[llvm-commits] [llvm] r151655 - in /llvm/trunk: include/llvm/MC/MCDwarf.h lib/MC/MCAsmStreamer.cpp lib/MC/MCDwarf.cpp lib/MC/MCObjectStreamer.cpp test/MC/ELF/gen-dwarf.s
Rafael Espindola
rafael.espindola at gmail.com
Tue Feb 28 13:13:05 PST 2012
Author: rafael
Date: Tue Feb 28 15:13:05 2012
New Revision: 151655
URL: http://llvm.org/viewvc/llvm-project?rev=151655&view=rev
Log:
On ELF, create relocations to the abbreviation and line sections when producing
debug info for assembly files. We were already doing the right thing when
producing debug info for C/C++.
ELF linkers don't know dwarf, so they depend on these relocations to produce
valid dwarf output.
Added:
llvm/trunk/test/MC/ELF/gen-dwarf.s
Modified:
llvm/trunk/include/llvm/MC/MCDwarf.h
llvm/trunk/lib/MC/MCAsmStreamer.cpp
llvm/trunk/lib/MC/MCDwarf.cpp
llvm/trunk/lib/MC/MCObjectStreamer.cpp
Modified: llvm/trunk/include/llvm/MC/MCDwarf.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCDwarf.h?rev=151655&r1=151654&r2=151655&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCDwarf.h (original)
+++ llvm/trunk/include/llvm/MC/MCDwarf.h Tue Feb 28 15:13:05 2012
@@ -212,7 +212,7 @@
//
// This emits the Dwarf file and the line tables.
//
- static void Emit(MCStreamer *MCOS);
+ static const MCSymbol *Emit(MCStreamer *MCOS);
};
class MCDwarfLineAddr {
@@ -235,7 +235,7 @@
// When generating dwarf for assembly source files this emits the Dwarf
// sections.
//
- static void Emit(MCStreamer *MCOS);
+ static void Emit(MCStreamer *MCOS, const MCSymbol *LineSectionSymbol);
};
// When generating dwarf for assembly source files this is the info that is
Modified: llvm/trunk/lib/MC/MCAsmStreamer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCAsmStreamer.cpp?rev=151655&r1=151654&r2=151655&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCAsmStreamer.cpp (original)
+++ llvm/trunk/lib/MC/MCAsmStreamer.cpp Tue Feb 28 15:13:05 2012
@@ -1309,13 +1309,15 @@
}
void MCAsmStreamer::FinishImpl() {
+ // FIXME: This header is duplicated with MCObjectStreamer
// Dump out the dwarf file & directory tables and line tables.
+ const MCSymbol *LineSectionSymbol;
if (getContext().hasDwarfFiles() && !UseLoc)
- MCDwarfFileTable::Emit(this);
+ LineSectionSymbol = MCDwarfFileTable::Emit(this);
// If we are generating dwarf for assembly source files dump out the sections.
if (getContext().getGenDwarfForAssembly())
- MCGenDwarfInfo::Emit(this);
+ MCGenDwarfInfo::Emit(this, LineSectionSymbol);
if (!UseCFI)
EmitFrames(false);
Modified: llvm/trunk/lib/MC/MCDwarf.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCDwarf.cpp?rev=151655&r1=151654&r2=151655&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCDwarf.cpp (original)
+++ llvm/trunk/lib/MC/MCDwarf.cpp Tue Feb 28 15:13:05 2012
@@ -209,7 +209,7 @@
//
// This emits the Dwarf file and the line tables.
//
-void MCDwarfFileTable::Emit(MCStreamer *MCOS) {
+const MCSymbol *MCDwarfFileTable::Emit(MCStreamer *MCOS) {
MCContext &context = MCOS->getContext();
// Switch to the section where the table will be emitted into.
MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
@@ -322,6 +322,8 @@
// This is the end of the section, so set the value of the symbol at the end
// of this section (that was used in a previous expression).
MCOS->EmitLabel(LineEndSym);
+
+ return LineStartSym;
}
/// Utility function to write the encoding to an object writer.
@@ -545,7 +547,9 @@
// When generating dwarf for assembly source files this emits the data for
// .debug_info section which contains three parts. The header, the compile_unit
// DIE and a list of label DIEs.
-static void EmitGenDwarfInfo(MCStreamer *MCOS) {
+static void EmitGenDwarfInfo(MCStreamer *MCOS,
+ const MCSymbol *AbbrevSectionSymbol,
+ const MCSymbol *LineSectionSymbol) {
MCContext &context = MCOS->getContext();
MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
@@ -568,7 +572,11 @@
// The 4 byte offset to the debug abbrevs from the start of the .debug_abbrev,
// it is at the start of that section so this is zero.
- MCOS->EmitIntValue(0, 4);
+ if (AbbrevSectionSymbol) {
+ MCOS->EmitSymbolValue(AbbrevSectionSymbol, 4);
+ } else {
+ MCOS->EmitIntValue(0, 4);
+ }
const MCAsmInfo &asmInfo = context.getAsmInfo();
int AddrSize = asmInfo.getPointerSize();
@@ -582,7 +590,11 @@
// DW_AT_stmt_list, a 4 byte offset from the start of the .debug_line section,
// which is at the start of that section so this is zero.
- MCOS->EmitIntValue(0, 4);
+ if (LineSectionSymbol) {
+ MCOS->EmitSymbolValue(LineSectionSymbol, 4);
+ } else {
+ MCOS->EmitIntValue(0, 4);
+ }
// AT_low_pc, the first address of the default .text section.
const MCExpr *Start = MCSymbolRefExpr::Create(
@@ -686,11 +698,20 @@
// When generating dwarf for assembly source files this emits the Dwarf
// sections.
