diff --git a/lld/MachO/UnwindInfoSection.cpp b/lld/MachO/UnwindInfoSection.cpp --- a/lld/MachO/UnwindInfoSection.cpp +++ b/lld/MachO/UnwindInfoSection.cpp @@ -251,6 +251,11 @@ for (size_t i = 0; i < isec->relocs.size(); ++i) { Reloc &r = isec->relocs[i]; assert(target->hasAttr(r.type, RelocAttrBits::UNSIGNED)); + // Since compact unwind sections aren't part of the inputSections vector, + // they don't get canonicalized by scanRelocations(), so we have to do the + // canonicalization here. + if (auto *referentIsec = r.referent.dyn_cast()) + r.referent = referentIsec->canonical(); // Functions and LSDA entries always reside in the same object file as the // compact unwind entries that references them, and thus appear as section diff --git a/lld/test/MachO/icf-only-lsda-folded.s b/lld/test/MachO/icf-only-lsda-folded.s new file mode 100644 --- /dev/null +++ b/lld/test/MachO/icf-only-lsda-folded.s @@ -0,0 +1,65 @@ +# REQUIRES: x86 +# RUN: rm -rf %t; split-file %s %t + +## This is a regression test. Previously, we would emit a bogus LSDA pointer if +## the following conditions held: +## * ICF and dead-strip were both done +## * There exist two functions different compact unwind encodings, but the +## same LSDA +## +## Essentially, we'd neglected to canonicalize the LSDA pointer after ICF, but +## the broken output would only appear if the compact unwind entry that pointed +## to it was not itself folded. + +# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/test.s -o %t/test.o +# RUN: %lld -dylib -dead_strip --icf=all %t/test.o -o %t/test +# RUN: llvm-objdump --macho --syms --unwind-info %t/test | FileCheck %s + +# CHECK: SYMBOL TABLE: +## Sanity check: Verify that the LSDAs are dedup'ed +# CHECK-NEXT: [[#%.16x, EXC:]] l O __TEXT,__gcc_except_tab _exception0 +# CHECK-NEXT: [[#EXC]] l O __TEXT,__gcc_except_tab _exception1 +## But that the functions themselves aren't +# CHECK-NEXT: [[#%.16x, FOO:]] g F __TEXT,__text _foo +# CHECK-NEXT: [[#%.16x, BAR:FOO + 1]] g F __TEXT,__text _bar + +## _foo and _bar should share the same LSDA. We would previously emit a bogus +## address for _bar's LSDA. +# CHECK: Contents of __unwind_info section: +# CHECK: LSDA descriptors: +# CHECK-NEXT: [0]: function offset=0x[[#%.8x, FOO]], LSDA offset=0x[[#%.8x, EXC]] +# CHECK-NEXT: [1]: function offset=0x[[#%.8x, BAR]], LSDA offset=0x[[#%.8x, EXC]] + +## But there should be two distinct encodings, one for each function +# CHECK: Second level indices: +# CHECK-NEXT: Second level index[0]: +# CHECK-NEXT: [0]: function offset=0x[[#%.8x, FOO]], encoding[0]=0x42020000 +# CHECK-NEXT: [1]: function offset=0x[[#%.8x, BAR]], encoding[1]=0x42010000 + +#--- test.s +.text +.globl _foo, _bar + +_foo: + .cfi_startproc + .cfi_lsda 16, _exception0 + .cfi_def_cfa_offset 16 + ret + .cfi_endproc + +_bar: + .cfi_startproc + .cfi_lsda 16, _exception1 + .cfi_def_cfa_offset 8 ## ensure _bar's CUE doesn't get folded with _foo's + ret + .cfi_endproc + +.section __TEXT,__gcc_except_tab + +_exception0: + .quad 0x1234 + +_exception1: + .quad 0x1234 + +.subsections_via_symbols