[codeview] Shrink inlined call site line info tables

For a fully inlined call chain like a -> b -> c -> d, we were emitting
line info for 'd' 3 separate times: once for d's actual InlineSite line
table, and twice for 'b' and 'c'. This is particularly inefficient when
all these functions are in different headers, because now we need to
encode the file change. Windbg was coping with our suboptimal output, so
this should not be noticeable from the debugger.

llvm-svn: 275502

5 files changed, 189 insertions, 23 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h
index 31da1b11fa4..e4bbd61d4ce 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h
@@ -78,6 +78,9 @@ class LLVM_LIBRARY_VISIBILITY CodeViewDebug : public DebugHandlerBase {
     SmallVector<LocalVariable, 1> InlinedLocals;
     SmallVector<const DILocation *, 1> ChildSites;
     const DISubprogram *Inlinee = nullptr;
+
+    /// The ID of the inline site or function used with .cv_loc. Not a type
+    /// index.
     unsigned SiteFuncId = 0;
   };
 
diff --git a/llvm/lib/MC/MCCodeView.cpp b/llvm/lib/MC/MCCodeView.cpp
index d3f2aa2a80c..65cff41abeb 100644
--- a/llvm/lib/MC/MCCodeView.cpp
+++ b/llvm/lib/MC/MCCodeView.cpp
@@ -302,7 +302,7 @@ void CodeViewContext::encodeInlineLineTable(MCAsmLayout &Layout,
   StartLoc.setFileNum(Frag.StartFileId);
   StartLoc.setLine(Frag.StartLineNum);
   const MCCVLineEntry *LastLoc = &StartLoc;
-  bool WithinFunction = true;
+  bool HaveOpenRange = false;
 
   SmallVectorImpl<char> &Buffer = Frag.getContents();
   Buffer.clear(); // Clear old contents if we went through relaxation.
@@ -310,16 +310,22 @@ void CodeViewContext::encodeInlineLineTable(MCAsmLayout &Layout,
     if (!InlinedFuncIds.count(Loc.getFunctionId())) {
       // We've hit a cv_loc not attributed to this inline call site. Use this
       // label to end the PC range.
-      if (WithinFunction) {
+      if (HaveOpenRange) {
         unsigned Length =
             computeLabelDiff(Layout, LastLoc->getLabel(), Loc.getLabel());
         compressAnnotation(BinaryAnnotationsOpCode::ChangeCodeLength, Buffer);
         compressAnnotation(Length, Buffer);
       }
-      WithinFunction = false;
+      HaveOpenRange = false;
       continue;
     }
-    WithinFunction = true;
+
+    // If we've already opened the function and we're at an indirectly inlined
+    // location, continue until the next directly inlined location.
+    bool DirectlyInlined = Loc.getFunctionId() == Frag.SiteFuncId;
+    if (!DirectlyInlined && HaveOpenRange)
+      continue;
+    HaveOpenRange = true;
 
     if (Loc.getFileNum() != LastLoc->getFileNum()) {
       // File ids are 1 based, and each file checksum table entry is 8 bytes
@@ -358,7 +364,7 @@ void CodeViewContext::encodeInlineLineTable(MCAsmLayout &Layout,
     LastLoc = &Loc;
   }
 
-  assert(WithinFunction);
+  assert(HaveOpenRange);
 
