DW_FORM_sec_offset should be a relocation on platforms that use

a relocation across sections. Do this for DW_AT_stmt list in the
skeleton CU and check the relocations in the debug_info section.

Add a FIXME for multiple CUs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178969 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 35 insertions, 7 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 8bd9feb92a..75ebcff196 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -170,6 +170,7 @@ DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
   DwarfInfoSectionSym = DwarfAbbrevSectionSym = 0;
   DwarfStrSectionSym = TextSectionSym = 0;
   DwarfDebugRangeSectionSym = DwarfDebugLocSectionSym = DwarfLineSectionSym = 0;
+  DwarfAddrSectionSym = 0;
   DwarfAbbrevDWOSectionSym = DwarfStrDWOSectionSym = 0;
   FunctionBeginSym = FunctionEndSym = 0;
 
@@ -1740,9 +1741,12 @@ void DwarfDebug::emitSectionLabels() {
   emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
   DwarfStrSectionSym =
     emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
-  if (useSplitDwarf())
+  if (useSplitDwarf()) {
     DwarfStrDWOSectionSym =
       emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
+    DwarfAddrSectionSym =
+      emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
+  }
   DwarfDebugRangeSectionSym = emitSectionSym(Asm, TLOF.getDwarfRangesSection(),
                                              "debug_range");
 
@@ -2510,9 +2514,13 @@ CompileUnit *DwarfDebug::constructSkeletonCU(const MDNode *N) {
   // This should be a unique identifier when we want to build .dwp files.
   NewCU->addUInt(Die, dwarf::DW_AT_GNU_dwo_id, dwarf::DW_FORM_data8, 0);
 
-  // FIXME: The addr base should be relative for each compile unit, however,
-  // this one is going to be 0 anyhow.
-  NewCU->addUInt(Die, dwarf::DW_AT_GNU_addr_base, dwarf::DW_FORM_sec_offset, 0);
+  // Relocate to the beginning of the addr_base section, else 0 for the beginning
+  // of the one for this compile unit.
+  if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
+    NewCU->addLabel(Die, dwarf::DW_AT_GNU_addr_base, dwarf::DW_FORM_sec_offset,
+                    DwarfAddrSectionSym);
+  else
+    NewCU->addUInt(Die, dwarf::DW_AT_GNU_addr_base, dwarf::DW_FORM_sec_offset, 0);
 
   // 2.17.1 requires that we use DW_AT_low_pc for a single entry point
   // into an entity. We're using 0, or a NULL label for this.
@@ -2520,6 +2528,7 @@ CompileUnit *DwarfDebug::constructSkeletonCU(const MDNode *N) {
 
   // DW_AT_stmt_list is a offset of line number information for this
   // compile unit in debug_line section.
+  // FIXME: Should handle multiple compile units.
   if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
     NewCU->addLabel(Die, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_sec_offset,
                     DwarfLineSectionSym);
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 81e345e628..9a38256d8e 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -392,7 +392,7 @@ class DwarfDebug {
   // section offsets and are created by EmitSectionLabels.
   MCSymbol *DwarfInfoSectionSym, *DwarfAbbrevSectionSym;
   MCSymbol *DwarfStrSectionSym, *TextSectionSym, *DwarfDebugRangeSectionSym;
-  MCSymbol *DwarfDebugLocSectionSym, *DwarfLineSectionSym;
+  MCSymbol *DwarfDebugLocSectionSym, *DwarfLineSectionSym, *DwarfAddrSectionSym;
   MCSymbol *FunctionBeginSym, *FunctionEndSym;
   MCSymbol *DwarfAbbrevDWOSectionSym, *DwarfStrDWOSectionSym;
 
diff --git a/lib/DebugInfo/DWARFFormValue.cpp b/lib/DebugInfo/DWARFFormValue.cpp
index 9f807aac5f..d29af3595f 100644
--- a/lib/DebugInfo/DWARFFormValue.cpp
+++ b/lib/DebugInfo/DWARFFormValue.cpp
@@ -172,10 +172,17 @@ DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
       Form = data.getULEB128(offset_ptr);
       indirect = true;
       break;
-    case DW_FORM_sec_offset:
+    case DW_FORM_sec_offset: {
       // FIXME: This is 64-bit for DWARF64.
-      Value.uval = data.getU32(offset_ptr);
+      RelocAddrMap::const_iterator AI
+        = cu->getRelocMap()->find(*offset_ptr);
+      if (AI != cu->getRelocMap()->end()) {
+        const std::pair<uint8_t, int64_t> &R = AI->second;
+        Value.uval = data.getU32(offset_ptr) + R.second;
+      } else
+        Value.uval = data.getU32(offset_ptr);
       break;
+    }
     case DW_FORM_flag_present:
       Value.uval = 1;
       break;
diff --git a/test/DebugInfo/X86/fission-cu.ll b/test/DebugInfo/X86/fission-cu.ll
index bfe2d17e20..e139e3be77 100644
--- a/test/DebugInfo/X86/fission-cu.ll
+++ b/test/DebugInfo/X86/fission-cu.ll
@@ -1,5 +1,6 @@
 ; RUN: llc -split-dwarf=Enable -O0 %s -mtriple=x86_64-unknown-linux-gnu -filetype=obj -o %t
 ; RUN: llvm-dwarfdump -debug-dump=all %t | FileCheck %s
+; RUN: llvm-readobj --relocations %t | FileCheck --check-prefix=OBJ %s
 
 @a = common global i32 0, align 4
 
@@ -98,3 +99,14 @@
 ; CHECK: 0x00000008: 0000003b
 ; CHECK: 0x0000000c: 0000005f
 ; CHECK: 0x00000010: 00000061
+
+; Object file checks
+; For x86-64-linux we should have this set of relocations for the debug info section
+;
+; OBJ: .debug_info
+; OBJ-NEXT: R_X86_64_32 .debug_abbrev
+; OBJ-NEXT: R_X86_64_32 .debug_str
+; OBJ-NEXT: R_X86_64_32 .debug_addr
+; OBJ-NEXT: R_X86_64_32 .debug_line
+; OBJ-NEXT: R_X86_64_32 .debug_str
+; OBJ-NEXT: }