Index: llvm/trunk/docs/CommandGuide/llvm-dwarfdump.rst
===================================================================
--- llvm/trunk/docs/CommandGuide/llvm-dwarfdump.rst
+++ llvm/trunk/docs/CommandGuide/llvm-dwarfdump.rst
@@ -84,6 +84,11 @@
Only recurse to a maximum depth of <n> when dumping debug info
entries.
+.. option:: --statistics
+
+ Collect debug info quality metrics and print the results
+ as machine-readable single-line JSON output.
+
.. option:: -x, --regex
Treat any <pattern> strings as regular expressions when searching
Index: llvm/trunk/include/llvm/ADT/STLExtras.h
===================================================================
--- llvm/trunk/include/llvm/ADT/STLExtras.h
+++ llvm/trunk/include/llvm/ADT/STLExtras.h
@@ -902,6 +902,13 @@
return std::partition(std::begin(Range), std::end(Range), P);
}
+/// Provide wrappers to std::lower_bound which take ranges instead of having to
+/// pass begin/end explicitly.
+template <typename R, typename ForwardIt>
+auto lower_bound(R &&Range, ForwardIt I) -> decltype(std::begin(Range)) {
+ return std::lower_bound(std::begin(Range), std::end(Range), I);
+}
+
/// \brief Given a range of type R, iterate the entire range and return a
/// SmallVector with elements of the vector. This is useful, for example,
/// when you want to iterate a range and then sort the results.
Index: llvm/trunk/test/tools/llvm-dwarfdump/X86/statistics.ll
===================================================================
--- llvm/trunk/test/tools/llvm-dwarfdump/X86/statistics.ll
+++ llvm/trunk/test/tools/llvm-dwarfdump/X86/statistics.ll
@@ -0,0 +1,134 @@
+; RUN: llc -O0 %s -o - -filetype=obj \
+; RUN: | llvm-dwarfdump -statistics - | FileCheck %s
+
+; int GlobalConst = 42;
+; int Global;
+;
+; struct S {
+; static const int constant = 24;
+; } s;
+;
+; int __attribute__((always_inline)) square(int i) { return i * i; }
+; int cube(int i) {
+; int squared = square(i);
+; return squared*i;
+; }
+
+; GlobalConst,Global,s,s.constant,square::i,cube::i,cube::squared
+; CHECK: "unique source variables":7
+; +1 extra inline i.
+; CHECK: "source variables":8
+; -1 square::i
+; CHECK: "variables with location":7
+; CHECK: "scope bytes total":[[BYTES:[0-9]+]]
+; Because of the dbg.value in the middle of the function, the pc range coverage
+; must be below 100%.
+; CHECK-NOT: "scope bytes covered":0
+; CHECK-NOT "scope bytes covered":[[BYTES]]
+; CHECK: "scope bytes covered":
+
+; ModuleID = '/tmp/quality.cpp'
+source_filename = "/tmp/quality.cpp"
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.12.0"
+
+%struct.S = type { i8 }
+
+@GlobalConst = global i32 42, align 4, !dbg !0
+@Global = global i32 0, align 4, !dbg !6
+@s = global %struct.S zeroinitializer, align 1, !dbg !9
+
+; Function Attrs: alwaysinline nounwind ssp uwtable
+define i32 @_Z6squarei(i32 %i) #0 !dbg !20 {
+entry:
+ %i.addr = alloca i32, align 4
+ store i32 %i, i32* %i.addr, align 4
+ ; Modified to loose debug info for i here.
+ call void @llvm.dbg.declare(metadata i32* undef, metadata !23, metadata !24), !dbg !25
+ %0 = load i32, i32* %i.addr, align 4, !dbg !26
+ %1 = load i32, i32* %i.addr, align 4, !dbg !27
+ %mul = mul nsw i32 %0, %1, !dbg !28
+ ret i32 %mul, !dbg !29
+}
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+declare void @llvm.dbg.value(metadata, metadata, metadata) #1
+
+; Function Attrs: noinline nounwind optnone ssp uwtable
+define i32 @_Z4cubei(i32 %i) #2 !dbg !30 {
+entry:
+ %i.addr.i = alloca i32, align 4
+ call void @llvm.dbg.declare(metadata i32* %i.addr.i, metadata !23, metadata !24), !dbg !31
+ %i.addr = alloca i32, align 4
+ %squared = alloca i32, align 4
+ store i32 %i, i32* %i.addr, align 4
+ call void @llvm.dbg.declare(metadata i32* %i.addr, metadata !33, metadata !24), !dbg !34
+ %0 = load i32, i32* %i.addr, align 4, !dbg !37
+ store i32 %0, i32* %i.addr.i, align 4
+ %1 = load i32, i32* %i.addr.i, align 4, !dbg !38
+ %2 = load i32, i32* %i.addr.i, align 4, !dbg !39
+ %mul.i = mul nsw i32 %1, %2, !dbg !40
+ ; Modified to cover only about 50% of the lexical scope.
