Emit one CodeView S_COMPILE3 record per TU rather than per function

[amccarth]

Summary

Most of the change is ripple effects in tests.

[rnk]

Looks good, mostly a bunch of comments about how to make the tests less fragile.

test/DebugInfo/COFF/asm.ll

29

I think this test is really supposed to be about the line table. I think we should keep the .cv_loc directive matching above, but delete all this .debug$S directive matching to make the test less fragile.

See the FIXME comment below and http://llvm.org/PR18679. I think that explains why this test is here.

69–74

Let's delete the relocation matching. They aren't interesting in this test.

134–137

Ditto, I don't think we need x64 .debug$S assembly matching, just line table matching below.

test/DebugInfo/COFF/multifile.ll

35

This test is also entirely concerned with what happens to the line table when you use #line inside a function. I think we can do the same here: delete the .debug$S assembly matching portion and relocation entries.

The FilenameSegment checks below are the interesting part.

test/DebugInfo/COFF/multifunction.ll

58

This is supposed to test how we emit one symbol subsection per function, so I think it's worth matching the compile info subsection.

The names F1_START and F1_END were intended to refer to the symbol subsection for x, but this is actually the compile info subection now. Let's use F1_START / F1_END in place of SUBSEC_START / SUBSEC_END and use COMPILE_START / COMPILE_END here.

146–158

I don't think the relocation entries are interesting anymore, let's delete them.

test/DebugInfo/COFF/simple.ll

28

Let's update the names to COMPILE_START/END and use F1_START/END below.

[rnk]

I was going to say, the old line table tests that Timur added when CodeView support was new (asm.ll, simple.ll, multfile.ll, and multifunction.ll in rL200340) overfit our output because we didn't have a lot of confidence in our understanding of the format.

[amccarth]

test/DebugInfo/COFF/multifunction.ll

58

Yeah, duh. I realized that mistake earlier, but promptly forgot about it.

[amccarth]

Made tests less fragile per Reid's suggestions.

[rnk]

lgtm

[amccarth]

Committed in r285862

lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

void CodeViewDebug::endModule() {
   // The COFF .debug$S section consists of several subsections, each starting
   // with a 4-byte control code (e.g. 0xF1, 0xF2, etc) and then a 4-byte length
   // of the payload followed by the payload itself.  The subsections are 4-byte
   // aligned.
 
   // Use the generic .debug$S section, and make a subsection for all the inlined
   // subprograms.
   switchToDebugSectionForSymbol(nullptr);
+
+  MCSymbol *CompilerInfo = beginCVSubsection(ModuleSubstreamKind::Symbols);
+  emitCompilerInformation();
+  endCVSubsection(CompilerInfo);
+
   emitInlineeLinesSubsection();
 
   // Emit per-function debug information.
   for (auto &P : FnDebugInfo)
     if (!P.first->isDeclarationForLinker())
       emitDebugInfoForFunction(P.first, P.second);
 
   // Emit global variable debug information.

 
 MCSymbol *CodeViewDebug::beginCVSubsection(ModuleSubstreamKind Kind) {
   MCSymbol *BeginLabel = MMI->getContext().createTempSymbol(),
            *EndLabel = MMI->getContext().createTempSymbol();
   OS.EmitIntValue(unsigned(Kind), 4);
   OS.AddComment("Subsection size");
   OS.emitAbsoluteSymbolDiff(EndLabel, BeginLabel, 4);
   OS.EmitLabel(BeginLabel);
-  if (Kind == ModuleSubstreamKind::Symbols)
-    emitCompilerInformation();
   return EndLabel;
 }
 
 void CodeViewDebug::endCVSubsection(MCSymbol *EndLabel) {
   OS.EmitLabel(EndLabel);
   // Every subsection must be aligned to a 4-byte boundary.
   OS.EmitValueToAlignment(4);
 }

test/DebugInfo/COFF/asm.ll

 ; X86:      ret
 ; X86:      [[END_OF_F:.?Lfunc_end.*]]:
 ;
 ; X86-LABEL: .section        .debug$S,"dr"
 ; X86-NEXT: .p2align 2
 ; X86-NEXT: .long   4
 ; Symbol subsection
 ; X86-NEXT: .long   241
 ; X86-NEXT: .long [[F1_END:.*]]-[[F1_START:.*]] #
 ; Compiler information record
 ; X86-NEXT: [[F1_START]]:
 ; X86-NEXT: .short [[C1_END:.*]]-[[C1_START:.*]] #
 ; X86:      [[C1_END]]:
+; X86-NEXT: [[F1_END]]:
+; X86-NEXT: .p2align  2
+; X86-NEXT: .long 241                     # Symbol subsection for f
+; X86-NEXT: .long [[SUBSEC_END:.*]]-[[SUBSEC_START:.*]] # Subsection size
+; X86-NEXT: [[SUBSEC_START]]:
 ; X86-NEXT: .short [[PROC_SEGMENT_END:.*]]-[[PROC_SEGMENT_START:.*]] #
 ; X86-NEXT: [[PROC_SEGMENT_START]]:
 ; X86-NEXT: .short  4423
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long [[END_OF_F]]-_f
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   4098
 ; X86-NEXT: .secrel32 _f
 ; X86-NEXT: .secidx _f
 ; X86-NEXT: .byte   0
 ; X86-NEXT: .asciz "f"
 ; X86-NEXT: [[PROC_SEGMENT_END]]:
 ; X86-NEXT: .short  2
 ; X86-NEXT: .short  4431
-; X86-NEXT: [[F1_END]]:
+; X86-NEXT: [[SUBSEC_END]]:
 ; X86-NEXT: .p2align 2
 ; Line table
 ; X86-NEXT: .cv_linetable 0, _f, [[END_OF_F]]
 ; File index to string table offset subsection
 ; X86-NEXT: .cv_filechecksums
 ; String table
 ; X86-NEXT: .cv_stringtable
 
