[llvm-dwarfdump][Statistics] Count more than one concrete out-of-line instance of a function

[krisb]

Summary

Here may be more than one out-of-line instance of the same function among different CUs. All of them should be accounted for to get an accurate total number of variables/parameters.

[aprantl]

Test case update?

[krisb]

Added a test.

[krisb]

@aprantl thanks for the review! Are you okay with this test?

[aprantl]

thanks!

llvm/test/tools/llvm-dwarfdump/X86/stats-mulitple-cu-out-of-line.ll

+; RUN: llc -O0 %s -o - -filetype=obj \
+; RUN:   | llvm-dwarfdump -statistics - | FileCheck %s
+
+; Test checks that statistics accounts two and more out-of-line instances
+; of a function and reports the correct number of variables.
+
+; $ cat test.h
+;
+; int foo(int a) { return a; }
+;
+; $ cat test1.cpp
+;
+; #include "test.h"
+; int bar() { return foo(42); }
+;
+; $ cat test2.cpp
+;
+; #include "test.h"
+; int far() { return foo(42); }
+
+; CHECK:      "source functions":3
+; CHECK-SAME: "source functions with location":3
+; CHECK-SAME: "inlined functions":0
+; CHECK-SAME: "unique source variables":1
+; CHECK-SAME: "source variables":2
+; CHECK-SAME: "variables with location":2
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local i32 @_Z3fooi.1(i32 %a) !dbg !9 {
+entry:
+  %a.addr = alloca i32, align 4
+  store i32 %a, i32* %a.addr, align 4
+  call void @llvm.dbg.declare(metadata i32* %a.addr, metadata !14, metadata !DIExpression()), !dbg !15
+  %0 = load i32, i32* %a.addr, align 4, !dbg !15
+  ret i32 %0, !dbg !15
+}
+; Function Attrs: nounwind readnone speculatable willreturn
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local i32 @_Z3barv() !dbg !18 {
+entry:
+  %call = call i32 @_Z3fooi.1(i32 42), !dbg !21
+  ret i32 %call, !dbg !21
+}
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local i32 @_Z3fooi(i32 %a) !dbg !23 {
+entry:
+  %a.addr = alloca i32, align 4
+  store i32 %a, i32* %a.addr, align 4
+  call void @llvm.dbg.declare(metadata i32* %a.addr, metadata !24, metadata !DIExpression()), !dbg !25
+  %0 = load i32, i32* %a.addr, align 4, !dbg !25
+  ret i32 %0, !dbg !25
+}
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local i32 @_Z3farv() !dbg !28 {
+entry:
+  %call = call i32 @_Z3fooi(i32 42), !dbg !29
+  ret i32 %call, !dbg !29
+}
+
+!llvm.dbg.cu = !{!0, !3}
+!llvm.ident = !{!5, !5}
+!llvm.module.flags = !{!6, !7, !8}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 11.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "test1.cpp", directory: "/")
+!2 = !{}
+!3 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !4, producer: "clang version 11.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None)
+!4 = !DIFile(filename: "test2.cpp", directory: "/")
+!5 = !{!"clang version 11.0.0"}
+!6 = !{i32 7, !"Dwarf Version", i32 4}
+!7 = !{i32 2, !"Debug Info Version", i32 3}
+!8 = !{i32 1, !"wchar_size", i32 4}
+!9 = distinct !DISubprogram(name: "foo", linkageName: "_Z3fooi", scope: !10, file: !10, line: 1, type: !11, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!10 = !DIFile(filename: "./test.h", directory: "/")
+!11 = !DISubroutineType(types: !12)
+!12 = !{!13, !13}
+!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!14 = !DILocalVariable(name: "a", arg: 1, scope: !9, file: !10, line: 1, type: !13)
+!15 = !DILocation(line: 1, column: 13, scope: !9)
+!18 = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv", scope: !1, file: !1, line: 3, type: !19, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!19 = !DISubroutineType(types: !20)
+!20 = !{!13}
+!21 = !DILocation(line: 3, column: 20, scope: !18)
+!23 = distinct !DISubprogram(name: "foo", linkageName: "_Z3fooi", scope: !10, file: !10, line: 1, type: !11, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !3, retainedNodes: !2)
+!24 = !DILocalVariable(name: "a", arg: 1, scope: !23, file: !10, line: 1, type: !13)
+!25 = !DILocation(line: 1, column: 13, scope: !23)
+!28 = distinct !DISubprogram(name: "far", linkageName: "_Z3farv", scope: !4, file: !4, line: 3, type: !19, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !3, retainedNodes: !2)
+!29 = !DILocation(line: 3, column: 20, scope: !28)

llvm/tools/llvm-dwarfdump/Statistics.cpp

 /// location coverage.
 constexpr int NumOfCoverageCategories = 12;
 
