[PATCH] D66704: [ELF] Error if --strip-all and --emit-relocs are used together

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
MaskRay added reviewers: grimar, peter.smith, ruiu.
Herald added subscribers: llvm-commits, arichardson, emaste.
Herald added a reviewer: espindola.
Herald added a project: LLVM.

--strip-all suppresses the creation of in.symtab
This can cause a null pointer dereference in OutputSection::finalize

  // --emit-relocs => copyRelocs is true
  if (!config->copyRelocs || (type != SHT_RELA && type != SHT_REL))
    return;
  ...
  link = in.symTab->getParent()->sectionIndex; // in.symTab is null

Let's just disallow the combination.

In some cases:

- ld.bfd: final link failed: invalid operation
- gold: internal error in set_no_output_symtab_entry, at ../../gold/object.h:1814


Repository:
  rLLD LLVM Linker

https://reviews.llvm.org/D66704

Files:
  ELF/Driver.cpp
  test/ELF/strip-all.s


Index: test/ELF/strip-all.s
===================================================================
--- test/ELF/strip-all.s
+++ test/ELF/strip-all.s
@@ -21,6 +21,9 @@
 #RUN: ld.lld %t.o -s -o %t1
 #RUN: llvm-objdump -section-headers %t1 | FileCheck %s -check-prefix AFTER
 
+# RUN: not ld.lld %t.o --strip-all --emit-relocs -o /dev/null 2>&1 | FileCheck --check-prefix=ERR %s
+# ERR: error: --strip-all and --emit-relocs may not be used together
+
 # exits with return code 42 on linux
 .globl _start
 _start:
Index: ELF/Driver.cpp
===================================================================
--- ELF/Driver.cpp
+++ ELF/Driver.cpp
@@ -314,6 +314,9 @@
   if (!config->relocatable && !config->defineCommon)
     error("-no-define-common not supported in non relocatable output");
 
+  if (config->strip == StripPolicy::All && config->emitRelocs)
+    error("--strip-all and --emit-relocs may not be used together");
+
   if (config->zText && config->zIfuncNoplt)
     error("-z text and -z ifunc-noplt may not be used together");
 


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