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author | Fangrui Song <i@maskray.me> | 2023-12-12 10:14:36 -0800 |
---|---|---|
committer | GitHub <noreply@github.com> | 2023-12-12 10:14:36 -0800 |
commit | 42e4967140e345923a43f809ba69be57200f46ae (patch) | |
tree | d872dadc2d15c928623aae8a765c10424c34206f | |
parent | 766bf140ffd6ce420426b80aa2cce0cb0d25ab7d (diff) | |
download | llvm-42e4967140e345923a43f809ba69be57200f46ae.zip llvm-42e4967140e345923a43f809ba69be57200f46ae.tar.gz llvm-42e4967140e345923a43f809ba69be57200f46ae.tar.bz2 |
[ELF] Don't create copy relocation/canonical PLT entry for a defined symbol (#75095)
Copy relocations and canonical PLT entries are for symbols defined in a
DSO. Currently we create them even for a `Defined`, possibly leading to
an output that won't work at run-time (e.g. R_X86_64_JUMP_SLOT
referencing a null symbol).
```
% cat a.s
.globl _start, main
.type main, @function
_start: main: ret
.rodata
.quad main
% clang -fuse-ld=lld -pie -nostdlib a.s
% readelf -Wr a.out
Relocation section '.rela.plt' at offset 0x290 contains 1 entry:
Offset Info Type Symbol's Value Symbol's Name + Addend
00000000000033b8 0000000000000007 R_X86_64_JUMP_SLOT 12b0
```
Report an error instead for the default `-z text` mode. GNU ld reports
an error in `-z text` mode as well.
-rw-r--r-- | lld/ELF/Relocations.cpp | 4 | ||||
-rw-r--r-- | lld/test/ELF/got32-i386.s | 2 | ||||
-rw-r--r-- | lld/test/ELF/got32x-i386.s | 2 | ||||
-rw-r--r-- | lld/test/ELF/x86-64-dyn-rel-error.s | 6 |
4 files changed, 7 insertions, 7 deletions
diff --git a/lld/ELF/Relocations.cpp b/lld/ELF/Relocations.cpp index fe3d7f4..210b4d1 100644 --- a/lld/ELF/Relocations.cpp +++ b/lld/ELF/Relocations.cpp @@ -1158,8 +1158,8 @@ void RelocationScanner::processAux(RelExpr expr, RelType type, uint64_t offset, } // When producing an executable, we can perform copy relocations (for - // STT_OBJECT) and canonical PLT (for STT_FUNC). - if (!config->shared) { + // STT_OBJECT) and canonical PLT (for STT_FUNC) if sym is defined by a DSO. + if (!config->shared && sym.isShared()) { if (!canDefineSymbolInExecutable(sym)) { errorOrWarn("cannot preempt symbol: " + toString(sym) + getLocation(*sec, sym, offset)); diff --git a/lld/test/ELF/got32-i386.s b/lld/test/ELF/got32-i386.s index f44719f..9416e36 100644 --- a/lld/test/ELF/got32-i386.s +++ b/lld/test/ELF/got32-i386.s @@ -20,4 +20,4 @@ _start: # CHECK-NEXT: 4010f5: 8b 1d {{.*}} movl 4202748, %ebx # RUN: not ld.lld %t.o -o /dev/null -pie 2>&1 | FileCheck %s --check-prefix=ERR -# ERR: error: symbol 'foo' cannot be preempted; recompile with -fPIE +# ERR: error: relocation R_386_GOT32 cannot be used against symbol 'foo'; recompile with -fPIC diff --git a/lld/test/ELF/got32x-i386.s b/lld/test/ELF/got32x-i386.s index fb12d99..3b19de9 100644 --- a/lld/test/ELF/got32x-i386.s +++ b/lld/test/ELF/got32x-i386.s @@ -43,4 +43,4 @@ # RUN: not ld.lld %S/Inputs/i386-got32x-baseless.elf -o /dev/null -pie 2>&1 | \ # RUN: FileCheck %s --check-prefix=ERR -# ERR-COUNT-2: error: symbol 'foo' cannot be preempted; recompile with -fPIE +# ERR-COUNT-2: error: relocation R_386_GOT32X cannot be used against symbol 'foo'; recompile with -fPIC diff --git a/lld/test/ELF/x86-64-dyn-rel-error.s b/lld/test/ELF/x86-64-dyn-rel-error.s index edc2875..a03adf8 100644 --- a/lld/test/ELF/x86-64-dyn-rel-error.s +++ b/lld/test/ELF/x86-64-dyn-rel-error.s @@ -3,7 +3,7 @@ # RUN: llvm-mc -filetype=obj -triple=x86_64 %p/Inputs/shared.s -o %t2.o # RUN: ld.lld %t2.o -shared -o %t2.so --threads=1 # RUN: not ld.lld -pie %t.o %t2.so -o /dev/null --threads=1 2>&1 | FileCheck %s -# RUN: not ld.lld -shared %t.o %t2.so -o /dev/null --threads=1 2>&1 | FileCheck %s --check-prefixes=CHECK,SHARED +# RUN: not ld.lld -shared %t.o %t2.so -o /dev/null --threads=1 2>&1 | FileCheck %s # CHECK: error: relocation R_X86_64_32 cannot be used against symbol 'zed'; recompile with -fPIC # CHECK-NEXT: >>> defined in {{.*}}.so @@ -14,8 +14,8 @@ # CHECK-NEXT: >>> referenced by {{.*}}.o:(.data+0x4) # CHECK-EMPTY: # CHECK-NEXT: error: relocation R_X86_64_64 cannot be used against symbol '_start'; recompile with -fPIC -# SHARED: error: relocation R_X86_64_64 cannot be used against symbol 'main'; recompile with -fPIC -# SHARED: error: relocation R_X86_64_64 cannot be used against symbol 'data'; recompile with -fPIC +# CHECK: error: relocation R_X86_64_64 cannot be used against symbol 'main'; recompile with -fPIC +# CHECK: error: relocation R_X86_64_64 cannot be used against symbol 'data'; recompile with -fPIC # CHECK-NOT: error: # RUN: ld.lld --noinhibit-exec %t.o %t2.so -o /dev/null 2>&1 | FileCheck --check-prefix=WARN %s |