diff options
| -rw-r--r-- | lld/ELF/SyntheticSections.cpp | 16 | ||||
| -rw-r--r-- | lld/test/ELF/mips-tls-64-pic-local-variable.s | 49 |
2 files changed, 63 insertions, 2 deletions
diff --git a/lld/ELF/SyntheticSections.cpp b/lld/ELF/SyntheticSections.cpp index 4195ed9a2e8..efaca97ede7 100644 --- a/lld/ELF/SyntheticSections.cpp +++ b/lld/ELF/SyntheticSections.cpp @@ -922,9 +922,17 @@ template <class ELFT> void MipsGotSection::build() { continue; InX::RelaDyn->addReloc(Target->TlsModuleIndexRel, this, Offset, S); } else { - if (!P.first->IsPreemptible) + // When building a shared library we still need a dynamic relocation + // for the module index. Therefore only checking for + // S->IsPreemptible is not sufficient (this happens e.g. for + // thread-locals that have been marked as local through a linker script) + if (!S->IsPreemptible && !Config->Pic) continue; InX::RelaDyn->addReloc(Target->TlsModuleIndexRel, this, Offset, S); + // However, we can skip writing the TLS offset reloc for non-preemptible + // symbols since it is known even in shared libraries + if (!S->IsPreemptible) + continue; Offset += Config->Wordsize; InX::RelaDyn->addReloc(Target->TlsOffsetRel, this, Offset, S); } @@ -1030,7 +1038,11 @@ void MipsGotSection::writeTo(uint8_t *Buf) { if (P.first == nullptr && !Config->Pic) Write(P.second, nullptr, 1); else if (P.first && !P.first->IsPreemptible) { - Write(P.second, nullptr, 1); + // If we are emitting PIC code with relocations we mustn't write + // anything to the GOT here. When using Elf_Rel relocations the value + // one will be treated as an addend and will cause crashes at runtime + if (!Config->Pic) + Write(P.second, nullptr, 1); Write(P.second + 1, P.first, -0x8000); } } diff --git a/lld/test/ELF/mips-tls-64-pic-local-variable.s b/lld/test/ELF/mips-tls-64-pic-local-variable.s new file mode 100644 index 00000000000..04d916f42c6 --- /dev/null +++ b/lld/test/ELF/mips-tls-64-pic-local-variable.s @@ -0,0 +1,49 @@ +# REQUIRES: mips +# MIPS TLS variables that are marked as local by a version script were previously +# writing values to the GOT that caused runtime crashes. This was happending when +# linking jemalloc_tsd.c in FreeBSD libc. Check that we do the right thing now: + +# RUN: llvm-mc -filetype=obj -triple=mips64-unknown-freebsd %s -o %t.o +# RUN: echo "{ global: foo; local: *; };" > %t.script +# RUN: ld.lld --version-script %t.script -shared %t.o -o %t.so +# RUN: llvm-objdump --section=.got -s %t.so | FileCheck %s -check-prefix GOT +# RUN: llvm-readobj -r %t.so | FileCheck %s -check-prefix RELOCS + +# GOT: Contents of section .got: +# GOT-NEXT: 20000 00000000 00000000 80000000 00000000 +# GOT-NEXT: 20010 00000000 00000000 00000000 00000000 +# GOT-NEXT: 20020 ffffffff ffff8000 + +# RELOCS: Section ({{.+}}) .rel.dyn { +# RELOCS-NEXT: 0x20018 R_MIPS_TLS_DTPMOD64/R_MIPS_NONE/R_MIPS_NONE +# RELOCS-NEXT: } + +# Test case generated using clang -mcpu=mips4 -target mips64-unknown-freebsd12.0 -fpic -O -G0 -EB -mabi=n64 -msoft-float -std=gnu99 -S %s -o %t.s +# from the following source: +# +# _Thread_local int x; +# int foo() { return x; } +# + .text + .globl foo + .p2align 3 + .type foo,@function + .ent foo +foo: + lui $1, %hi(%neg(%gp_rel(foo))) + daddu $1, $1, $25 + daddiu $gp, $1, %lo(%neg(%gp_rel(foo))) + ld $25, %call16(__tls_get_addr)($gp) + jalr $25 + daddiu $4, $gp, %tlsgd(x) + .end foo + + .type x,@object + .section .tbss,"awT",@nobits + .globl x + .p2align 2 +x: + .4byte 0 + .size x, 4 + + |