//
-void MCGenDwarfInfo::Emit(MCStreamer *MCOS) {
+void MCGenDwarfInfo::Emit(MCStreamer *MCOS, const MCSymbol *LineSectionSymbol) {
// Create the dwarf sections in this order (.debug_line already created).
MCContext &context = MCOS->getContext();
+ const MCAsmInfo &AsmInfo = context.getAsmInfo();
MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
+ MCSymbol *AbbrevSectionSymbol;
+ if (AsmInfo.doesDwarfRequireRelocationForSectionOffset()) {
+ AbbrevSectionSymbol = context.CreateTempSymbol();
+ MCOS->EmitLabel(AbbrevSectionSymbol);
+ } else {
+ AbbrevSectionSymbol = NULL;
+ LineSectionSymbol = NULL;
+ }
MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
// If there are no line table entries then do not emit any section contents.
@@ -704,7 +725,7 @@
EmitGenDwarfAbbrev(MCOS);
// Output the data for .debug_info section.
- EmitGenDwarfInfo(MCOS);
+ EmitGenDwarfInfo(MCOS, AbbrevSectionSymbol, LineSectionSymbol);
}
//
Modified: llvm/trunk/lib/MC/MCObjectStreamer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCObjectStreamer.cpp?rev=151655&r1=151654&r2=151655&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCObjectStreamer.cpp (original)
+++ llvm/trunk/lib/MC/MCObjectStreamer.cpp Tue Feb 28 15:13:05 2012
@@ -266,12 +266,13 @@
void MCObjectStreamer::FinishImpl() {
// Dump out the dwarf file & directory tables and line tables.
+ const MCSymbol *LineSectionSymbol;
if (getContext().hasDwarfFiles())
- MCDwarfFileTable::Emit(this);
+ LineSectionSymbol = MCDwarfFileTable::Emit(this);
// If we are generating dwarf for assembly source files dump out the sections.
if (getContext().getGenDwarfForAssembly())
- MCGenDwarfInfo::Emit(this);
+ MCGenDwarfInfo::Emit(this, LineSectionSymbol);
getAssembler().Finish();
}
Added: llvm/trunk/test/MC/ELF/gen-dwarf.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ELF/gen-dwarf.s?rev=151655&view=auto
==============================================================================
--- llvm/trunk/test/MC/ELF/gen-dwarf.s (added)
+++ llvm/trunk/test/MC/ELF/gen-dwarf.s Tue Feb 28 15:13:05 2012
@@ -0,0 +1,70 @@
+// RUN: llvm-mc -g -triple i686-pc-linux-gnu %s -filetype=obj -o - | elf-dump | FileCheck %s
+
+
+// Test that on ELF the debug info has a relocation to debug_abbrev and one to
+// to debug_line.
+
+
+ .text
+ .globl foo
+ .type foo, @function
+ .align 4
+foo:
+ ret
+ .size foo, .-foo
+
+// Section 4 is .debug_line
+// CHECK: # Section 4
+// CHECK-NEXT: # '.debug_line'
+
+
+
+// The two relocations, one to symbol 6 and one to 4
+// CHECK: # '.rel.debug_info'
+// CHECK-NEXT: ('sh_type',
+// CHECK-NEXT: ('sh_flags'
+// CHECK-NEXT: ('sh_addr',
+// CHECK-NEXT: ('sh_offset',
+// CHECK-NEXT: ('sh_size',
+// CHECK-NEXT: ('sh_link',
+// CHECK-NEXT: ('sh_info',
+// CHECK-NEXT: ('sh_addralign',
+// CHECK-NEXT: ('sh_entsize',
+// CHECK-NEXT: ('_relocations', [
+// CHECK-NEXT: # Relocation 0
+// CHECK-NEXT: (('r_offset', 0x00000006)
+// CHECK-NEXT: ('r_sym', 0x000006)
+// CHECK-NEXT: ('r_type', 0x01)
+// CHECK-NEXT: ),
+// CHECK-NEXT: # Relocation 1
+// CHECK-NEXT: (('r_offset', 0x0000000c)
+// CHECK-NEXT: ('r_sym', 0x000004)
+// CHECK-NEXT: ('r_type', 0x01)
+// CHECK-NEXT: ),
+
+
+// Section 8 is .debug_abbrev
+// CHECK: # Section 8
+// CHECK-NEXT: (('sh_name', 0x00000001) # '.debug_abbrev'
+
+// Symbol 4 is section 4 (.debug_line)
+// CHECK: # Symbol 4
+// CHECK-NEXT: (('st_name', 0x00000000) # ''
+// CHECK-NEXT: ('st_value', 0x00000000)
+// CHECK-NEXT: ('st_size', 0x00000000)
+// CHECK-NEXT: ('st_bind', 0x0)
+// CHECK-NEXT: ('st_type', 0x3)
+// CHECK-NEXT: ('st_other', 0x00)
+// CHECK-NEXT: ('st_shndx', 0x0004)
+// CHECK-NEXT: ),
+
+// Symbol 6 is section 8 (.debug_abbrev)
+// CHECK: # Symbol 6
+// CHECK-NEXT: (('st_name', 0x00000000) # ''
+// CHECK-NEXT: ('st_value', 0x00000000)
+// CHECK-NEXT: ('st_size', 0x00000000)
+// CHECK-NEXT: ('st_bind', 0x0)
+// CHECK-NEXT: ('st_type', 0x3)
+// CHECK-NEXT: ('st_other', 0x00)
+// CHECK-NEXT: ('st_shndx', 0x0008)
+// CHECK-NEXT: ),
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