easily distinguish the case
- // from cases where sym is not referenced. Retain wrap because we choose to
- // wrap sym references regardless of whether sym is defined
+ // If a symbol is referenced in any object file, bitcode file or shared
+ // object, mark its redirection target (foo for __real_foo and __wrap_foo
+ // for foo) as referenced after redirection, which will be used to tell LTO
+ // to not eliminate the redirection target. If the object file defining the
+ // symbol also references it, we cannot easily distinguish the case from
+ // cases where the symbol is not referenced. Retain the redirection target
+ // in this case because we choose to wrap symbol references regardless of
+ // whether the symbol is defined
// (https://sourceware.org/bugzilla/show_bug.cgi?id=26358).
+ if (real->referenced || real->isDefined())
+ sym->referencedAfterWrapping = true;
if (sym->referenced || sym->isDefined())
- wrap->isUsedInRegularObj = true;
+ wrap->referencedAfterWrapping = true;
}
return v;
}
diff --git a/lld/ELF/LTO.cpp b/lld/ELF/LTO.cpp
--- a/lld/ELF/LTO.cpp
+++ b/lld/ELF/LTO.cpp
@@ -248,7 +248,9 @@
// 2) Symbols that are used in regular objects.
// 3) C named sections if we have corresponding __start_/__stop_ symbol.
// 4) Symbols that are defined in bitcode files and used for dynamic linking.
+ // 5) Symbols that will be referenced after linker wrapping is performed.
r.VisibleToRegularObj = config->relocatable || sym->isUsedInRegularObj ||
+ sym->referencedAfterWrapping ||
(r.Prevailing && sym->includeInDynsym()) ||
usedStartStop.count(objSym.getSectionName());
// Identify symbols exported dynamically, and that therefore could be
diff --git a/lld/ELF/SymbolTable.cpp b/lld/ELF/SymbolTable.cpp
--- a/lld/ELF/SymbolTable.cpp
+++ b/lld/ELF/SymbolTable.cpp
@@ -39,7 +39,11 @@
idx2 = idx1;
idx1 = idx3;
- if (!real->isUsedInRegularObj && sym->isUndefined())
+ if (sym->isUsedInRegularObj)
+ wrap->isUsedInRegularObj = true;
+ if (real->isUsedInRegularObj)
+ sym->isUsedInRegularObj = true;
+ else if (sym->isUndefined())
sym->isUsedInRegularObj = false;
// Now renaming is complete, and no one refers to real. We drop real from
diff --git a/lld/ELF/Symbols.h b/lld/ELF/Symbols.h
--- a/lld/ELF/Symbols.h
+++ b/lld/ELF/Symbols.h
@@ -131,6 +131,11 @@
// This is also used to retain __wrap_foo when foo is referenced.
uint8_t referenced : 1;
+ // Used to track if this symbol will be referenced after wrapping is performed
+ // (i.e. this will be true for foo if __real_foo is referenced, and will be
+ // true for __wrap_foo if foo is referenced).
+ uint8_t referencedAfterWrapping : 1;
+
// True if this symbol is specified by --trace-symbol option.
