[CodeView] Add CodeView support for PGO debug information

This change adds debug information about whether PGO is being used or
not.

Microsoft performance tooling (e.g. xperf, WPA) uses this information to
show whether functions are optimized with PGO or not, as well as whether
PGO information is invalid.

This information is useful for validating whether training scenarios are
providing good coverage of real world scenarios, showing if profile data
is out of date, etc.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D99994

2 files changed, 172 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 936ac5aa6399..b3f1b95b16aa 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -804,6 +804,9 @@ void CodeViewDebug::emitCompilerInformation() {
   // The low byte of the flags indicates the source language.
   Flags = MapDWLangToCVLang(CU->getSourceLanguage());
   // TODO:  Figure out which other flags need to be set.
+  if (MMI->getModule()->getProfileSummary(/*IsCS*/ false) != nullptr) {
+    Flags |= static_cast<uint32_t>(CompileSym3Flags::PGO);
+  }
 
   OS.AddComment("Flags and language");
   OS.emitInt32(Flags);
@@ -1428,6 +1431,10 @@ void CodeViewDebug::beginFunctionImpl(const MachineFunction *MF) {
   if (Asm->TM.getOptLevel() != CodeGenOpt::None &&
       !GV.hasOptSize() && !GV.hasOptNone())
     FPO |= FrameProcedureOptions::OptimizedForSpeed;
+  if (GV.hasProfileData()) {
+    FPO |= FrameProcedureOptions::ValidProfileCounts;
+    FPO |= FrameProcedureOptions::ProfileGuidedOptimization;
+  }
   // FIXME: Set GuardCfg when it is implemented.
   CurFn->FrameProcOpts = FPO;
 