 ; OBJ32:    Section {
 ; OBJ32:      Name: .debug$S (2E 64 65 62 75 67 24 53)
 ; OBJ32:      Characteristics [ (0x42300040)
 ; OBJ32:      ]
 ; OBJ32:      Relocations [
-; OBJ32-NEXT:   0x59 IMAGE_REL_I386_SECREL _f
-; OBJ32-NEXT:   0x5D IMAGE_REL_I386_SECTION _f
-; OBJ32-NEXT:   0x70 IMAGE_REL_I386_SECREL _f
-; OBJ32-NEXT:   0x74 IMAGE_REL_I386_SECTION _f
+; OBJ32-NEXT:   0x64 IMAGE_REL_I386_SECREL _f
+; OBJ32-NEXT:   0x68 IMAGE_REL_I386_SECTION _f
+; OBJ32-NEXT:   0x7C IMAGE_REL_I386_SECREL _f
+; OBJ32-NEXT:   0x80 IMAGE_REL_I386_SECTION _f
 ; OBJ32-NEXT: ]
 ; OBJ32:    CodeViewDebugInfo [
 ; OBJ32:      Subsection [
 ; OBJ32-NEXT:   SubSectionType: Symbols (0xF1)
 ; OBJ32:        ProcStart {
 ; OBJ32:          CodeSize: 0x6
 ; OBJ32:          DisplayName: f
 ; OBJ32:          LinkageName: _f
 ; OBJ32:        }

 ; X64-NEXT: .long   4
 ; Symbol subsection
 ; X64-NEXT: .long   241
 ; X64-NEXT: .long [[F1_END:.*]]-[[F1_START:.*]] #
 ; Compiler information record
 ; X64-NEXT: [[F1_START]]:
 ; X64-NEXT: .short [[C1_END:.*]]-[[C1_START:.*]] #
 ; X64:      [[C1_END]]:
+; X64-NEXT: [[F1_END]]:
+; X64-NEXT: .p2align  2
+; X64-NEXT: .long 241                     # Symbol subsection for f
+; X64-NEXT: .long [[SUBSEC_END:.*]]-[[SUBSEC_START:.*]] # Subsection size
+; X64-NEXT: [[SUBSEC_START]]:
 ; X64-NEXT: .short [[PROC_SEGMENT_END:.*]]-[[PROC_SEGMENT_START:.*]] #
 ; X64-NEXT: [[PROC_SEGMENT_START]]:
 ; X64-NEXT: .short  4423
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long [[END_OF_F]]-f
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   4098
 ; X64-NEXT: .secrel32 f
 ; X64-NEXT: .secidx f
 ; X64-NEXT: .byte   0
 ; X64-NEXT: .asciz "f"
 ; X64-NEXT: [[PROC_SEGMENT_END]]:
 ; X64-NEXT: .short  2
 ; X64-NEXT: .short  4431
-; X64-NEXT: [[F1_END]]:
+; X64-NEXT: [[SUBSEC_END]]:
 ; X64-NEXT: .p2align 2
 ; Line table
 ; X64-NEXT: .cv_linetable 0, f, [[END_OF_F]]
 ; File index to string table offset subsection
 ; X64-NEXT: .cv_filechecksums
 ; String table
 ; X64-NEXT: .cv_stringtable
 
 ; OBJ64:    Section {
 ; OBJ64:      Name: .debug$S (2E 64 65 62 75 67 24 53)
 ; OBJ64:      Characteristics [ (0x42300040)
 ; OBJ64:      ]
 ; OBJ64:      Relocations [
-; OBJ64-NEXT:   0x59 IMAGE_REL_AMD64_SECREL f
-; OBJ64-NEXT:   0x5D IMAGE_REL_AMD64_SECTION f
-; OBJ64-NEXT:   0x70 IMAGE_REL_AMD64_SECREL f
-; OBJ64-NEXT:   0x74 IMAGE_REL_AMD64_SECTION f
+; OBJ64-NEXT:   0x64 IMAGE_REL_AMD64_SECREL f
+; OBJ64-NEXT:   0x68 IMAGE_REL_AMD64_SECTION f
+; OBJ64-NEXT:   0x7C IMAGE_REL_AMD64_SECREL f
+; OBJ64-NEXT:   0x80 IMAGE_REL_AMD64_SECTION f
 ; OBJ64-NEXT: ]
 ; OBJ64:      Subsection [
 ; OBJ64-NEXT:   SubSectionType: Symbols (0xF1)
 ; OBJ64:        ProcStart {
 ; OBJ64:          CodeSize: 0xE
 ; OBJ64:          DisplayName: f
 ; OBJ64:          LinkageName: f
 ; OBJ64:        }

