[lld] r339904 - [ELF] mergeSections: remove non-alive MergeInputSection

[Fangrui Song via llvm-commits]

Author: maskray
Date: Thu Aug 16 10:22:02 2018
New Revision: 339904

URL: http://llvm.org/viewvc/llvm-project?rev=339904&view=rev
Log:
[ELF] mergeSections: remove non-alive MergeInputSection

Summary: This makes it conform to what the comment says. Otherwise when getErrPlace() is called afterwards, cast<InputSection>(D) will cause incompatible cast as MergeInputSection is not a subclass of InputSection.

Reviewers: ruiu, grimar, espindola, pcc

Reviewed By: grimar

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D50742

Modified:
    lld/trunk/ELF/SyntheticSections.cpp
    lld/trunk/test/ELF/x86-64-reloc-error2.s

Modified: lld/trunk/ELF/SyntheticSections.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/SyntheticSections.cpp?rev=339904&r1=339903&r2=339904&view=diff
==============================================================================
--- lld/trunk/ELF/SyntheticSections.cpp (original)
+++ lld/trunk/ELF/SyntheticSections.cpp Thu Aug 16 10:22:02 2018
@@ -2929,8 +2929,10 @@ void elf::mergeSections() {
 
     // We do not want to handle sections that are not alive, so just remove
     // them instead of trying to merge.
-    if (!MS->Live)
+    if (!MS->Live) {
+      S = nullptr;
       continue;
+    }
 
     StringRef OutsecName = getOutputSectionName(MS);
     uint32_t Alignment = std::max<uint32_t>(MS->Alignment, MS->Entsize);

Modified: lld/trunk/test/ELF/x86-64-reloc-error2.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/x86-64-reloc-error2.s?rev=339904&r1=339903&r2=339904&view=diff
==============================================================================
--- lld/trunk/test/ELF/x86-64-reloc-error2.s (original)
+++ lld/trunk/test/ELF/x86-64-reloc-error2.s Thu Aug 16 10:22:02 2018
@@ -1,14 +1,18 @@
 # REQUIRES: x86
 # RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
-# RUN: not ld.lld %t.o -o /dev/null 2>&1 | FileCheck %s
+# RUN: not ld.lld --entry=func --gc-sections %t.o -o /dev/null 2>&1 | FileCheck %s
 
 ## Check we are able to find a function symbol that encloses
 ## a given location when reporting error messages.
 # CHECK: {{.*}}.o:(function func): relocation R_X86_64_32S out of range: -281474974609408 is not in [-2147483648, 2147483647]
 
+# This mergeable section will be garbage collected. We had a crash issue in that case. Test it.
+.section .rodata.str1,"aMS", at progbits,1
+.asciz "a"
+
 .section .text.func, "ax", %progbits
 .globl func
 .type func, at function
-.size func, 0x10
 func:
- movq func - 0x1000000000000, %rdx
+  movq $func - 0x1000000000000, %rdx
+.size func, .-func