[llvm-commits] [llvm] r149442 - in /llvm/trunk: lib/MC/MCObjectWriter.cpp test/MC/MachO/darwin-x86_64-diff-reloc-assign.s

[Kevin Enderby]

Author: enderby
Date: Tue Jan 31 17:02:57 2012
New Revision: 149442

URL: http://llvm.org/viewvc/llvm-project?rev=149442&view=rev
Log:
Fixed a crash in llvm-mc for Mach-O when a symbol difference expression uses a
symbol from an assignment.  In this case the symbol did not have a fragment so
MCObjectWriter::IsSymbolRefDifferenceFullyResolved() should not have been
calling IsSymbolRefDifferenceFullyResolvedImpl() with a NULL fragment and should
just have returned false in that case.

Added:
    llvm/trunk/test/MC/MachO/darwin-x86_64-diff-reloc-assign.s
Modified:
    llvm/trunk/lib/MC/MCObjectWriter.cpp

Modified: llvm/trunk/lib/MC/MCObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCObjectWriter.cpp?rev=149442&r1=149441&r2=149442&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/MCObjectWriter.cpp Tue Jan 31 17:02:57 2012
@@ -68,6 +68,8 @@
 
   const MCSymbolData &DataA = Asm.getSymbolData(SA);
   const MCSymbolData &DataB = Asm.getSymbolData(SB);
+  if(!DataA.getFragment() || !DataB.getFragment())
+    return false;
 
   return IsSymbolRefDifferenceFullyResolvedImpl(Asm, DataA,
                                                 *DataB.getFragment(),

Added: llvm/trunk/test/MC/MachO/darwin-x86_64-diff-reloc-assign.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/MachO/darwin-x86_64-diff-reloc-assign.s?rev=149442&view=auto
==============================================================================
--- llvm/trunk/test/MC/MachO/darwin-x86_64-diff-reloc-assign.s (added)
+++ llvm/trunk/test/MC/MachO/darwin-x86_64-diff-reloc-assign.s Tue Jan 31 17:02:57 2012
@@ -0,0 +1,27 @@
+// RUN: llvm-mc -triple x86_64-apple-darwin9 %s -filetype=obj -o - | macho-dump --dump-section-data | FileCheck %s
+
+// Test case for rdar://10743265
+
+// This tests that this expression does not cause a crash and produces two
+// relocation entries:
+// Relocation information (__TEXT,__text) 2 entries
+// address  pcrel length extern type    scattered symbolnum/value
+// 00000000 False long   True   SUB     False     _base
+// 00000000 False long   True   UNSIGND False     _start_ap_2
+
+_base = .
+
+.long (0x2000) + _start_ap_2 - _base 
+.word 0
+
+_start_ap_2:
+        cli
+
+// CHECK:   ('_relocations', [
+// CHECK:     # Relocation 0
+// CHECK:     (('word-0', 0x0),
+// CHECK:      ('word-1', 0x5c000000)),
+// CHECK:     # Relocation 1
+// CHECK:     (('word-0', 0x0),
+// CHECK:      ('word-1', 0xc000001)),
+// CHECK:   ])