uint8_t traced : 1;
@@ -240,12 +245,13 @@
binding(binding), type(type), stOther(stOther), symbolKind(k),
visibility(stOther & 3), isPreemptible(false),
isUsedInRegularObj(false), used(false), exportDynamic(false),
- inDynamicList(false), referenced(false), traced(false),
- hasVersionSuffix(false), isInIplt(false), gotInIgot(false),
- folded(false), needsTocRestore(false), scriptDefined(false),
- needsCopy(false), needsGot(false), needsPlt(false), needsTlsDesc(false),
- needsTlsGd(false), needsTlsGdToIe(false), needsGotDtprel(false),
- needsTlsIe(false), hasDirectReloc(false) {}
+ inDynamicList(false), referenced(false), referencedAfterWrapping(false),
+ traced(false), hasVersionSuffix(false), isInIplt(false),
+ gotInIgot(false), folded(false), needsTocRestore(false),
+ scriptDefined(false), needsCopy(false), needsGot(false),
+ needsPlt(false), needsTlsDesc(false), needsTlsGd(false),
+ needsTlsGdToIe(false), needsGotDtprel(false), needsTlsIe(false),
+ hasDirectReloc(false) {}
public:
// True if this symbol is in the Iplt sub-section of the Plt and the Igot
diff --git a/lld/test/ELF/invalid-plt-relocation.test b/lld/test/ELF/invalid-plt-relocation.test
deleted file mode 100644
--- a/lld/test/ELF/invalid-plt-relocation.test
+++ /dev/null
@@ -1,32 +0,0 @@
-# REQUIRES: x86
-
-# RUN: rm -rf %t && split-file %s %t
-# RUN: llvm-mc -triple x86_64-elf --filetype=obj -o %t/unwind.o %t/unwind.s
-# RUN: ld.lld -shared -o %t/libunwind.so -soname libunwind.so %t/unwind.o
-# RUN: llvm-as -o %t/resume.bc %t/resume.ll
-# RUN: not ld.lld -shared -o %t/libresume.so %t/resume.bc %t/libunwind.so \
-# RUN: --wrap _Unwind_Resume 2>&1 | FileCheck %s
-
-# CHECK: error: PLT relocation references symbol not present in dynamic symbol table: __wrap__Unwind_Resume
-
-#--- unwind.s
-.globl _Unwind_Resume
-.globl __wrap__Unwind_Resume
-_Unwind_Resume:
-__wrap__Unwind_Resume:
- retq
-
-#--- resume.ll
-target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
-target triple = "x86_64-unknown-linux-gnu"
-define dso_local void @_Z1fv() optnone noinline personality i8* bitcast (void ()* @throw to i8*) {
- invoke void @throw()
- to label %unreachable unwind label %lpad
-lpad:
- %1 = landingpad { i8*, i32 }
- cleanup
- resume { i8*, i32 } %1
-unreachable:
- unreachable
-}
-declare void @throw()
diff --git a/lld/test/ELF/lto/wrap-unreferenced-before-codegen.test b/lld/test/ELF/lto/wrap-unreferenced-before-codegen.test
new file mode 100644
--- /dev/null
+++ b/lld/test/ELF/lto/wrap-unreferenced-before-codegen.test
@@ -0,0 +1,92 @@
+# REQUIRES: x86
+## Verify that we can correctly wrap symbols produced only during LTO codegen
+## and unreferenced before then.
+
+# RUN: rm -rf %t && split-file %s %t
+# RUN: llvm-mc -triple x86_64-elf --filetype=obj -o %t/unwind.o %t/unwind.s
+# RUN: ld.lld -shared -o %t/libunwind.so -soname libunwind.so %t/unwind.o
+# RUN: llvm-as -o %t/resume.bc %t/resume.ll
+# RUN: ld.lld -shared -o %t/libresume.so -soname libresume.so %t/resume.bc \
