Fix a crash bug in --emit-relocs

Fixes #950
rui314 · Jan 9, 2023 · e17d7da · e17d7da
1 parent d4e40a3
commit e17d7da
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Showing 2 changed files with 38 additions and 3 deletions.
diff --git a/elf/output-chunks.cc b/elf/output-chunks.cc
@@ -3026,9 +3026,18 @@ void RelocSection<E>::copy_buf(Context<E> &ctx) {
         addend = frag->offset + sym.value + get_addend(isec, rel);
       } else {
         InputSection<E> *target = sym.get_input_section();
-        OutputSection<E> *osec = target->output_section;
-        out.r_sym = osec->shndx;
-        addend = get_addend(isec, rel) + target->offset;
+
+        if (OutputSection<E> *osec = target->output_section) {
+          out.r_sym = osec->shndx;
+          addend = get_addend(isec, rel) + target->offset;
+        } else if (isec.name() == ".eh_frame") {
+          out.r_sym = ctx.eh_frame->shndx;
+          addend = get_addend(isec, rel);
+        } else {
+          // This is usually a dead debug section referring a
+          // COMDAT-eliminated section.
+          addend = 0;
+        }
       }
 
       if constexpr (E::is_rela) {

diff --git a/test/elf/emit-relocs-dead-sections.sh b/test/elf/emit-relocs-dead-sections.sh
@@ -0,0 +1,26 @@
+#!/bin/bash
+. $(dirname $0)/common.inc
+
+[ $MACHINE = sh4 ] && skip
+
+cat <<EOF | $CXX -o $t/a.o -c -fPIC -xc++ -g -ffunction-sections -
+#include <iostream>
+struct Foo {
+  Foo() { std::cout << "Hello world\n"; }
+};
+
+Foo x;
+EOF
+
+cat <<EOF | $CXX -o $t/b.o -c -fPIC -xc++ -g -ffunction-sections -
+#include <iostream>
+struct Foo {
+  Foo() { std::cout << "Hello world\n"; }
+};
+
+Foo y;
+int main() {}
+EOF
+
+$CXX -B. -o $t/exe $t/a.o $t/b.o -Wl,-emit-relocs
+$QEMU $t/exe | grep -q 'Hello world'