test/DebugInfo/COFF/multifile.ll

 ; X86:      .cv_loc 0 1 7 0 # one.c:7:0
 ; X86:      calll   _g
 ; X86:      .cv_loc 0 1 8 0 # one.c:8:0
 ; X86:      ret
 ; X86:      [[END_OF_F:.?Lfunc_end.*]]:
 ;
 ; X86-LABEL: .section        .debug$S,"dr"
 ; X86-NEXT: .p2align 2
 ; X86-NEXT: .long   4
 ; Symbol subsection
 ; X86-NEXT: .long   241
 ; X86-NEXT: .long [[F1_END:.*]]-[[F1_START:.*]] #
 ; Compiler information record
 ; X86-NEXT: [[F1_START]]:
 ; X86-NEXT: .short [[C1_END:.*]]-[[C1_START:.*]] #
 ; X86:      [[C1_END]]:
+; X86-NEXT: [[F1_END]]:
+; X86-NEXT: .p2align  2
+; X86-NEXT: .long 241                     # Symbol subsection for f
+; X86-NEXT: .long [[SUBSEC_END:.*]]-[[SUBSEC_START:.*]] # Subsection size
+; X86-NEXT: [[SUBSEC_START]]:
 ; X86-NEXT: .short [[PROC_SEGMENT_END:.*]]-[[PROC_SEGMENT_START:.*]] #
 ; X86-NEXT: [[PROC_SEGMENT_START]]:
 ; X86-NEXT: .short  4423
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long [[END_OF_F]]-_f
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   4098
 ; X86-NEXT: .secrel32 _f
 ; X86-NEXT: .secidx _f
 ; X86-NEXT: .byte   0
 ; X86-NEXT: .asciz "f"
 ; X86-NEXT: [[PROC_SEGMENT_END]]:
 ; X86-NEXT: .short  2
 ; X86-NEXT: .short  4431
-; X86-NEXT: [[F1_END]]:
+; X86-NEXT: [[SUBSEC_END]]:
 ; X86-NEXT: .p2align   2
 ; Line table
 ; X86-NEXT: .cv_linetable 0, _f, [[END_OF_F]]
 ; File index to string table offset subsection
 ; X86-NEXT: .cv_filechecksums
 ; String table
 ; X86-NEXT: .cv_stringtable
 
 ; OBJ32:    Section {
 ; OBJ32:      Name: .debug$S (2E 64 65 62 75 67 24 53)
 ; OBJ32:      Characteristics [ (0x42300040)
 ; OBJ32:      ]
 ; OBJ32:      Relocations [
-; OBJ32-NEXT:   0x59 IMAGE_REL_I386_SECREL _f
-; OBJ32-NEXT:   0x5D IMAGE_REL_I386_SECTION _f
-; OBJ32-NEXT:   0x70 IMAGE_REL_I386_SECREL _f
-; OBJ32-NEXT:   0x74 IMAGE_REL_I386_SECTION _f
+; OBJ32-NEXT:   0x64 IMAGE_REL_I386_SECREL _f
+; OBJ32-NEXT:   0x68 IMAGE_REL_I386_SECTION _f
+; OBJ32-NEXT:   0x7C IMAGE_REL_I386_SECREL _f
+; OBJ32-NEXT:   0x80 IMAGE_REL_I386_SECTION _f
 ; OBJ32-NEXT: ]
 ; OBJ32:      Subsection [
 ; OBJ32-NEXT:   SubSectionType: Symbols (0xF1)
 ; OBJ32:        ProcStart {
 ; OBJ32:          CodeSize: 0x10
 ; OBJ32:          DisplayName: f
 ; OBJ32:          LinkageName: _f
 ; OBJ32:        }

 ; X64-NEXT: .long   4
 ; Symbol subsection
 ; X64-NEXT: .long   241
 ; X64-NEXT: .long [[F1_END:.*]]-[[F1_START:.*]] #
 ; Compiler information record
 ; X64-NEXT: [[F1_START]]:
 ; X64-NEXT: .short [[C1_END:.*]]-[[C1_START:.*]] #
 ; X64:      [[C1_END]]:
+; X64-NEXT: [[F1_END]]:
+; X64-NEXT: .p2align  2
+; X64-NEXT: .long 241                     # Symbol subsection for f
+; X64-NEXT: .long [[SUBSEC_END:.*]]-[[SUBSEC_START:.*]] # Subsection size
+; X64-NEXT: [[SUBSEC_START]]:
 ; X64-NEXT: .short [[PROC_SEGMENT_END:.*]]-[[PROC_SEGMENT_START:.*]] #
 ; X64-NEXT: [[PROC_SEGMENT_START]]:
 ; X64-NEXT: .short  4423
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long [[END_OF_F]]-f
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   4098
 ; X64-NEXT: .secrel32 f
 ; X64-NEXT: .secidx f
 ; X64-NEXT: .byte   0
 ; X64-NEXT: .asciz "f"
 ; X64-NEXT: [[PROC_SEGMENT_END]]:
 ; X64-NEXT: .short  2
 ; X64-NEXT: .short  4431
-; X64-NEXT: [[F1_END]]:
+; X64-NEXT: [[SUBSEC_END]]:
 ; X64-NEXT: .p2align   2
 ; X64: .cv_linetable 0, f, [[END_OF_F]]
 ; X64: .cv_filechecksums
 ; X64: .cv_stringtable
 