+ call void @llvm.dbg.value(metadata i32 %mul.i, metadata !35, metadata !24), !dbg !36
+ store i32 %mul.i, i32* %squared, align 4, !dbg !36
+ %3 = load i32, i32* %squared, align 4, !dbg !41
+ call void @llvm.dbg.value(metadata i32 %3, metadata !35, metadata !24), !dbg !36
+ %4 = load i32, i32* %i.addr, align 4, !dbg !42
+ %mul = mul nsw i32 %3, %4, !dbg !43
+ ret i32 %mul, !dbg !44
+}
+
+attributes #0 = { alwaysinline nounwind ssp uwtable }
+attributes #1 = { nounwind readnone speculatable }
+attributes #2 = { noinline nounwind optnone ssp uwtable }
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!15, !16, !17, !18}
+!llvm.ident = !{!19}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "GlobalConst", scope: !2, file: !3, line: 1, type: !8, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 6.0.0 (trunk 310529) (llvm/trunk 310534)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
+!3 = !DIFile(filename: "/tmp/quality.cpp", directory: "/Volumes/Data/llvm")
+!4 = !{}
+!5 = !{!0, !6, !9}
+!6 = !DIGlobalVariableExpression(var: !7, expr: !DIExpression())
+!7 = distinct !DIGlobalVariable(name: "Global", scope: !2, file: !3, line: 2, type: !8, isLocal: false, isDefinition: true)
+!8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!9 = !DIGlobalVariableExpression(var: !10, expr: !DIExpression())
+!10 = distinct !DIGlobalVariable(name: "s", scope: !2, file: !3, line: 6, type: !11, isLocal: false, isDefinition: true)
+!11 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "S", file: !3, line: 4, size: 8, elements: !12, identifier: "_ZTS1S")
+!12 = !{!13}
+!13 = !DIDerivedType(tag: DW_TAG_member, name: "constant", scope: !11, file: !3, line: 5, baseType: !14, flags: DIFlagStaticMember, extraData: i32 24)
+!14 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !8)
+!15 = !{i32 2, !"Dwarf Version", i32 4}
+!16 = !{i32 2, !"Debug Info Version", i32 3}
+!17 = !{i32 1, !"wchar_size", i32 4}
+!18 = !{i32 7, !"PIC Level", i32 2}
+!19 = !{!"clang version 6.0.0 (trunk 310529) (llvm/trunk 310534)"}
+!20 = distinct !DISubprogram(name: "square", linkageName: "_Z6squarei", scope: !3, file: !3, line: 8, type: !21, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !2, variables: !4)
+!21 = !DISubroutineType(types: !22)
+!22 = !{!8, !8}
+!23 = !DILocalVariable(name: "i", arg: 1, scope: !20, file: !3, line: 8, type: !8)
+!24 = !DIExpression()
+!25 = !DILocation(line: 8, column: 47, scope: !20)
+!26 = !DILocation(line: 8, column: 59, scope: !20)
+!27 = !DILocation(line: 8, column: 63, scope: !20)
+!28 = !DILocation(line: 8, column: 61, scope: !20)
+!29 = !DILocation(line: 8, column: 52, scope: !20)
+!30 = distinct !DISubprogram(name: "cube", linkageName: "_Z4cubei", scope: !3, file: !3, line: 9, type: !21, isLocal: false, isDefinition: true, scopeLine: 9, flags: DIFlagPrototyped, isOptimized: false, unit: !2, variables: !4)
+!31 = !DILocation(line: 8, column: 47, scope: !20, inlinedAt: !32)
+!32 = distinct !DILocation(line: 10, column: 17, scope: !30)
+!33 = !DILocalVariable(name: "i", arg: 1, scope: !30, file: !3, line: 9, type: !8)
+!34 = !DILocation(line: 9, column: 14, scope: !30)
+!35 = !DILocalVariable(name: "squared", scope: !30, file: !3, line: 10, type: !8)
+!36 = !DILocation(line: 10, column: 7, scope: !30)
+!37 = !DILocation(line: 10, column: 24, scope: !30)
+!38 = !DILocation(line: 8, column: 59, scope: !20, inlinedAt: !32)
+!39 = !DILocation(line: 8, column: 63, scope: !20, inlinedAt: !32)
+!40 = !DILocation(line: 8, column: 61, scope: !20, inlinedAt: !32)
+!41 = !DILocation(line: 11, column: 10, scope: !30)
+!42 = !DILocation(line: 11, column: 18, scope: !30)
+!43 = !DILocation(line: 11, column: 17, scope: !30)
+!44 = !DILocation(line: 11, column: 3, scope: !30)
