[llvm] r204702 - DebugInfo: Add GNU_addr_base and GNU_ranges_base only when there are addresses or ranges

[David Blaikie]

Author: dblaikie
Date: Tue Mar 25 00:34:24 2014
New Revision: 204702

URL: http://llvm.org/viewvc/llvm-project?rev=204702&view=rev
Log:
DebugInfo: Add GNU_addr_base and GNU_ranges_base only when there are addresses or ranges

Based on code review feedback from Eric in r204672.

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

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=204702&r1=204701&r2=204702&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Tue Mar 25 00:34:24 2014
@@ -956,6 +956,17 @@ void DwarfDebug::finalizeModuleInfo() {
                       dwarf::DW_FORM_data8, ID);
         SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
                       dwarf::DW_FORM_data8, ID);
+
+        // We don't keep track of which addresses are used in which CU so this
+        // is a bit pessimistic under LTO.
+        if (!InfoHolder.getAddrPool()->empty())
+          addSectionLabel(Asm, SkCU, SkCU->getUnitDie(),
+                          dwarf::DW_AT_GNU_addr_base, DwarfAddrSectionSym,
+                          DwarfAddrSectionSym);
+        if (!TheU->getRangeLists().empty())
+          addSectionLabel(Asm, SkCU, SkCU->getUnitDie(),
+                          dwarf::DW_AT_GNU_ranges_base,
+                          DwarfDebugRangeSectionSym, DwarfDebugRangeSectionSym);
       }
 
       // If we have code split among multiple sections or non-contiguous
@@ -2660,19 +2671,6 @@ DwarfCompileUnit *DwarfDebug::constructS
 
   initSkeletonUnit(CU, Die, NewCU);
 
-  // Relocate to the beginning of the addr_base section, else 0 for the
-  // beginning of the one for this compile unit.
-  // We could shave off some space if we deferred adding these attributes until
-  // the end of the CU to see if we have a non-empty debug_addr and debug_ranges
-  // sections so we don't bother with extra attributes and relocations.
-  if (Asm->MAI->doesDwarfUseRelocationsAcrossSections()) {
-    NewCU->addSectionLabel(Die, dwarf::DW_AT_GNU_addr_base, DwarfAddrSectionSym);
-    NewCU->addSectionLabel(Die, dwarf::DW_AT_GNU_ranges_base, DwarfDebugRangeSectionSym);
-  } else {
-    NewCU->addSectionOffset(Die, dwarf::DW_AT_GNU_addr_base, 0);
-    NewCU->addSectionOffset(Die, dwarf::DW_AT_GNU_ranges_base, 0);
-  }
-
   return NewCU;
 }
 

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=204702&r1=204701&r2=204702&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/fission-cu.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/fission-cu.ll Tue Mar 25 00:34:24 2014
@@ -59,8 +59,6 @@
 ; CHECK-NEXT: DW_AT_stmt_list [DW_FORM_sec_offset]   (0x00000000)
 ; CHECK-NEXT: DW_AT_GNU_dwo_name [DW_FORM_strp] ( .debug_str[0x00000000] = "baz.dwo")
 ; CHECK-NEXT: DW_AT_comp_dir [DW_FORM_strp]     ( .debug_str[0x00000008] = "/usr/local/google/home/echristo/tmp")
-; CHECK-NEXT: DW_AT_GNU_addr_base [DW_FORM_sec_offset]                   (0x00000000)
-; CHECK-NEXT: DW_AT_GNU_ranges_base [DW_FORM_sec_offset]                   (0x00000000)
 ; CHECK-NEXT: DW_AT_GNU_dwo_id [DW_FORM_data8]  (0x1f1f859683d49324)
 
 ; Check that the rest of the compile units have information.
@@ -108,7 +106,6 @@
 ; OBJ-NEXT: R_X86_64_32 .debug_str
 ; OBJ-NEXT: R_X86_64_32 .debug_str
 ; OBJ-NEXT: R_X86_64_32 .debug_addr
-; OBJ-NEXT: R_X86_64_32 .debug_ranges
 ; OBJ-NEXT: }
 
 ; HDR-NOT: .debug_aranges

Modified: llvm/trunk/test/DebugInfo/X86/fission-ranges.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/fission-ranges.ll?rev=204702&r1=204701&r2=204702&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/fission-ranges.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/fission-ranges.ll Tue Mar 25 00:34:24 2014
@@ -2,6 +2,15 @@
 ; RUN: llvm-dwarfdump %t | FileCheck %s
 ; RUN: llvm-objdump -h %t | FileCheck --check-prefix=HDR %s
 
+; CHECK: .debug_info contents:
+; CHECK: DW_TAG_compile_unit
+; CHECK-NEXT: DW_AT_stmt_list
+; CHECK-NEXT: DW_AT_GNU_dwo_name
+; CHECK-NEXT: DW_AT_comp_dir
+; CHECK-NEXT: DW_AT_GNU_dwo_id
+; CHECK-NEXT: DW_AT_GNU_addr_base [DW_FORM_sec_offset]                   (0x00000000)
+
+
 ; CHECK: .debug_info.dwo contents:
 ; CHECK: DW_AT_location [DW_FORM_sec_offset]   ([[A:0x[0-9a-z]*]])
 ; CHECK: DW_AT_location [DW_FORM_sec_offset]   ([[E:0x[0-9a-z]*]])

Modified: llvm/trunk/test/DebugInfo/empty.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/empty.ll?rev=204702&r1=204701&r2=204702&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/empty.ll (original)
+++ llvm/trunk/test/DebugInfo/empty.ll Tue Mar 25 00:34:24 2014
@@ -1,6 +1,7 @@
 ; REQUIRES: object-emission
 
 ; RUN: %llc_dwarf < %s -filetype=obj | llvm-dwarfdump - | FileCheck %s
+; RUN: %llc_dwarf -split-dwarf=Enable < %s -filetype=obj | llvm-dwarfdump - | FileCheck --check-prefix=FISSION %s
 
 ; darwin has a workaround for a linker bug so it always emits one line table entry
 ; XFAIL: darwin
@@ -17,6 +18,9 @@
 ; CHECK: .debug_pubtypes contents:
 ; CHECK-NOT: Offset
 
+; Don't emit DW_AT_addr_base when there are no addresses.
+; FISSION-NOT: DW_AT_GNU_addr_base [DW_FORM_sec_offset]
+
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!5}