 ; OBJ64:    Section {
 ; OBJ64:      Name: .debug$S (2E 64 65 62 75 67 24 53)
 ; OBJ64:      Characteristics [ (0x42300040)
 ; OBJ64:      ]
 ; OBJ64:      Relocations [
-; OBJ64-NEXT:   0x59 IMAGE_REL_AMD64_SECREL f
-; OBJ64-NEXT:   0x5D IMAGE_REL_AMD64_SECTION f
-; OBJ64-NEXT:   0x70 IMAGE_REL_AMD64_SECREL f
-; OBJ64-NEXT:   0x74 IMAGE_REL_AMD64_SECTION f
+; OBJ64-NEXT:   0x64 IMAGE_REL_AMD64_SECREL f
+; OBJ64-NEXT:   0x68 IMAGE_REL_AMD64_SECTION f
+; OBJ64-NEXT:   0x7C IMAGE_REL_AMD64_SECREL f
+; OBJ64-NEXT:   0x80 IMAGE_REL_AMD64_SECTION f
 ; OBJ64-NEXT: ]
 ; OBJ64:      Subsection [
 ; OBJ64-NEXT:   SubSectionType: Symbols (0xF1)
 ; OBJ64:        ProcStart {
 ; OBJ64:          CodeSize: 0x18
 ; OBJ64:          DisplayName: f
 ; OBJ64:          LinkageName: f
 ; OBJ64:        }

test/DebugInfo/COFF/multifunction.ll

 ; X86:      calll   _z
 ; X86:      .cv_loc 2 1 15 73 # source.c:15:73
 ; X86:      ret
 ; X86:      [[END_OF_F:.?Lfunc_end.*]]:
 ;
 ; X86-LABEL: .section        .debug$S,"dr"
 ; X86-NEXT: .p2align 2
 ; X86-NEXT: .long   4
-; Symbol subsection for x
 ; X86-NEXT: .long   241
 ; X86-NEXT: .long [[F1_END:.*]]-[[F1_START:.*]] #
 ; Compiler information record
 ; X86-NEXT: [[F1_START]]:
 ; X86-NEXT: .short [[C1_END:.*]]-[[C1_START:.*]] #
-; X86:      [[C1_END]]:
+; X86:      [[F1_END]]:
+; X86-NEXT: .p2align 2
+; Symbol subsection for x
+; X86-NEXT: .long   241
+; X86-NEXT: .long [[SUBSEC_END:.*]]-[[SUBSEC_START:.*]] #
+; X86-NEXT: [[SUBSEC_START]]:
 ; X86-NEXT: .short [[PROC_SEGMENT_END:.*]]-[[PROC_SEGMENT_START:.*]] #
 ; X86-NEXT: [[PROC_SEGMENT_START]]:
 ; X86-NEXT: .short  4422
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long [[END_OF_X]]-_x
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   4098
 ; X86-NEXT: .secrel32 _x
 ; X86-NEXT: .secidx _x
 ; X86-NEXT: .byte   0
 ; X86-NEXT: .asciz "x"
 ; X86-NEXT: [[PROC_SEGMENT_END]]:
 ; X86-NEXT: .short  2
 ; X86-NEXT: .short  4431
-; X86-NEXT: [[F1_END]]:
+; X86-NEXT: [[SUBSEC_END]]:
 ; X86-NEXT: .p2align 2
 ; Line table subsection for x
 ; X86: .cv_linetable 0, _x, [[END_OF_X]]
 ; Symbol subsection for y
 ; X86-NEXT: .long   241
 ; X86-NEXT: .long [[F1_END:.*]]-[[F1_START:.*]] #
-; Compiler information record
 ; X86-NEXT: [[F1_START]]:
-; X86-NEXT: .short [[C1_END:.*]]-[[C1_START:.*]] #
-; X86:      [[C1_END]]:
 ; X86-NEXT: .short [[PROC_SEGMENT_END:.*]]-[[PROC_SEGMENT_START:.*]] #
 ; X86-NEXT: [[PROC_SEGMENT_START]]:
 ; X86-NEXT: .short  4423
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long [[END_OF_Y]]-_y
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   4099
 ; X86-NEXT: .secrel32 _y
 ; X86-NEXT: .secidx _y
 ; X86-NEXT: .byte   0
 ; X86-NEXT: .asciz "y"
 ; X86-NEXT: [[PROC_SEGMENT_END]]:
 ; X86-NEXT: .short  2
 ; X86-NEXT: .short  4431
 ; X86-NEXT: [[F1_END]]:
 ; X86-NEXT: .p2align 2
 ; Line table subsection for y
 ; X86: .cv_linetable 1, _y, [[END_OF_Y]]
 ; Symbol subsection for f
 ; X86-NEXT: .long   241
 ; X86-NEXT: .long [[F1_END:.*]]-[[F1_START:.*]] #
-; Compiler information record
 ; X86-NEXT: [[F1_START]]:
-; X86-NEXT: .short [[C1_END:.*]]-[[C1_START:.*]] #
-; X86:      [[C1_END]]:
 ; X86-NEXT: .short [[PROC_SEGMENT_END:.*]]-[[PROC_SEGMENT_START:.*]] #
 ; X86-NEXT: [[PROC_SEGMENT_START]]:
 ; X86-NEXT: .short  4423
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long [[END_OF_F]]-_f
 ; X86-NEXT: .long   0

 ; X86: .cv_linetable 2, _f, [[END_OF_F]]
 ; X86: .cv_filechecksums
 ; X86: .cv_stringtable
 
