From 41a66df74f2b7df77d7132e2d71b6df448015f59 Mon Sep 17 00:00:00 2001
From: David Majnemer <david.majnemer@gmail.com>
Date: Sat, 30 Jan 2016 00:36:09 +0000
Subject: [PATCH] [CodeView] Properly handle empty line tables

Don't crash when there are no appropriate line table entries for a given
function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259277 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/MC/MCCodeView.h      | 14 +++----
 test/MC/COFF/cv-empty-linetable.s | 82 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 89 insertions(+), 7 deletions(-)
 create mode 100644 test/MC/COFF/cv-empty-linetable.s

diff --git a/include/llvm/MC/MCCodeView.h b/include/llvm/MC/MCCodeView.h
index 8ecdd055d12..713c3b5af5c 100644
--- a/include/llvm/MC/MCCodeView.h
+++ b/include/llvm/MC/MCCodeView.h
@@ -125,14 +125,14 @@ public:
   }
 
   std::vector<MCCVLineEntry> getFunctionLineEntries(unsigned FuncId) {
-    auto I = MCCVLineStartStop.find(FuncId);
-    assert(I != MCCVLineStartStop.end());
-
     std::vector<MCCVLineEntry> FilteredLines;
-    for (size_t Idx = I->second.first, End = I->second.second + 1; Idx != End;
-         ++Idx)
-      if (MCCVLines[Idx].getFunctionId() == FuncId)
-        FilteredLines.push_back(MCCVLines[Idx]);
+
+    auto I = MCCVLineStartStop.find(FuncId);
+    if (I != MCCVLineStartStop.end())
+      for (size_t Idx = I->second.first, End = I->second.second + 1; Idx != End;
+           ++Idx)
+        if (MCCVLines[Idx].getFunctionId() == FuncId)
+          FilteredLines.push_back(MCCVLines[Idx]);
     return FilteredLines;
   }
 
diff --git a/test/MC/COFF/cv-empty-linetable.s b/test/MC/COFF/cv-empty-linetable.s
new file mode 100644
index 00000000000..4fcafd2d268
--- /dev/null
+++ b/test/MC/COFF/cv-empty-linetable.s
@@ -0,0 +1,82 @@
+# RUN: llvm-mc -filetype=obj -triple i686-pc-win32 < %s | llvm-readobj -codeview - | FileCheck %s
+	.text
+	.def	 @feat.00;
+	.scl	3;
+	.type	0;
+	.endef
+	.globl	@feat.00
+@feat.00 = 1
+	.def	 _f;
+	.scl	2;
+	.type	32;
+	.endef
+	.globl	_f
+	.p2align	4, 0x90
+_f:                                     # @f
+Lfunc_begin0:
+# BB#0:                                 # %entry
+	.cv_file	1 "cv-empty-linetable.s"
+	.cv_loc	1 1 3 15 is_stmt 0
+	jmp	_g                      # TAILCALL
+Lfunc_end0:
+
+	.section	.debug$T,"dr"
+	.long	4
+	.short	6
+	.short	4609
+	.long	0
+	.short	14
+	.short	4104
+	.asciz	"\003\000\000\000\000\000\000\000\000\020\000"
+	.short	14
+	.short	5633
+	.asciz	"\000\000\000\000\001\020\000"
+	.ascii	"fn1"
+	.byte	0
+	.short	38
+	.short	5633
+	.asciz	"\000\000\000\000\001\020\000"
+	.ascii	"??__Fa@?1??fn1@@YAXXZ@YAXXZ"
+	.byte	0
+	.short	26
+	.short	5633
+	.asciz	"\000\000\000\000\001\020\000"
+	.ascii	"vector::~vector"
+	.byte	0
+	.section	.debug$S,"dr"
+	.long	4
+	.long	241                     # Symbol subsection for f
+	.long	Ltmp1-Ltmp0
+Ltmp0:
+	.short	Ltmp3-Ltmp2
+Ltmp2:
+	.short	4423
+	.zero	12
+	.long	Lfunc_end0-_f
+	.zero	12
+	.secrel32	_f
+	.secidx	_f
+	.byte	0
+	.byte	102
+	.byte	0
+Ltmp3:
+	.short	Ltmp5-Ltmp4
+Ltmp4:
+	.short	4429
+	.asciz	"\000\000\000\000\000\000\000\000\004\020\000"
+Ltmp5:
+	.short	2
+	.short	4430
+	.short	2
+	.short	4431
+Ltmp1:
+	.zero	3
+	.cv_linetable	0, _f, Lfunc_end0
+	.cv_filechecksums               # File index to string table offset subsection
+	.cv_stringtable                 # String table
+
+# CHECK:  FunctionLineTable [
+# CHECK:    LinkageName: _f
+# CHECK:    Flags: 0x0
+# CHECK:    CodeSize: 0x5
+# CHECK:  ]
-- 
2.11.0