diff --git a/llvm/test/DebugInfo/COFF/pgo.ll b/llvm/test/DebugInfo/COFF/pgo.ll
new file mode 100644
index 000000000000..2aa880ddfd0f
--- /dev/null
+++ b/llvm/test/DebugInfo/COFF/pgo.ll
@@ -0,0 +1,165 @@
+; RUN: llc < %s -filetype=obj | llvm-readobj --codeview - | FileCheck %s
+
+; CHECK: Compile3Sym {
+; CHECK:   Flags [ (0x40000)
+; CHECK:     PGO (0x40000)
+
+; CHECK: DisplayName: foo
+; CHECK: Kind: S_FRAMEPROC (0x1012)
+; CHECK:   ProfileGuidedOptimization (0x40000)
+; CHECK:   ValidProfileCounts (0x80000)
+
+; CHECK: DisplayName: foo2
+; CHECK: Kind: S_FRAMEPROC (0x1012)
+; CHECK:   ProfileGuidedOptimization (0x40000)
+; CHECK:   ValidProfileCounts (0x80000)
+
+; CHECK: DisplayName: bar
+; CHECK: Kind: S_FRAMEPROC (0x1012)
+; CHECK:   ProfileGuidedOptimization (0x40000)
+; CHECK:   ValidProfileCounts (0x80000)
+
+; CHECK: DisplayName: main
+; CHECK: Kind: S_FRAMEPROC (0x1012)
+; CHECK-NOT:   ProfileGuidedOptimization (0x40000)
+; CHECK-NOT:   ValidProfileCounts (0x80000)
+
+source_filename = "pgo.cpp"
+target datalayout = "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc19.28.29912"
+
+define dso_local i32 @"?foo@@YAHH@Z"(i32 %b) local_unnamed_addr #1 !dbg !43 !prof !49 {
+entry:
+  call void @llvm.dbg.value(metadata i32 %b, metadata !48, metadata !DIExpression()), !dbg !50
+  %mul = mul nsw i32 %b, 10, !dbg !51
+  ret i32 %mul, !dbg !51
+}
+
+define dso_local i32 @"?foo2@@YAHH@Z"(i32 %a) local_unnamed_addr #1 !dbg !52 !prof !55 {
+entry:
+  call void @llvm.dbg.value(metadata i32 %a, metadata !54, metadata !DIExpression()), !dbg !56
+  %mul = mul nsw i32 %a, 5, !dbg !57
+  ret i32 %mul, !dbg !57
+}
+
+define dso_local i32 @"?bar@@YAHH@Z"(i32 %num) local_unnamed_addr #1 !dbg !58 !prof !55 {
+entry:
+  call void @llvm.dbg.value(metadata i32 undef, metadata !60, metadata !DIExpression()), !dbg !61
+  %call = tail call i32 @"?foo@@YAHH@Z"(i32 1) #1, !dbg !62
+  %call1 = tail call i32 @"?foo2@@YAHH@Z"(i32 2) #1, !dbg !62
+  %mul = mul nsw i32 %call1, %call, !dbg !62
+  %call2 = tail call i32 @"?foo2@@YAHH@Z"(i32 3) #1, !dbg !62
+  %mul3 = mul nsw i32 %mul, %call2, !dbg !62
+  ret i32 %mul3, !dbg !62
+}
+
+define dso_local i32 @main(i32 %argc, i8** nocapture readnone %argv) local_unnamed_addr #1 !dbg !63 !annotation !72 {
+entry:
+  call void @llvm.dbg.value(metadata i8** %argv, metadata !70, metadata !DIExpression()), !dbg !73
+  call void @llvm.dbg.value(metadata i32 %argc, metadata !71, metadata !DIExpression()), !dbg !73
+  %cmp = icmp eq i32 %argc, 2, !dbg !74
+  br i1 %cmp, label %return, label %if.end, !dbg !74
+
+if.end:                                           ; preds = %entry
+  %cmp1 = icmp slt i32 %argc, 5, !dbg !75
+  br i1 %cmp1, label %if.then2, label %if.else, !dbg !75
+
+if.then2:                                         ; preds = %if.end
+  %call = tail call i32 @"?bar@@YAHH@Z"(i32 undef) #1, !dbg !76
+  br label %return, !dbg !76
+
+if.else:                                          ; preds = %if.end
+  %call3 = tail call i32 @"?foo@@YAHH@Z"(i32 %argc) #1, !dbg !79
+  br label %return, !dbg !79
+
+return:                                           ; preds = %entry, %if.else, %if.then2
+  %retval.0 = phi i32 [ %call, %if.then2 ], [ %call3, %if.else ], [ 0, %entry ], !dbg !73
+  ret i32 %retval.0, !dbg !81
+}
+
+declare void @llvm.dbg.value(metadata, metadata, metadata) #3
+
+attributes #1 = { optsize }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!5, !6, !7, !8, !9, !38}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 13.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "pgo.cpp", directory: "")
+!2 = !{}
+!5 = !{i32 2, !"CodeView", i32 1}
+!6 = !{i32 2, !"Debug Info Version", i32 3}
+!7 = !{i32 1, !"wchar_size", i32 2}