 ; OBJ32:    Section {
 ; OBJ32:      Name: .debug$S (2E 64 65 62 75 67 24 53)
 ; OBJ32:      Characteristics [ (0x42300040)
 ; OBJ32:      ]
 ; OBJ32:      Relocations [
-; OBJ32-NEXT:   0x59 IMAGE_REL_I386_SECREL _x
-; OBJ32-NEXT:   0x5D IMAGE_REL_I386_SECTION _x
-; OBJ32-NEXT:   0x70 IMAGE_REL_I386_SECREL _x
-; OBJ32-NEXT:   0x74 IMAGE_REL_I386_SECTION _x
-; OBJ32-NEXT:   0xF5 IMAGE_REL_I386_SECREL _y
-; OBJ32-NEXT:   0xF9 IMAGE_REL_I386_SECTION _y
-; OBJ32-NEXT:   0x10C IMAGE_REL_I386_SECREL _y
-; OBJ32-NEXT:   0x110 IMAGE_REL_I386_SECTION _y
-; OBJ32-NEXT:   0x191 IMAGE_REL_I386_SECREL _f
-; OBJ32-NEXT:   0x195 IMAGE_REL_I386_SECTION _f
-; OBJ32-NEXT:   0x1A8 IMAGE_REL_I386_SECREL _f
-; OBJ32-NEXT:   0x1AC IMAGE_REL_I386_SECTION _f
+; OBJ32-NEXT:   0x64 IMAGE_REL_I386_SECREL _x
+; OBJ32-NEXT:   0x68 IMAGE_REL_I386_SECTION _x
+; OBJ32-NEXT:   0x7C IMAGE_REL_I386_SECREL _x
+; OBJ32-NEXT:   0x80 IMAGE_REL_I386_SECTION _x
+; OBJ32-NEXT:   0xD4 IMAGE_REL_I386_SECREL _y
+; OBJ32-NEXT:   0xD8 IMAGE_REL_I386_SECTION _y
+; OBJ32-NEXT:   0xEC IMAGE_REL_I386_SECREL _y
+; OBJ32-NEXT:   0xF0 IMAGE_REL_I386_SECTION _y
+; OBJ32-NEXT:   0x144 IMAGE_REL_I386_SECREL _f
+; OBJ32-NEXT:   0x148 IMAGE_REL_I386_SECTION _f
+; OBJ32-NEXT:   0x15C IMAGE_REL_I386_SECREL _f
+; OBJ32-NEXT:   0x160 IMAGE_REL_I386_SECTION _f
 ; OBJ32-NEXT: ]
 ; OBJ32:      Subsection [
 ; OBJ32-NEXT:   SubSectionType: Symbols (0xF1)
 ; OBJ32:        ProcStart {
 ; OBJ32:          Kind: S_LPROC32_ID (0x1146)
 ; OBJ32:          CodeSize: 0x6
 ; OBJ32:          DisplayName: x
 ; OBJ32:          LinkageName: _x

 ; X64:      callq   y
 ; X64:      .cv_loc 2 1 14 72 # source.c:14:72
 ; X64:      callq   z
 ; X64:      .cv_loc 2 1 15 73 # source.c:15:73
 ; X64:      addq    $40, %rsp
 ; X64-NEXT: ret
 ; X64:      [[END_OF_F:.?Lfunc_end.*]]:
 ;
+
 ; X64-LABEL: .section        .debug$S,"dr"
 ; X64-NEXT: .p2align 2
 ; X64-NEXT: .long   4
-; Symbol subsection for x
 ; X64-NEXT: .long   241
 ; X64-NEXT: .long [[F1_END:.*]]-[[F1_START:.*]] #
 ; Compiler information record
 ; X64-NEXT: [[F1_START]]:
 ; X64-NEXT: .short [[C1_END:.*]]-[[C1_START:.*]] #
-; X64:      [[C1_END]]:
+; X64:      [[F1_END]]:
+; X64-NEXT: .p2align 2
+; Symbol subsection for x
+; X64-NEXT: .long   241
+; X64-NEXT: .long  [[SUBSEC_END:.*]]-[[SUBSEC_START:.*]] #
+; X64-NEXT: [[SUBSEC_START]]:
 ; X64-NEXT: .short [[PROC_SEGMENT_END:.*]]-[[PROC_SEGMENT_START:.*]] #
 ; X64-NEXT: [[PROC_SEGMENT_START]]:
 ; X64-NEXT: .short  4422
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long [[END_OF_X]]-x
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   4098
 ; X64-NEXT: .secrel32 x
 ; X64-NEXT: .secidx x
 ; X64-NEXT: .byte   0
 ; X64-NEXT: .asciz "x"
 ; X64-NEXT: [[PROC_SEGMENT_END]]:
 ; X64-NEXT: .short  2
 ; X64-NEXT: .short  4431
-; X64-NEXT: [[F1_END]]:
+; X64-NEXT: [[SUBSEC_END]]:
 ; X64-NEXT: .p2align 2
 ; Line table subsection for x
 ; X64: .cv_linetable 0, x, [[END_OF_X]]
 ; Symbol subsection for y
 ; X64-NEXT: .long   241
 ; X64-NEXT: .long [[F1_END:.*]]-[[F1_START:.*]] #
-; Compiler information record
 ; X64-NEXT: [[F1_START]]:
-; X64-NEXT: .short [[C1_END:.*]]-[[C1_START:.*]] #
-; X64:      [[C1_END]]:
 ; X64-NEXT: .short [[PROC_SEGMENT_END:.*]]-[[PROC_SEGMENT_START:.*]] #
 ; X64-NEXT: [[PROC_SEGMENT_START]]:
 ; X64-NEXT: .short  4423
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long [[END_OF_Y]]-y
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   4099
 ; X64-NEXT: .secrel32 y
 ; X64-NEXT: .secidx y
 ; X64-NEXT: .byte   0
 ; X64-NEXT: .asciz "y"
 ; X64-NEXT: [[PROC_SEGMENT_END]]:
 ; X64-NEXT: .short  2
 ; X64-NEXT: .short  4431
 ; X64-NEXT: [[F1_END]]:
 ; X64-NEXT: .p2align 2
 ; Line table subsection for y
 ; X64: .cv_linetable 1, y, [[END_OF_Y]]
 ; Symbol subsection for f
 ; X64-NEXT: .long   241
 ; X64-NEXT: .long [[F1_END:.*]]-[[F1_START:.*]] #
-; Compiler information record
-; X64-NEXT: [[F1_START]]:
-; X64-NEXT: .short [[C1_END:.*]]-[[C1_START:.*]] #
-; X64:      [[C1_END]]:
+; X64:      [[F1_START]]:
 ; X64-NEXT: .short [[PROC_SEGMENT_END:.*]]-[[PROC_SEGMENT_START:.*]] #
 ; X64-NEXT: [[PROC_SEGMENT_START]]:
 ; X64-NEXT: .short  4423
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long [[END_OF_F]]-f
 ; X64-NEXT: .long   0

