[llvm] r264316 - [debuginfo] Include dwo_name in the split unit to improve dwp diagnostics

[David Blaikie via llvm-commits]

Author: dblaikie
Date: Thu Mar 24 13:37:08 2016
New Revision: 264316

URL: http://llvm.org/viewvc/llvm-project?rev=264316&view=rev
Log:
[debuginfo] Include dwo_name in the split unit to improve dwp diagnostics

When multiple DWP files are merged together and duplicate DWO IDs are
found it's currently difficult to give an actionable error message - the
DW_AT_name of the CU could be provided, but might be identical (if the
same source file is built into two different configurations), which
doesn't help the user identify the problem.

When no intermediate DWP files are generated, the path to the two DWO
files could be provided - but is lost once the DWOs are merged into a
DWP.

So, include the name of the DWO (dwo_name) in the split file so that
collissions involving a source CU from a DWP can be better diagnosed.

(improvements to llvm-dwp using this to come shortly)

Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
    llvm/trunk/test/DebugInfo/X86/fission-cu.ll

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=264316&r1=264315&r2=264316&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Thu Mar 24 13:37:08 2016
@@ -391,8 +391,11 @@ DwarfDebug::constructDwarfCompileUnit(co
   DwarfCompileUnit &NewCU = *OwnedUnit;
   DIE &Die = NewCU.getUnitDie();
   InfoHolder.addUnit(std::move(OwnedUnit));
-  if (useSplitDwarf())
+  if (useSplitDwarf()) {
     NewCU.setSkeleton(constructSkeletonCU(NewCU));
+    NewCU.addString(Die, dwarf::DW_AT_GNU_dwo_name,
+                    DIUnit->getSplitDebugFilename());
+  }
 
   // LTO with assembly output shares a single line table amongst multiple CUs.
   // To avoid the compilation directory being ambiguous, let the line table

Modified: llvm/trunk/test/DebugInfo/X86/fission-cu.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/fission-cu.ll?rev=264316&r1=264315&r2=264316&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/fission-cu.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/fission-cu.ll Thu Mar 24 13:37:08 2016
@@ -33,6 +33,7 @@
 ; CHECK: .debug_abbrev.dwo contents:
 ; CHECK: Abbrev table for offset: 0x00000000
 ; CHECK: [1] DW_TAG_compile_unit DW_CHILDREN_yes
+; CHECK: DW_AT_GNU_dwo_name  DW_FORM_GNU_str_index
 ; CHECK: DW_AT_producer  DW_FORM_GNU_str_index
 ; CHECK: DW_AT_language  DW_FORM_data2
 ; CHECK: DW_AT_name      DW_FORM_GNU_str_index
@@ -64,38 +65,41 @@
 ; Check that the rest of the compile units have information.
 ; CHECK: .debug_info.dwo contents:
 ; CHECK: DW_TAG_compile_unit
-; CHECK: DW_AT_producer [DW_FORM_GNU_str_index] ( indexed (00000000) string = "clang version 3.3 (trunk 169021) (llvm/trunk 169020)")
+; CHECK: DW_AT_GNU_dwo_name [DW_FORM_GNU_str_index] ( indexed (00000000) string = "baz.dwo")
+; CHECK: DW_AT_producer [DW_FORM_GNU_str_index] ( indexed (00000001) string = "clang version 3.3 (trunk 169021) (llvm/trunk 169020)")
 ; CHECK: DW_AT_language [DW_FORM_data2]        (DW_LANG_C99)
-; CHECK: DW_AT_name [DW_FORM_GNU_str_index]    ( indexed (00000001) string = "baz.c")
+; CHECK: DW_AT_name [DW_FORM_GNU_str_index]    ( indexed (00000002) string = "baz.c")
 ; CHECK-NOT: DW_AT_low_pc
 ; CHECK-NOT: DW_AT_stmt_list
 ; CHECK-NOT: DW_AT_comp_dir
 ; CHECK: DW_AT_GNU_dwo_id [DW_FORM_data8]  (0x1f1f859683d49324)
 ; CHECK: DW_TAG_variable
-; CHECK: DW_AT_name [DW_FORM_GNU_str_index]     ( indexed (00000002) string = "a")
+; CHECK: DW_AT_name [DW_FORM_GNU_str_index]     ( indexed (00000003) string = "a")
 ; CHECK: DW_AT_type [DW_FORM_ref4]       (cu + 0x{{[0-9a-f]*}} => {[[TYPE:0x[0-9a-f]*]]})
 ; CHECK: DW_AT_external [DW_FORM_flag_present]   (true)
 ; CHECK: DW_AT_decl_file [DW_FORM_data1] (0x01)
 ; CHECK: DW_AT_decl_line [DW_FORM_data1] (1)
 ; CHECK: DW_AT_location [DW_FORM_exprloc] (<0x2> fb 00 )
 ; CHECK: [[TYPE]]: DW_TAG_base_type
-; CHECK: DW_AT_name [DW_FORM_GNU_str_index]     ( indexed (00000003) string = "int")
+; CHECK: DW_AT_name [DW_FORM_GNU_str_index]     ( indexed (00000004) string = "int")
 
 ; CHECK: .debug_str contents:
 ; CHECK: 0x00000000: "baz.dwo"
 ; CHECK: 0x00000008: "/usr/local/google/home/echristo/tmp"
 
 ; CHECK: .debug_str.dwo contents:
-; CHECK: 0x00000000: "clang version 3.3 (trunk 169021) (llvm/trunk 169020)"
-; CHECK: 0x00000035: "baz.c"
-; CHECK: 0x0000003b: "a"
-; CHECK: 0x0000003d: "int"
+; CHECK: 0x00000000: "baz.dwo"
+; CHECK: 0x00000008: "clang version 3.3 (trunk 169021) (llvm/trunk 169020)"
+; CHECK: 0x0000003d: "baz.c"
+; CHECK: 0x00000043: "a"
+; CHECK: 0x00000045: "int"
 
 ; CHECK: .debug_str_offsets.dwo contents:
 ; CHECK: 0x00000000: 00000000
-; CHECK: 0x00000004: 00000035
-; CHECK: 0x00000008: 0000003b
-; CHECK: 0x0000000c: 0000003d
+; CHECK: 0x00000004: 00000008
+; CHECK: 0x00000008: 0000003d
+; CHECK: 0x0000000c: 00000043
+; CHECK: 0x00000010: 00000045
 
 ; Object file checks
 ; For x86-64-linux we should have this set of relocations for the debug info section