+!8 = !{i32 7, !"PIC Level", i32 2}
+!9 = !{i32 1, !"ProfileSummary", !10}
+!10 = !{!11, !12, !13, !14, !15, !16, !17, !18, !19, !20}
+!11 = !{!"ProfileFormat", !"InstrProf"}
+!12 = !{!"TotalCount", i64 2}
+!13 = !{!"MaxCount", i64 1}
+!14 = !{!"MaxInternalCount", i64 1}
+!15 = !{!"MaxFunctionCount", i64 1}
+!16 = !{!"NumCounts", i64 5}
+!17 = !{!"NumFunctions", i64 4}
+!18 = !{!"IsPartialProfile", i64 0}
+!19 = !{!"PartialProfileRatio", double 0.000000e+00}
+!20 = !{!"DetailedSummary", !21}
+!21 = !{!22, !23, !24, !25, !26, !27, !28, !29, !30, !31, !32, !33, !34, !35, !36, !37}
+!22 = !{i32 10000, i64 0, i32 0}
+!23 = !{i32 100000, i64 0, i32 0}
+!24 = !{i32 200000, i64 0, i32 0}
+!25 = !{i32 300000, i64 0, i32 0}
+!26 = !{i32 400000, i64 0, i32 0}
+!27 = !{i32 500000, i64 1, i32 2}
+!28 = !{i32 600000, i64 1, i32 2}
+!29 = !{i32 700000, i64 1, i32 2}
+!30 = !{i32 800000, i64 1, i32 2}
+!31 = !{i32 900000, i64 1, i32 2}
+!32 = !{i32 950000, i64 1, i32 2}
+!33 = !{i32 990000, i64 1, i32 2}
+!34 = !{i32 999000, i64 1, i32 2}
+!35 = !{i32 999900, i64 1, i32 2}
+!36 = !{i32 999990, i64 1, i32 2}
+!37 = !{i32 999999, i64 1, i32 2}
+!38 = !{i32 5, !"CG Profile", !39}
+!39 = !{!40, !41}
+!40 = !{i32 (i32)* @"?bar@@YAHH@Z", i32 (i32)* @"?foo@@YAHH@Z", i64 0}
+!41 = !{i32 (i32)* @"?bar@@YAHH@Z", i32 (i32)* @"?foo2@@YAHH@Z", i64 0}
+!43 = distinct !DISubprogram(name: "foo", linkageName: "?foo@@YAHH@Z", scope: !1, file: !1, line: 2, type: !44, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !47)
+!44 = !DISubroutineType(types: !45)
+!45 = !{!46, !46}
+!46 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!47 = !{!48}
+!48 = !DILocalVariable(name: "b", arg: 1, scope: !43, file: !1, line: 2, type: !46)
+!49 = !{!"function_entry_count", i64 1}
+!50 = !DILocation(line: 0, scope: !43)
+!51 = !DILocation(line: 3, scope: !43)
+!52 = distinct !DISubprogram(name: "foo2", linkageName: "?foo2@@YAHH@Z", scope: !1, file: !1, line: 5, type: !44, scopeLine: 5, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !53)
+!53 = !{!54}
+!54 = !DILocalVariable(name: "a", arg: 1, scope: !52, file: !1, line: 5, type: !46)
+!55 = !{!"function_entry_count", i64 0}
+!56 = !DILocation(line: 0, scope: !52)
+!57 = !DILocation(line: 6, scope: !52)
+!58 = distinct !DISubprogram(name: "bar", linkageName: "?bar@@YAHH@Z", scope: !1, file: !1, line: 8, type: !44, scopeLine: 8, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !59)
+!59 = !{!60}
+!60 = !DILocalVariable(name: "num", arg: 1, scope: !58, file: !1, line: 8, type: !46)
+!61 = !DILocation(line: 0, scope: !58)
+!62 = !DILocation(line: 9, scope: !58)
+!63 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 11, type: !64, scopeLine: 12, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !69)
+!64 = !DISubroutineType(types: !65)
+!65 = !{!46, !46, !66}
+!66 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !67, size: 64)
+!67 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !68, size: 64)
+!68 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
+!69 = !{!70, !71}
+!70 = !DILocalVariable(name: "argv", arg: 2, scope: !63, file: !1, line: 11, type: !66)
+!71 = !DILocalVariable(name: "argc", arg: 1, scope: !63, file: !1, line: 11, type: !46)
+!72 = !{!"instr_prof_hash_mismatch"}
+!73 = !DILocation(line: 0, scope: !63)
+!74 = !DILocation(line: 13, scope: !63)
+!75 = !DILocation(line: 16, scope: !63)
+!76 = !DILocation(line: 17, scope: !77)
+!77 = distinct !DILexicalBlock(scope: !78, file: !1, line: 16)
+!78 = distinct !DILexicalBlock(scope: !63, file: !1, line: 16)
+!79 = !DILocation(line: 19, scope: !80)
+!80 = distinct !DILexicalBlock(scope: !78, file: !1, line: 18)
+!81 = !DILocation(line: 21, scope: !63)