 ; String table
 ; X64: .cv_stringtable
 
 ; OBJ64:    Section {
 ; OBJ64:      Name: .debug$S (2E 64 65 62 75 67 24 53)
 ; OBJ64:      Characteristics [ (0x42300040)
 ; OBJ64:      ]
 ; OBJ64:      Relocations [
-; OBJ64-NEXT:   0x59 IMAGE_REL_AMD64_SECREL x
-; OBJ64-NEXT:   0x5D IMAGE_REL_AMD64_SECTION x
-; OBJ64-NEXT:   0x70 IMAGE_REL_AMD64_SECREL x
-; OBJ64-NEXT:   0x74 IMAGE_REL_AMD64_SECTION x
-; OBJ64-NEXT:   0x101 IMAGE_REL_AMD64_SECREL y
-; OBJ64-NEXT:   0x105 IMAGE_REL_AMD64_SECTION y
-; OBJ64-NEXT:   0x118 IMAGE_REL_AMD64_SECREL y
-; OBJ64-NEXT:   0x11C IMAGE_REL_AMD64_SECTION y
-; OBJ64-NEXT:   0x1A9 IMAGE_REL_AMD64_SECREL f
-; OBJ64-NEXT:   0x1AD IMAGE_REL_AMD64_SECTION f
-; OBJ64-NEXT:   0x1C0 IMAGE_REL_AMD64_SECREL f
-; OBJ64-NEXT:   0x1C4 IMAGE_REL_AMD64_SECTION f
+; OBJ64-NEXT:   0x64 IMAGE_REL_AMD64_SECREL x
+; OBJ64-NEXT:   0x68 IMAGE_REL_AMD64_SECTION x
+; OBJ64-NEXT:   0x7C IMAGE_REL_AMD64_SECREL x
+; OBJ64-NEXT:   0x80 IMAGE_REL_AMD64_SECTION x
+; OBJ64-NEXT:   0xE0 IMAGE_REL_AMD64_SECREL y
+; OBJ64-NEXT:   0xE4 IMAGE_REL_AMD64_SECTION y
+; OBJ64-NEXT:   0xF8 IMAGE_REL_AMD64_SECREL y
+; OBJ64-NEXT:   0xFC IMAGE_REL_AMD64_SECTION y
+; OBJ64-NEXT:   0x15C IMAGE_REL_AMD64_SECREL f
+; OBJ64-NEXT:   0x160 IMAGE_REL_AMD64_SECTION f
+; OBJ64-NEXT:   0x174 IMAGE_REL_AMD64_SECREL f
+; OBJ64-NEXT:   0x178 IMAGE_REL_AMD64_SECTION f
 ; OBJ64-NEXT: ]
 ; OBJ64:      Subsection [
 ; OBJ64-NEXT:   SubSectionType: Symbols (0xF1)
 ; OBJ64:        ProcStart {
 ; OBJ64:          Kind: S_LPROC32_ID (0x1146)
 ; OBJ64:          CodeSize: 0xE
 ; OBJ64:          DisplayName: x
 ; OBJ64:          LinkageName: x

test/DebugInfo/COFF/pr28747.ll

 ; RUN: llc < %s | FileCheck %s
-
 ; CHECK:             .section .debug$S,"dr"{{$}}
 ; CHECK-NEXT:        .p2align 2
 ; CHECK-NEXT:        .long 4
+; CHECK-NEXT:        .long  241
+; CHECK-NEXT:        .long  [[SUBSEC_END:.*]]-[[SUBSEC_START:.*]] # Subsection size
+; CHECK-NEXT:        [[SUBSEC_START]]:
+; CHECK-NEXT:        .short [[C1_END:.*]]-[[C1_START:.*]] # Record length
+; CHECK:             [[C1_END]]:
+; CHECK-NEXT:        [[SUBSEC_END]]:
+; CHECK-NEXT:        .p2align 2
 ; CHECK-NEXT:        .cv_filechecksums
 ; CHECK-NEXT:        .cv_stringtable
 
