DebugInfo: Emit DW_TAG_subprogram's DW_AT_high_pc as an offset from the low_pc

This removes a relocation from each subprogram, reducing link times,
etc.

llvm-svn: 203187

3 files changed, 12 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index d30be282361..7abd2f1dc73 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -413,7 +413,8 @@ DIE *DwarfDebug::updateSubprogramScopeDIE(DwarfCompileUnit *SPCU,
   }
 
   SPCU->addLabelAddress(SPDie, dwarf::DW_AT_low_pc, FunctionBeginSym);
-  SPCU->addLabelAddress(SPDie, dwarf::DW_AT_high_pc, FunctionEndSym);
+  SPCU->addLabelDelta(SPDie, dwarf::DW_AT_high_pc, FunctionEndSym,
+                      FunctionBeginSym);
 
   const TargetRegisterInfo *RI = Asm->TM.getRegisterInfo();
   MachineLocation Location(RI->getFrameRegister(*Asm->MF));
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index ddc1c2f4bc0..e046bf417b6 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -320,6 +320,12 @@ void DwarfUnit::addSectionDelta(DIE *Die, dwarf::Attribute Attribute,
     Die->addValue(Attribute, dwarf::DW_FORM_data4, Value);
 }
 
+void DwarfUnit::addLabelDelta(DIE *Die, dwarf::Attribute Attribute,
+                              const MCSymbol *Hi, const MCSymbol *Lo) {
+  DIEValue *Value = new (DIEValueAllocator) DIEDelta(Hi, Lo);
+  Die->addValue(Attribute, dwarf::DW_FORM_data4, Value);
+}
+
 /// addDIEEntry - Add a DIE attribute data and value.
 ///
 void DwarfUnit::addDIEEntry(DIE *Die, dwarf::Attribute Attribute, DIE *Entry) {
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
index 937a607fa88..af465c006ed 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
@@ -359,6 +359,10 @@ public:
   void addSectionDelta(DIE *Die, dwarf::Attribute Attribute, const MCSymbol *Hi,
                        const MCSymbol *Lo);
 
+  /// addLabelDelta - Add a label delta attribute data and value.
+  void addLabelDelta(DIE *Die, dwarf::Attribute Attribute, const MCSymbol *Hi,
+                     const MCSymbol *Lo);
+
   /// addDIEEntry - Add a DIE attribute data and value.
   void addDIEEntry(DIE *Die, dwarf::Attribute Attribute, DIE *Entry);