   unsigned EndSymLength =
       computeLabelDiff(Layout, LastLoc->getLabel(), Frag.getFnEndSym());
diff --git a/llvm/test/DebugInfo/COFF/inlining-header.ll b/llvm/test/DebugInfo/COFF/inlining-header.ll
new file mode 100644
index 00000000000..6a57e182a32
--- /dev/null
+++ b/llvm/test/DebugInfo/COFF/inlining-header.ll
@@ -0,0 +1,167 @@
+; RUN: llc -mcpu=core2 -mtriple=i686-pc-win32 < %s | FileCheck %s --check-prefix=ASM
+; RUN: llc -mcpu=core2 -mtriple=i686-pc-win32 < %s -filetype=obj | llvm-readobj -codeview | FileCheck %s --check-prefix=OBJ
+
+; This C++ source should run and you should be able to step through the volatile
+; modifications to x in windbg.
+; # 1 "t.cpp" 2
+; volatile int x;
+;
+; # 1 "./t.h" 1
+; inline void f() {
+;   x += 3;
+; }
+; # 3 "t.cpp" 2
+; inline __forceinline void g() {
+;   x += 2;
+;   f();
+;   x += 2;
+; }
+; int main() {
+;   x += 1;
+;   g();
+;   x += 1;
+;   return x;
+; }
+
+; ASM: _main:                                  # @main
+; ASM: Lfunc_begin0:
+; ASM: # BB#0:                                 # %entry
+; ASM:         .cv_file        1 "D:\\src\\llvm\\build\\t.cpp"
+; ASM:         .cv_loc 0 1 9 5 is_stmt 0       # t.cpp:9:5
+; ASM:         incl    "?x@@3HC"
+; ASM:         .cv_loc 1 1 4 5                 # t.cpp:4:5
+; ASM:         addl    $2, "?x@@3HC"
+; ASM:         .cv_file        2 "D:\\src\\llvm\\build\\t.h"
+; ASM:         .cv_loc 2 2 2 5                 # ./t.h:2:5
+; ASM:         addl    $3, "?x@@3HC"
+; ASM:         .cv_loc 1 1 6 5                 # t.cpp:6:5
+; ASM:         addl    $2, "?x@@3HC"
+; ASM:         .cv_loc 0 1 11 5                # t.cpp:11:5
+; ASM:         incl    "?x@@3HC"
+; ASM:         .cv_loc 0 1 12 10               # t.cpp:12:10
+; ASM:         movl    "?x@@3HC", %eax
+; ASM:         .cv_loc 0 1 12 3                # t.cpp:12:3
+; ASM:         retl
+
+; OBJ: Subsection [
+; OBJ:   SubSectionType: InlineeLines (0xF6)
+; OBJ:   SubSectionSize: 0x1C
+; OBJ:   InlineeSourceLine {
+; OBJ:     Inlinee: g (0x1002)
+; OBJ:     FileID: D:\src\llvm\build\t.cpp (0x0)
+; OBJ:     SourceLineNum: 3
+; OBJ:   }
+; OBJ:   InlineeSourceLine {
+; OBJ:     Inlinee: f (0x1003)
+; OBJ:     FileID: D:\src\llvm\build\t.h (0x8)
+; OBJ:     SourceLineNum: 1
+; OBJ:   }
+; OBJ: ]
+
+
+; OBJ: Subsection [
+; OBJ:   SubSectionType: Symbols (0xF1)
+; OBJ:   SubSectionSize: 0x62
+; OBJ:   ProcStart {
+; OBJ:     Kind: S_GPROC32_ID (0x1147)
+; OBJ:     FunctionType: main (0x1005)
+; OBJ:     CodeOffset: _main+0x0
+; OBJ:     Segment: 0x0
+; OBJ:     Flags [ (0x0)
+; OBJ:     ]
+; OBJ:     DisplayName: main
+; OBJ:     LinkageName: _main
+; OBJ:   }
+
+; Previously, g's InlineSite referenced t.h, which was wasteful.
+; OBJ:        InlineSite {
+; OBJ:          Inlinee: g (0x1002)
+; OBJ:          BinaryAnnotations [
+; OBJ-NEXT:       ChangeCodeOffsetAndLineOffset: {CodeOffset: 0x6, LineOffset: 1}
+; OBJ-NEXT:       ChangeCodeOffsetAndLineOffset: {CodeOffset: 0xE, LineOffset: 2}