 target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
 target triple = "i686-pc-windows-msvc18.0.0"
 
 define void @baz() {
 entry:

test/DebugInfo/COFF/simple.ll

 ; X86:      ret
 ; X86:      [[END_OF_F:Lfunc_end.*]]:
 ;
 ; X86-LABEL: .section        .debug$S,"dr"
 ; X86-NEXT: .p2align 2
 ; X86-NEXT: .long   4
 ; Symbol subsection
 ; X86-NEXT: .long   241
 ; X86-NEXT: .long [[F1_END:.*]]-[[F1_START:.*]] #
 ; Compiler information record
 ; X86-NEXT: [[F1_START]]:
 ; X86-NEXT: .short [[C1_END:.*]]-[[C1_START:.*]] #
 ; X86:      [[C1_END]]:
+; X86-NEXT: [[F1_END]]:
+; X86-NEXT: .p2align  2
+; X86-NEXT: .long 241  # Symbol subsection for f
+; X86-NEXT: .long [[SUBSEC_END:.*]]-[[SUBSEC_START:.*]] # Subsection size
+; X86-NEXT: [[SUBSEC_START]]:
 ; X86-NEXT: .short [[PROC_SEGMENT_END:.*]]-[[PROC_SEGMENT_START:.*]] #
 ; X86-NEXT: [[PROC_SEGMENT_START]]:
 ; X86-NEXT: .short  4423
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long [[END_OF_F]]-_f
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   0
 ; X86-NEXT: .long   4098
 ; X86-NEXT: .secrel32 _f
 ; X86-NEXT: .secidx _f
 ; X86-NEXT: .byte   0
 ; X86-NEXT: .asciz "f"
 ; X86-NEXT: [[PROC_SEGMENT_END]]:
 ; X86-NEXT: .short  2
 ; X86-NEXT: .short  4431
-; X86-NEXT: [[F1_END]]:
+; X86-NEXT: [[SUBSEC_END]]:
 ; X86-NEXT: .p2align 2
 ; Line table
 ; X86-NEXT: .cv_linetable 0, _f, [[END_OF_F]]
 ; File index to string table offset subsection
 ; X86-NEXT: .cv_filechecksums
 ; String table
 ; X86-NEXT: .cv_stringtable
 
 ; OBJ32:    Section {
 ; OBJ32:      Name: .debug$S (2E 64 65 62 75 67 24 53)
 ; OBJ32:      Characteristics [ (0x42300040)
 ; OBJ32:      ]
 ; OBJ32:      Relocations [
-; OBJ32-NEXT:   0x59 IMAGE_REL_I386_SECREL _f
-; OBJ32-NEXT:   0x5D IMAGE_REL_I386_SECTION _f
-; OBJ32-NEXT:   0x70 IMAGE_REL_I386_SECREL _f
-; OBJ32-NEXT:   0x74 IMAGE_REL_I386_SECTION _f
+; OBJ32-NEXT:   0x64 IMAGE_REL_I386_SECREL _f
+; OBJ32-NEXT:   0x68 IMAGE_REL_I386_SECTION _f
+; OBJ32-NEXT:   0x7C IMAGE_REL_I386_SECREL _f
+; OBJ32-NEXT:   0x80 IMAGE_REL_I386_SECTION _f
 ; OBJ32-NEXT: ]
 ; OBJ32:      Subsection [
 ; OBJ32-NEXT:   SubSectionType: Symbols (0xF1)
 ; OBJ32:        ProcStart {
 ; OBJ32:          CodeSize: 0x6
 ; OBJ32:          DisplayName: f
 ; OBJ32:          LinkageName: _f
 ; OBJ32:        }

 ; X64-NEXT: .long   4
 ; Symbol subsection
 ; X64-NEXT: .long   241
 ; X64-NEXT: .long [[F1_END:.*]]-[[F1_START:.*]] #
 ; Compiler information record
 ; X64-NEXT: [[F1_START]]:
 ; X64-NEXT: .short [[C1_END:.*]]-[[C1_START:.*]] #
 ; X64:      [[C1_END]]:
+; X64-NEXT: [[F1_END]]:
+; X64-NEXT: .p2align  2
+; X64-NEXT: .long 241  # Symbol subsection for f
+; X64-NEXT: .long [[SUBSEC_END:.*]]-[[SUBSEC_START:.*]] # Subsection size
+; X64-NEXT: [[SUBSEC_START]]:
 ; X64-NEXT: .short [[PROC_SEGMENT_END:.*]]-[[PROC_SEGMENT_START:.*]] #
 ; X64-NEXT: [[PROC_SEGMENT_START]]:
 ; X64-NEXT: .short  4423
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long [[END_OF_F]]-f
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   0
 ; X64-NEXT: .long   4098
 ; X64-NEXT: .secrel32 f
 ; X64-NEXT: .secidx f
 ; X64-NEXT: .byte   0
 ; X64-NEXT: .asciz "f"
 ; X64-NEXT: [[PROC_SEGMENT_END]]:
 ; X64-NEXT: .short  2
 ; X64-NEXT: .short  4431
-; X64-NEXT: [[F1_END]]:
+; X64-NEXT: [[SUBSEC_END]]:
 ; X64-NEXT: .p2align   2
 ; Line table
 ; X64-NEXT: .cv_linetable 0, f, [[END_OF_F]]
 ; File index to string table offset subsection
 ; X64-NEXT: .cv_filechecksums
 ; String table
 ; X64-NEXT: .cv_stringtable
 
