From 86611a078f1d9d16caf1951b22763fa322dcce73 Mon Sep 17 00:00:00 2001
From: Petr Hosek <phosek@chromium.org>
Date: Tue, 25 Apr 2017 18:56:33 +0000
Subject: [PATCH] [llvm-objdump] Don't attempt to print lines beyond the end of
 file

This may trigger a segfault in llvm-objdump when the line number stored
in debug infromation points beyond the end of file; lines in LineBuffer
are stored in std::vector which is allocated in chunks, so even if the
debug info points beyond the end of the file, this doesn't necessarily
trigger the segfault unless the line number points beyond the allocated
space.

Differential Revision: https://reviews.llvm.org/D32466

llvm-svn: 301347
---
 .../X86/Inputs/debug-info-fileinfo.exe.elf-x86_64  | Bin 0 -> 1540 bytes
 .../llvm-objdump/X86/debug-info-fileinfo.test      |  27 +++++++++++++++++++++
 llvm/tools/llvm-objdump/llvm-objdump.cpp           |   5 +++-
 3 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 llvm/test/tools/llvm-objdump/X86/Inputs/debug-info-fileinfo.exe.elf-x86_64
 create mode 100644 llvm/test/tools/llvm-objdump/X86/debug-info-fileinfo.test

diff --git a/llvm/test/tools/llvm-objdump/X86/Inputs/debug-info-fileinfo.exe.elf-x86_64 b/llvm/test/tools/llvm-objdump/X86/Inputs/debug-info-fileinfo.exe.elf-x86_64
new file mode 100644
index 0000000000000000000000000000000000000000..2074886c66560330e57707ffc307a485042836b1
GIT binary patch
literal 1540
zcmbtU&2G~`5T3P5<RCyzL84L*I1-3dB6bQYRDh~nKmu_B32_T{v-xQqZ{%G^i4=)G
zLXVs|^A^4F1RQw=4qUh}`<JBK^u$WuneUr#ch<8%UtYa??GXaDd2k34O`)wQ-2;5}
z6g1ocYT8hRiqc+NhR|ypr0v`wYXL&VoS&VYKSEDW8z|1^+)(Ip_Zul43)F(Ger|HU
z$;YMOahIlLzd6i%teMgo%e&3qFr(22h)Z6?89Pd{xX)NWqw#=^XgnS;PEX>aEXn)L
zESrpC)d|W)EEvnU!cCSQcgxW@{&esZls25uf)809?nkYt6*fds<|pBk*52c1d%Iyn
zPqO6pcY&OGTqK21RjcCP*gpUtydGn!8aI%i*(&+~q((OH*2os|gPq_(a2u=bT}SY|
z@}g2B4^i%K%UX@`^WZ)9g#5jA6MMC-SSg|l18`+!aL|=8S?UcBs-9i!wqFhFb&p^M
zi1=(Ik`%2dv>jMa(5Zk(P1{KdtS#jh%Du6ElBNZnSd<NOiuwM(?cfx0<rOoPUHsHw
z_l&u?ZpIt=!q{`%S}@v?xmKHuyPS-FH=;krTH|V8V!-93_M0IacA&AY_AT-*C#63O
zDa<%)Tx|^lc=#^0Lw#Z4qZ4t*OKhYUls`?O^$iA)H(&0NegOc~QAR9p$GZH#%wuyO
z<EzchzZ!FWA1h<e!)gpK;VNAC{@Rtu^|_};5AosRizr#SzO6NR<$rG?KZnogE!!P*
nrGD`en2@Z`I{iJvpE~nEN543oPRhCQ<xA6{-9#j4@-F-X!7G}b

literal 0
HcmV?d00001

diff --git a/llvm/test/tools/llvm-objdump/X86/debug-info-fileinfo.test b/llvm/test/tools/llvm-objdump/X86/debug-info-fileinfo.test
new file mode 100644
index 0000000..2c51e0b
--- /dev/null
+++ b/llvm/test/tools/llvm-objdump/X86/debug-info-fileinfo.test
@@ -0,0 +1,27 @@
+# Check that debug info line number pointing beyond the end of the file
+# doesn't cause a segmentation fault in llvm-objdump.
+
+# To rebuild the input: clang -g debug-info-fileinfo.S -o debug-info-fileinfo.exe -nostdlib
+
+# RUN: llvm-objdump -S %p/Inputs/debug-info-fileinfo.exe.elf-x86_64 | FileCheck %s
+
+# CHECK: Disassembly of section .text:
+# CHECK: _start
+# CHECK-NEXT:   400078:       c3      retq
+# CHECK: foo
+# CHECK-NEXT:   400079:       90      nop
+# CHECK-NEXT:   40007a:       90      nop
+# CHECK-NEXT:   40007b:       c3      retq
+
+.text
+
+.global _start; .type _start, STT_FUNC; _start:
+    ret
+
+.global foo; .type foo, STT_FUNC; foo:
+    # foo
+    # bar
+    # baz
+    nop
+    nop
+    ret
diff --git a/llvm/tools/llvm-objdump/llvm-objdump.cpp b/llvm/tools/llvm-objdump/llvm-objdump.cpp
index 613d064..18fa0e0 100644
--- a/llvm/tools/llvm-objdump/llvm-objdump.cpp
+++ b/llvm/tools/llvm-objdump/llvm-objdump.cpp
@@ -485,10 +485,13 @@ void SourcePrinter::printSourceLine(raw_ostream &OS, uint64_t Address,
     auto FileBuffer = SourceCache.find(LineInfo.FileName);
     if (FileBuffer != SourceCache.end()) {
       auto LineBuffer = LineCache.find(LineInfo.FileName);
-      if (LineBuffer != LineCache.end())
+      if (LineBuffer != LineCache.end()) {
+        if (LineInfo.Line > LineBuffer->second.size())
+          return;
         // Vector begins at 0, line numbers are non-zero
         OS << Delimiter << LineBuffer->second[LineInfo.Line - 1].ltrim()
            << "\n";
+      }
     }
   }
   OldLineInfo = LineInfo;
-- 
2.7.4