diff options
| -rw-r--r-- | lld/ELF/Relocations.cpp | 11 | ||||
| -rw-r--r-- | lld/test/ELF/Inputs/i386-pic-plt.s | 4 | ||||
| -rw-r--r-- | lld/test/ELF/i386-pic-plt.s | 12 |
3 files changed, 27 insertions, 0 deletions
diff --git a/lld/ELF/Relocations.cpp b/lld/ELF/Relocations.cpp index c168b01d127..0f975be42c0 100644 --- a/lld/ELF/Relocations.cpp +++ b/lld/ELF/Relocations.cpp @@ -875,6 +875,17 @@ static RelExpr processRelocAux(InputSectionBase &Sec, RelExpr Expr, // that points to the real function is a dedicated got entry used by the // plt. That is identified by special relocation types (R_X86_64_JUMP_SLOT, // R_386_JMP_SLOT, etc). + + // For position independent executable on i386, the plt entry requires ebx + // to be set. This causes two problems: + // * If some code has a direct reference to a function, it was probably + // compiled without -fPIE/-fPIC and doesn't maintain ebx. + // * If a library definition gets preempted to the executable, it will have + // the wrong ebx value. + if (Config->Pie && Config->EMachine == EM_386) + errorOrWarn("symbol '" + toString(Sym) + + "' cannot be preempted; recompile with -fPIE" + + getLocation(Sec, Sym, Offset)); Sym.NeedsPltAddr = true; Expr = toPlt(Expr); Sec.Relocations.push_back({Expr, Type, Offset, Addend, &Sym}); diff --git a/lld/test/ELF/Inputs/i386-pic-plt.s b/lld/test/ELF/Inputs/i386-pic-plt.s new file mode 100644 index 00000000000..a7a812194fa --- /dev/null +++ b/lld/test/ELF/Inputs/i386-pic-plt.s @@ -0,0 +1,4 @@ + .global foo + .type foo, @function +foo: + nop diff --git a/lld/test/ELF/i386-pic-plt.s b/lld/test/ELF/i386-pic-plt.s new file mode 100644 index 00000000000..0d32436899a --- /dev/null +++ b/lld/test/ELF/i386-pic-plt.s @@ -0,0 +1,12 @@ +// REQUIRES: x86 +// RUN: llvm-mc -filetype=obj -triple=i386-pc-linux %s -o %t.o +// RUN: llvm-mc -filetype=obj -triple=i386-pc-linux %p/Inputs/i386-pic-plt.s -o %t2.o +// RUN: ld.lld -shared %t2.o -o %t2.so +// RUN: ld.lld %t.o %t2.so -o %t +// RUN: not ld.lld %t.o %t2.so -o %t -pie 2>&1 | FileCheck %s + +// CHECK: error: symbol 'foo' cannot be preempted; recompile with -fPIE + +.global _start +_start: + call foo |
