diff options
| -rw-r--r-- | lld/COFF/Chunks.cpp | 7 | ||||
| -rw-r--r-- | lld/test/COFF/Inputs/comdat-jumptable2.s | 35 | ||||
| -rw-r--r-- | lld/test/COFF/comdat-jumptable.s | 70 |
3 files changed, 111 insertions, 1 deletions
diff --git a/lld/COFF/Chunks.cpp b/lld/COFF/Chunks.cpp index dc471117981..eb90bd7ba77 100644 --- a/lld/COFF/Chunks.cpp +++ b/lld/COFF/Chunks.cpp @@ -351,7 +351,12 @@ void SectionChunk::writeTo(uint8_t *Buf) const { check(File->getCOFFObj()->getSymbol(Rel.SymbolTableIndex)); StringRef Name; File->getCOFFObj()->getSymbolName(Sym, Name); - error("relocation against symbol in discarded section: " + Name); + + // MinGW mode object files (built by GCC) can have leftover sections + // with relocations against discarded comdat sections. Such sections + // are left as is, with relocations untouched. + if (!Config->MinGW) + error("relocation against symbol in discarded section: " + Name); continue; } // Get the output section of the symbol for this relocation. The output diff --git a/lld/test/COFF/Inputs/comdat-jumptable2.s b/lld/test/COFF/Inputs/comdat-jumptable2.s new file mode 100644 index 00000000000..8990d4c0d7f --- /dev/null +++ b/lld/test/COFF/Inputs/comdat-jumptable2.s @@ -0,0 +1,35 @@ + .section .text@comdatfunc, "x" + .linkonce discard + .globl comdatfunc +comdatfunc: + leaq .Ljumptable(%rip), %rax + movslq (%rax, %rcx, 4), %rcx + addq %rcx, %rax + jmp *%rax + + .section .rdata, "dr" + .long 0xcccccccc +.Ljumptable: + .long .Ltail1-.Ljumptable + .long .Ltail2-.Ljumptable + .long .Ltail3-.Ljumptable + .long 0xdddddddd + + .section .text@comdatfunc, "x" +# If assembled with binutils, the following line can be kept in: +# .linkonce discard +.Ltail1: + movl $1, %eax + ret +.Ltail2: + movl $2, %eax + ret +.Ltail3: + movl $3, %eax + ret + + .text + .globl otherfunc +otherfunc: + call comdatfunc + ret diff --git a/lld/test/COFF/comdat-jumptable.s b/lld/test/COFF/comdat-jumptable.s new file mode 100644 index 00000000000..31a7c5f6bcd --- /dev/null +++ b/lld/test/COFF/comdat-jumptable.s @@ -0,0 +1,70 @@ +# REQUIRES: x86 +# RUN: llvm-mc -triple=x86_64-windows-gnu %s -filetype=obj -o %t1.obj +# RUN: llvm-mc -triple=x86_64-windows-gnu %S/Inputs/comdat-jumptable2.s -filetype=obj -o %t2.obj + +# RUN: llvm-objdump -s %t1.obj | FileCheck --check-prefix=OBJ1 %s +# RUN: llvm-objdump -s %t2.obj | FileCheck --check-prefix=OBJ2 %s + +# RUN: lld-link -lldmingw -entry:main %t1.obj %t2.obj -out:%t.exe +# RUN: llvm-objdump -s %t.exe | FileCheck --check-prefix=EXE %s + +# Test linking cases where comdat functions have an associated jump table +# in a non-comdat rdata (which GCC produces for functions with jump tables). +# In these cases, ld.bfd keeps all rdata sections, but the relocations that +# refer to discarded comdat sections just are emitted as they were originally. + +# In real scenarios, the jump table .rdata section should be identical across +# all object files; here it is different to illustrate more clearly what +# the linker actually does. + +# OBJ1: Contents of section .rdata: +# OBJ1: 0000 aaaaaaaa 14000000 1e000000 28000000 +# OBJ1: 0010 bbbbbbbb + +# OBJ2: Contents of section .rdata: +# OBJ2: 0000 cccccccc 14000000 1e000000 28000000 +# OBJ2: 0010 dddddddd + +# EXE: Contents of section .rdata: +# EXE: 140002000 aaaaaaaa 0c100000 12100000 18100000 +# EXE: 140002010 bbbbbbbb cccccccc 14000000 1e000000 +# EXE: 140002020 28000000 dddddddd + + + .section .text@comdatfunc, "x" + .linkonce discard + .globl comdatfunc +comdatfunc: + leaq .Ljumptable(%rip), %rax + movslq (%rax, %rcx, 4), %rcx + addq %rcx, %rax + jmp *%rax + + .section .rdata, "dr" + .long 0xaaaaaaaa +.Ljumptable: + .long .Ltail1-.Ljumptable + .long .Ltail2-.Ljumptable + .long .Ltail3-.Ljumptable + .long 0xbbbbbbbb + + .section .text@comdatfunc, "x" +# If assembled with binutils, the following line can be kept in: +# .linkonce discard +.Ltail1: + movl $1, %eax + ret +.Ltail2: + movl $2, %eax + ret +.Ltail3: + movl $3, %eax + ret + + + .text + .globl main +main: + call comdatfunc + call otherfunc + ret |
