From 229871c6966c49c512f7343b282606d1327393cf Mon Sep 17 00:00:00 2001
From: Alexander Richardson <arichardson.kde@gmail.com>
Date: Fri, 22 Sep 2017 09:30:40 +0000
Subject: [PATCH] [obj2yaml] Don't crash for input files without symbol table

Summary: Previously we would dereference Symtab without checking for null.

Reviewers: davide, atanasyan, rafael

Reviewed By: davide, atanasyan

Differential Revision: https://reviews.llvm.org/D38080

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313970 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/tools/obj2yaml/Inputs/crt1.o       | Bin 0 -> 2712 bytes
 test/tools/obj2yaml/missing_symtab.test |   5 +++++
 tools/obj2yaml/elf2yaml.cpp             |   2 ++
 3 files changed, 7 insertions(+)
 create mode 100755 test/tools/obj2yaml/Inputs/crt1.o
 create mode 100644 test/tools/obj2yaml/missing_symtab.test

diff --git a/test/tools/obj2yaml/Inputs/crt1.o b/test/tools/obj2yaml/Inputs/crt1.o
new file mode 100755
index 0000000000000000000000000000000000000000..2b000ab9ae836ec8aebb7dccf4467bfee2d4c381
GIT binary patch
literal 2712
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YBQN|(PCZ2CPFSB3dDn!5@1lSB2Yp<Z&j0`b

literal 0
HcmV?d00001

diff --git a/test/tools/obj2yaml/missing_symtab.test b/test/tools/obj2yaml/missing_symtab.test
new file mode 100644
index 00000000000..b992931a0db
--- /dev/null
+++ b/test/tools/obj2yaml/missing_symtab.test
@@ -0,0 +1,5 @@
+# RUN: obj2yaml %S/Inputs/crt1.o | FileCheck %s
+# test that we don't crash when passed object files without a symbol table
+# CHECK-LABEL: FileHeader:
+# CHECK-LABEL: Sections:
+# CHECK-LABEL: Symbols:
diff --git a/tools/obj2yaml/elf2yaml.cpp b/tools/obj2yaml/elf2yaml.cpp
index 8997a5c4211..8c94843788f 100644
--- a/tools/obj2yaml/elf2yaml.cpp
+++ b/tools/obj2yaml/elf2yaml.cpp
@@ -188,6 +188,8 @@ template <class ELFT> ErrorOr<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
   }
 
   // Dump symbols
+  if (!Symtab)
+    return Y.release(); // if the symbol table is missing return early
   auto StrTableOrErr = Obj.getStringTableForSymtab(*Symtab);
   if (!StrTableOrErr)
     return errorToErrorCode(StrTableOrErr.takeError());
-- 
2.40.0