+; OBJ-NEXT:       ChangeCodeLength: 0x7
+; OBJ-NEXT:     ]
+; OBJ:        }
+
+; OBJ:   InlineSite {
+; OBJ:     Inlinee: f (0x1003)
+; OBJ:     BinaryAnnotations [
+; OBJ-NEXT:  ChangeCodeOffsetAndLineOffset: {CodeOffset: 0xD, LineOffset: 1}
+; OBJ-NEXT:  ChangeCodeLength: 0x7
+; OBJ-NEXT:]
+; OBJ:   }
+; OBJ:   InlineSiteEnd {
+; OBJ:   }
+; OBJ:   InlineSiteEnd {
+; OBJ:   }
+; OBJ:   ProcEnd {
+; OBJ:   }
+; OBJ: ]
+
+; ModuleID = 't.cpp'
+source_filename = "t.cpp"
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc19.0.24210"
+
+@"\01?x@@3HC" = global i32 0, align 4
+
+; Function Attrs: norecurse nounwind uwtable
+define i32 @main() local_unnamed_addr #0 !dbg !11 {
+entry:
+  %0 = load volatile i32, i32* @"\01?x@@3HC", align 4, !dbg !14, !tbaa !15
+  %add = add nsw i32 %0, 1, !dbg !14
+  store volatile i32 %add, i32* @"\01?x@@3HC", align 4, !dbg !14, !tbaa !15
+  %1 = load volatile i32, i32* @"\01?x@@3HC", align 4, !dbg !19, !tbaa !15
+  %add.i = add nsw i32 %1, 2, !dbg !19
+  store volatile i32 %add.i, i32* @"\01?x@@3HC", align 4, !dbg !19, !tbaa !15
+  %2 = load volatile i32, i32* @"\01?x@@3HC", align 4, !dbg !24, !tbaa !15
+  %add.i.i = add nsw i32 %2, 3, !dbg !24
+  store volatile i32 %add.i.i, i32* @"\01?x@@3HC", align 4, !dbg !24, !tbaa !15
+  %3 = load volatile i32, i32* @"\01?x@@3HC", align 4, !dbg !28, !tbaa !15
+  %add1.i = add nsw i32 %3, 2, !dbg !28
+  store volatile i32 %add1.i, i32* @"\01?x@@3HC", align 4, !dbg !28, !tbaa !15
+  %4 = load volatile i32, i32* @"\01?x@@3HC", align 4, !dbg !29, !tbaa !15
+  %add1 = add nsw i32 %4, 1, !dbg !29
+  store volatile i32 %add1, i32* @"\01?x@@3HC", align 4, !dbg !29, !tbaa !15
+  %5 = load volatile i32, i32* @"\01?x@@3HC", align 4, !dbg !30, !tbaa !15
+  ret i32 %5, !dbg !31
+}
+
+attributes #0 = { norecurse nounwind uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!7, !8, !9}
+!llvm.ident = !{!10}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.9.0 (trunk 275430) (llvm/trunk 275433)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !3)
+!1 = !DIFile(filename: "t.cpp", directory: "D:\5Csrc\5Cllvm\5Cbuild")
+!2 = !{}
+!3 = !{!4}
+!4 = distinct !DIGlobalVariable(name: "x", linkageName: "\01?x@@3HC", scope: !0, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true, variable: i32* @"\01?x@@3HC")
+!5 = !DIDerivedType(tag: DW_TAG_volatile_type, baseType: !6)
+!6 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!7 = !{i32 2, !"CodeView", i32 1}
+!8 = !{i32 2, !"Debug Info Version", i32 3}
+!9 = !{i32 1, !"PIC Level", i32 2}
+!10 = !{!"clang version 3.9.0 (trunk 275430) (llvm/trunk 275433)"}
+!11 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 8, type: !12, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !2)
+!12 = !DISubroutineType(types: !13)
+!13 = !{!6}
+!14 = !DILocation(line: 9, column: 5, scope: !11)
+!15 = !{!16, !16, i64 0}
+!16 = !{!"int", !17, i64 0}
+!17 = !{!"omnipotent char", !18, i64 0}
+!18 = !{!"Simple C++ TBAA"}