 /// Holds statistics for one function (or other entity that has a PC range and
 /// contains variables, such as a compile unit).
 struct PerFunctionStats {
   /// Number of inlined instances of this function.
   unsigned NumFnInlined = 0;
+  /// Number of out-of-line instances of this function.
+  unsigned NumFnOutOfLine = 0;
   /// Number of inlined instances that have abstract origins.
   unsigned NumAbstractOrigins = 0;
   /// Number of variables and parameters with location across all inlined
   /// instances.
   unsigned TotalVarWithLoc = 0;
   /// Number of constants with location across all inlined instances.
   unsigned ConstantMembers = 0;
   /// List of all Variables and parameters in this function.
   StringSet<> VarsInFunction;
   /// Compile units also cover a PC range, but have this flag set to false.
   bool IsFunction = false;
-  /// Verify function definition has PC addresses (for detecting when
-  /// a function has been inlined everywhere).
-  bool HasPCAddresses = false;
   /// Function has source location information.
   bool HasSourceLocation = false;
   /// Number of function parameters.
   unsigned NumParams = 0;
   /// Number of function parameters with source location.
   unsigned NumParamSourceLocations = 0;
   /// Number of function parameters with type.
   unsigned NumParamTypes = 0;
for (auto Range : Ranges)
       BytesInThisScope += Range.HighPC - Range.LowPC;
 
     // Count the function.
     if (!IsBlock) {
       // Skip over abstract origins.
       if (Die.find(dwarf::DW_AT_inline))
         return;
       std::string FnID = constructDieID(Die);
-      // We've seen an (inlined) instance of this function.
+      // We've seen an instance of this function.
       auto &FnStats = FnStatMap[FnID];
       FnStats.IsFunction = true;
       if (IsInlinedFunction) {
         FnStats.NumFnInlined++;
         if (Die.findRecursively(dwarf::DW_AT_abstract_origin))
           FnStats.NumAbstractOrigins++;
+      } else {
+        FnStats.NumFnOutOfLine++;
       }
-      if (BytesInThisScope && !IsInlinedFunction)
-        FnStats.HasPCAddresses = true;
       if (Die.findRecursively(dwarf::DW_AT_decl_file) &&
           Die.findRecursively(dwarf::DW_AT_decl_line))
         FnStats.HasSourceLocation = true;
       // Update function prefix.
       FnPrefix = FnID;
     }
 
     if (BytesInThisScope) {
bool collectStatsForObjectFile(ObjectFile &Obj, DWARFContext &DICtx,
   unsigned ParamWithLoc = 0;
   unsigned ParamWithSrcLoc = 0;
   unsigned VarTotal = 0;
   unsigned VarWithType = 0;
   unsigned VarWithSrcLoc = 0;
   unsigned VarWithLoc = 0;
   for (auto &Entry : Statistics) {
     PerFunctionStats &Stats = Entry.getValue();
-    unsigned TotalVars = Stats.VarsInFunction.size() * Stats.NumFnInlined;
-    // Count variables in concrete out-of-line functions and in global scope.
-    if (Stats.HasPCAddresses || !Stats.IsFunction)
+    unsigned TotalVars = Stats.VarsInFunction.size() *
+                         (Stats.NumFnInlined + Stats.NumFnOutOfLine);
+    // Count variables in global scope.
+    if (!Stats.IsFunction)
       TotalVars += Stats.VarsInFunction.size();
     unsigned Constants = Stats.ConstantMembers;
     VarParamWithLoc += Stats.TotalVarWithLoc + Constants;
     VarParamTotal += TotalVars;
     VarParamUnique += Stats.VarsInFunction.size();
     LLVM_DEBUG(for (auto &V
                     : Stats.VarsInFunction) llvm::dbgs()
                << Entry.getKey() << ": " << V.getKey() << "\n");