[llvm] r201187 - DebugInfo: Don't include the name of the CU file in the line table file list when it's unneeded

[David Blaikie]

Author: dblaikie
Date: Tue Feb 11 15:49:46 2014
New Revision: 201187

URL: http://llvm.org/viewvc/llvm-project?rev=201187&view=rev
Log:
DebugInfo: Don't include the name of the CU file in the line table file list when it's unneeded

This comes up in empty files or files containing #file directives that
never reference the actual source file name. Came up in a small test of
line tables I was playing with.

Added:
    llvm/trunk/test/DebugInfo/empty.ll
Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=201187&r1=201186&r2=201187&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Tue Feb 11 15:49:46 2014
@@ -751,9 +751,6 @@ DwarfCompileUnit *DwarfDebug::constructD
   InfoHolder.addUnit(NewCU);
 
   FileIDCUMap[NewCU->getUniqueID()] = 0;
-  // Call this to emit a .file directive if it wasn't emitted for the source
-  // file this CU comes from yet.
-  getOrCreateSourceID(FN, CompilationDir, NewCU->getUniqueID());
 
   NewCU->addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
   NewCU->addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,

Added: llvm/trunk/test/DebugInfo/empty.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/empty.ll?rev=201187&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/empty.ll (added)
+++ llvm/trunk/test/DebugInfo/empty.ll Tue Feb 11 15:49:46 2014
@@ -0,0 +1,15 @@
+; RUN: llc %s -o %t -filetype=obj
+; RUN: llvm-dwarfdump -debug-dump=line %t | FileCheck %s
+
+; Expect no line table entry since there are no functions and file references in this compile unit
+; CHECK: .debug_line contents:
+; CHECK-NOT: Line table prologue:
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!5}
+
+!0 = metadata !{i32 720913, metadata !4, i32 12, metadata !"clang version 3.1 (trunk 143523)", i1 true, metadata !"", i32 0, metadata !2, metadata !2, metadata !2, metadata !2, null, metadata !""} ; [ DW_TAG_compile_unit ]
+!2 = metadata !{}
+!3 = metadata !{i32 786473, metadata !4} ; [ DW_TAG_file_type ]
+!4 = metadata !{metadata !"empty.c", metadata !"/home/nlewycky"}
+!5 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}