+!19 = !DILocation(line: 4, column: 5, scope: !20, inlinedAt: !23)
+!20 = distinct !DISubprogram(name: "g", linkageName: "\01?g@@YAXXZ", scope: !1, file: !1, line: 3, type: !21, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !2)
+!21 = !DISubroutineType(types: !22)
+!22 = !{null}
+!23 = distinct !DILocation(line: 10, column: 3, scope: !11)
+!24 = !DILocation(line: 2, column: 5, scope: !25, inlinedAt: !27)
+!25 = distinct !DISubprogram(name: "f", linkageName: "\01?f@@YAXXZ", scope: !26, file: !26, line: 1, type: !21, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !2)
+!26 = !DIFile(filename: "./t.h", directory: "D:\5Csrc\5Cllvm\5Cbuild")
+!27 = distinct !DILocation(line: 5, column: 3, scope: !20, inlinedAt: !23)
+!28 = !DILocation(line: 6, column: 5, scope: !20, inlinedAt: !23)
+!29 = !DILocation(line: 11, column: 5, scope: !11)
+!30 = !DILocation(line: 12, column: 10, scope: !11)
+!31 = !DILocation(line: 12, column: 3, scope: !11)
diff --git a/llvm/test/DebugInfo/COFF/inlining.ll b/llvm/test/DebugInfo/COFF/inlining.ll
index 4e678cd23a3..815111f9cbf 100644
--- a/llvm/test/DebugInfo/COFF/inlining.ll
+++ b/llvm/test/DebugInfo/COFF/inlining.ll
@@ -182,17 +182,12 @@
 ; OBJ:     PtrParent: 0x0
 ; OBJ:     PtrEnd: 0x0
 ; OBJ:     Inlinee: bar (0x1002)
-; OBJ:     BinaryAnnotations [
-; OBJ-NEXT:  ChangeCodeOffsetAndLineOffset: {CodeOffset: 0x8, LineOffset: 1}
-; OBJ-NEXT:  ChangeLineOffset: -6
-; OBJ-NEXT:  ChangeCodeOffset: 0x7
-; OBJ-NEXT:  ChangeCodeOffsetAndLineOffset: {CodeOffset: 0xA, LineOffset: 1}
-; OBJ-NEXT:  ChangeCodeOffsetAndLineOffset: {CodeOffset: 0x6, LineOffset: 1}
-; OBJ-NEXT:  ChangeCodeOffsetAndLineOffset: {CodeOffset: 0x7, LineOffset: 1}
-; OBJ-NEXT:  ChangeLineOffset: 5
-; OBJ-NEXT:  ChangeCodeOffset: 0x7
-; OBJ-NEXT:  ChangeCodeLength: 0x7
-; OBJ:     ]
+; OBJ:      BinaryAnnotations [
+; OBJ-NEXT:   ChangeCodeOffsetAndLineOffset: {CodeOffset: 0x8, LineOffset: 1}
+; OBJ-NEXT:   ChangeLineOffset: 2
+; OBJ-NEXT:   ChangeCodeOffset: 0x25
+; OBJ-NEXT:   ChangeCodeLength: 0x7
+; OBJ:      ]
 ; OBJ:   }
 ; OBJ:   InlineSite {
 ; OBJ:     PtrParent: 0x0
diff --git a/llvm/test/MC/COFF/cv-inline-linetable.s b/llvm/test/MC/COFF/cv-inline-linetable.s
index 22aa48f8bc8..67c6da2ab09 100644
--- a/llvm/test/MC/COFF/cv-inline-linetable.s
+++ b/llvm/test/MC/COFF/cv-inline-linetable.s
@@ -90,13 +90,8 @@ Ltmp4:
 # CHECK:      PtrEnd: 0x0
 # CHECK:      Inlinee: bar (0x1003)
 # CHECK:      BinaryAnnotations [
-# CHECK:        ChangeLineOffset: -6
-# CHECK:        ChangeCodeOffset: 0xF
-# CHECK:        ChangeCodeOffsetAndLineOffset: {CodeOffset: 0xA, LineOffset: 1}
-# CHECK:        ChangeCodeOffsetAndLineOffset: {CodeOffset: 0x6, LineOffset: 1}
-# CHECK:        ChangeCodeOffsetAndLineOffset: {CodeOffset: 0x7, LineOffset: 1}
-# CHECK:        ChangeLineOffset: 5
-# CHECK:        ChangeCodeOffset: 0x7
+# CHECK:        ChangeLineOffset: 2
+# CHECK:        ChangeCodeOffset: 0x2D
 # CHECK:        ChangeCodeLength: 0x7
 # CHECK:      ]
 # CHECK:    }