+# RUN: %t/libunwind.so --wrap _Unwind_Resume
+# RUN: llvm-objdump --dynamic-reloc --disassemble %t/libresume.so | \
+# RUN: FileCheck --check-prefix=UNWIND-DISASM %s
+# RUN: llvm-readelf --dyn-syms %t/libresume.so | \
+# RUN: FileCheck --check-prefix=UNWIND-DYNSYM %s
+
+# UNWIND-DISASM: [[#%x,RELOC:]] R_X86_64_JUMP_SLOT __wrap__Unwind_Resume
+# UNWIND-DISASM-LABEL: <_Z1fv>:
+# UNWIND-DISASM: callq{{.*}}<__wrap__Unwind_Resume@plt>
+# UNWIND-DISASM-LABEL: <__wrap__Unwind_Resume@plt>:
+# UNWIND-DISASM-NEXT: jmpq *[[#]](%rip) # [[#%#x,RELOC]]
+
+# UNWIND-DYNSYM: Symbol table '.dynsym' contains 5 entries:
+# UNWIND-DYNSYM: NOTYPE LOCAL DEFAULT UND
+# UNWIND-DYNSYM-NEXT: NOTYPE GLOBAL DEFAULT UND throw
+# UNWIND-DYNSYM-NEXT: NOTYPE GLOBAL DEFAULT UND _Unwind_Resume
+# UNWIND-DYNSYM-NEXT: NOTYPE GLOBAL DEFAULT UND __wrap__Unwind_Resume
+# UNWIND-DYNSYM-NEXT: FUNC GLOBAL DEFAULT 9 _Z1fv
+
+# RUN: llvm-mc -triple x86_64-elf -filetype=obj -o %t/malloc.o %t/malloc.s
+# RUN: ld.lld -shared -o %t/libmalloc.so -soname libmalloc.so %t/malloc.o
+# RUN: llvm-mc -triple x86_64-elf -filetype=obj -o %t/emutls.o %t/emutls.s
+# RUN: llvm-as -o %t/usetls.bc %t/usetls.ll
+# RUN: ld.lld -shared -o %t/libusetls.so %t/usetls.bc %t/libmalloc.so \
+# RUN: --start-lib %t/emutls.o -mllvm -emulated-tls --wrap malloc
+# RUN: llvm-objdump --dynamic-reloc --disassemble %t/libusetls.so | \
+# RUN: FileCheck --check-prefix=USETLS-DISASM %s
+# RUN: llvm-readelf --dyn-syms %t/libusetls.so | \
+# RUN: FileCheck --check-prefix=USETLS-DYNSYM %s
+
+# USETLS-DISASM: [[#%x,RELOC:]] R_X86_64_JUMP_SLOT __wrap_malloc
+# USETLS-DISASM-LABEL: <__emutls_get_address>:
+# USETLS-DISASM-NEXT: jmp{{.*}}<__wrap_malloc@plt>
+# USETLS-DISASM-LABEL: <__wrap_malloc@plt>:
+# USETLS-DISASM-NEXT: jmpq *[[#]](%rip) # [[#%#x,RELOC]]
+
+# USETLS-DYNSYM: Symbol table '.dynsym' contains 6 entries:
+# USETLS-DYNSYM: NOTYPE LOCAL DEFAULT UND
+# USETLS-DYNSYM-NEXT: NOTYPE GLOBAL DEFAULT UND malloc
+# USETLS-DYNSYM-NEXT: NOTYPE GLOBAL DEFAULT UND __wrap_malloc
+# USETLS-DYNSYM-NEXT: FUNC GLOBAL DEFAULT 6 f
+# USETLS-DYNSYM-NEXT: NOTYPE GLOBAL DEFAULT 6 __emutls_get_address
+
+#--- unwind.s
+.globl _Unwind_Resume
+.globl __wrap__Unwind_Resume
+_Unwind_Resume:
+__wrap__Unwind_Resume:
+ retq
+
+#--- resume.ll
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+define dso_local void @_Z1fv() optnone noinline personality i8* bitcast (void ()* @throw to i8*) {
+ invoke void @throw()
+ to label %unreachable unwind label %lpad
+lpad:
+ %1 = landingpad { i8*, i32 }
+ cleanup
+ resume { i8*, i32 } %1
+unreachable:
+ unreachable
+}
+declare void @throw()
+
+#--- malloc.s
+.globl malloc
+malloc:
+ retq
+
+#--- emutls.s
+.globl __emutls_get_address
+__emutls_get_address:
+ jmp malloc@plt
+
+#--- usetls.ll
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+@x = dso_local thread_local global i32 0, align 4
+define dso_local i32 @f() {
+ %loaded = load i32, ptr @x, align 4
+ ret i32 %loaded
+}