 ; OBJ64:    Section {
 ; OBJ64:      Name: .debug$S (2E 64 65 62 75 67 24 53)
 ; OBJ64:      Characteristics [ (0x42300040)
 ; OBJ64:      ]
 ; OBJ64:      Relocations [
-; OBJ64-NEXT:   0x59 IMAGE_REL_AMD64_SECREL f
-; OBJ64-NEXT:   0x5D IMAGE_REL_AMD64_SECTION f
-; OBJ64-NEXT:   0x70 IMAGE_REL_AMD64_SECREL f
-; OBJ64-NEXT:   0x74 IMAGE_REL_AMD64_SECTION f
+; OBJ64-NEXT:   0x64 IMAGE_REL_AMD64_SECREL f
+; OBJ64-NEXT:   0x68 IMAGE_REL_AMD64_SECTION f
+; OBJ64-NEXT:   0x7C IMAGE_REL_AMD64_SECREL f
+; OBJ64-NEXT:   0x80 IMAGE_REL_AMD64_SECTION f
 ; OBJ64-NEXT: ]
 ; OBJ64:      Subsection [
 ; OBJ64-NEXT:   SubSectionType: Symbols (0xF1)
 ; OBJ64:        ProcStart {
 ; OBJ64:          CodeSize: 0xE
 ; OBJ64:          DisplayName: f
 ; OBJ64:          LinkageName: f
 ; OBJ64:        }

test/MC/ARM/coff-debugging-secrel.ll

 ; CHECK-ITANIUM:   }
 ; CHECK-ITANIUM:   Section {{.*}}.debug_pubnames {
 ; CHECK-ITANIUM:     0x6 IMAGE_REL_ARM_SECREL .debug_info
 ; CHECK-ITANIUM:   }
 ; CHECK-ITANIUM: ]
 
 ; CHECK-MSVC: Relocations [
 ; CHECK-MSVC:   Section {{.*}} .debug$S {
-; CHECK-MSVC:     0x5A IMAGE_REL_ARM_SECREL function
-; CHECK-MSVC:     0x5E IMAGE_REL_ARM_SECTION function
-; CHECK-MSVC:     0x78 IMAGE_REL_ARM_SECREL function
-; CHECK-MSVC:     0x7C IMAGE_REL_ARM_SECTION function
+; CHECK-MSVC:     0x64 IMAGE_REL_ARM_SECREL function
+; CHECK-MSVC:     0x68 IMAGE_REL_ARM_SECTION function
+; CHECK-MSVC:     0x80 IMAGE_REL_ARM_SECREL function
+; CHECK-MSVC:     0x84 IMAGE_REL_ARM_SECTION function
 ; CHECK-MSVC:   }
 ; CHECK-MSVC: ]
 

test/MC/COFF/cv-compiler-info.ll

 
 attributes #0 = { nounwind sspstrong "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="pentium4" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!3, !7, !8}
 !llvm.ident = !{!9}
 
 !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 4.0.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
-; The debug$S section should begin with an S_COMPILE3 record that identifies the
+; One .debug$S section should contain an S_COMPILE3 record that identifies the
 ; source language and the version of the compiler based on the DICompileUnit.
 ; CHECK:  .section  .debug$S,"dr"
-; CHECK:    .p2align  2
-; CHECK:    .long 4                       # Debug section magic
-; CHECK:    .long 241                     # Symbol subsection for foo
-; CHECK:    .long Ltmp3-Ltmp2             # Subsection size
-; CHECK:  Ltmp2:
-; CHECK:    .short  Ltmp5-Ltmp4           # Record length
-; CHECK:  Ltmp4:
 ; CHECK:    .short  4412                  # Record kind: S_COMPILE3
 ; CHECK:    .long 1                       # Flags and language
 ; CHECK:    .short  7                     # CPUType
 ; CHECK:    .short  4                     # Frontend version
 ; CHECK:    .short  0
 ; CHECK:    .short  0
 ; CHECK:    .short  0
 ; CHECK:    .short  [[BACKEND_VERSION:[0-9]+]]  # Backend version
 ; CHECK:    .short  0
 ; CHECK:    .short  0
 ; CHECK:    .short  0
 ; CHECK:    .asciz  "clang version 4.0.0 "  # Null-terminated compiler version string
-; CHECK:  Ltmp5:
+; CHECK-NOT: .short 4412                  # Record kind: S_COMPILE3
 !1 = !DIFile(filename: "D:\5Csrc\5Cscopes\5Cfoo.cpp", directory: "D:\5Csrc\5Cscopes\5Cclang")
 !2 = !{}
 !3 = !{i32 6, !"Linker Options", !4}
 !4 = !{!5, !6}
 !5 = !{!"/DEFAULTLIB:libcmtd.lib"}
 !6 = !{!"/DEFAULTLIB:oldnames.lib"}
 !7 = !{i32 2, !"CodeView", i32 1}
 !8 = !{i32 2, !"Debug Info Version", i32 3}
 !9 = !{!"clang version 4.0.0 "}
 !10 = distinct !DISubprogram(name: "foo", linkageName: "\01?foo@@YAHXZ", scope: !1, file: !1, line: 1, type: !11, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
 !11 = !DISubroutineType(types: !12)
 !12 = !{!13}
 !13 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !14 = !DILocation(line: 2, scope: !10)