Index: llvm/trunk/test/tools/llvm-dwarfdump/cmdline.test
===================================================================
--- llvm/trunk/test/tools/llvm-dwarfdump/cmdline.test
+++ llvm/trunk/test/tools/llvm-dwarfdump/cmdline.test
@@ -14,6 +14,7 @@
HELP: -show-children
HELP: -show-form
HELP: -show-parents
+HELP: -statistics
HELP: -summarize-types
HELP-NOT: -reverse-iterate
Index: llvm/trunk/tools/llvm-dwarfdump/CMakeLists.txt
===================================================================
--- llvm/trunk/tools/llvm-dwarfdump/CMakeLists.txt
+++ llvm/trunk/tools/llvm-dwarfdump/CMakeLists.txt
@@ -8,6 +8,7 @@
)
add_llvm_tool(llvm-dwarfdump
+ Statistics.cpp
llvm-dwarfdump.cpp
)
Index: llvm/trunk/tools/llvm-dwarfdump/Statistics.cpp
===================================================================
--- llvm/trunk/tools/llvm-dwarfdump/Statistics.cpp
+++ llvm/trunk/tools/llvm-dwarfdump/Statistics.cpp
@@ -0,0 +1,239 @@
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/DebugInfo/DIContext.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h"
+#include "llvm/Object/ObjectFile.h"
+
+#define DEBUG_TYPE "dwarfdump"
+using namespace llvm;
+using namespace object;
+
+/// 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 variables 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 in this function.
+ SmallDenseSet<uint32_t, 4> VarsInFunction;
+ /// Compile units also cover a PC range, but have this flag set to false.
+ bool IsFunction = false;
+};
+
+/// Holds accumulated global statistics about local variables.
+struct GlobalStats {
+ /// Total number of PC range bytes covered by DW_AT_locations.
+ unsigned ScopeBytesCovered = 0;
+ /// Total number of PC range bytes in each variable's enclosing scope,
+ /// starting from the first definition of the variable.
+ unsigned ScopeBytesFromFirstDefinition = 0;
+};
+
+/// Extract the low pc from a Die.
+static uint64_t getLowPC(DWARFDie Die) {
+ if (Die.getAddressRanges().size())
+ return Die.getAddressRanges()[0].LowPC;
+ return dwarf::toAddress(Die.find(dwarf::DW_AT_low_pc), 0);
+}
+
+/// Collect debug info quality metrics for one DIE.
+static void collectStatsForDie(DWARFDie Die, std::string Prefix,
+ uint64_t ScopeLowPC, uint64_t BytesInScope,
+ StringMap<PerFunctionStats> &FnStatMap,
+ GlobalStats &GlobalStats) {
+ bool HasLoc = false;
+ uint64_t BytesCovered = 0;
+ uint64_t OffsetToFirstDefinition = 0;
+ if (Die.find(dwarf::DW_AT_const_value)) {
+ // This catches constant members *and* variables.
+ HasLoc = true;
+ BytesCovered = BytesInScope;
+ } else if (Die.getTag() == dwarf::DW_TAG_variable ||
+ Die.getTag() == dwarf::DW_TAG_formal_parameter) {
+ // Handle variables and function arguments.
+ auto FormValue = Die.find(dwarf::DW_AT_location);
+ HasLoc = FormValue.hasValue();
+ if (HasLoc) {
+ // Get PC coverage.
+ if (auto DebugLocOffset = FormValue->getAsSectionOffset()) {
+ auto *DebugLoc = Die.getDwarfUnit()->getContext().getDebugLoc();
+ if (auto List = DebugLoc->getLocationListAtOffset(*DebugLocOffset)) {
+ for (auto Entry : List->Entries)
+ BytesCovered += Entry.End - Entry.Begin;
+ if (List->Entries.size()) {
+ uint64_t FirstDef = List->Entries[0].Begin;
+ uint64_t UnitOfs = getLowPC(Die.getDwarfUnit()->getUnitDIE());
+ // Ranges sometimes start before the lexical scope.
+ if (UnitOfs + FirstDef >= ScopeLowPC)
+ OffsetToFirstDefinition = UnitOfs + FirstDef - ScopeLowPC;
+ // Or even after it. Count that as a failure.
+ if (OffsetToFirstDefinition > BytesInScope)
+ OffsetToFirstDefinition = 0;
+ }
+ }
+ assert(BytesInScope);
+ } else {
+ // Assume the entire range is covered by a single location.
+ BytesCovered = BytesInScope;
+ }
+ }
+ } else {
+ // Not a variable or constant member.
+ return;
+ }
+
+ // Collect PC range coverage data.
+ auto &FnStats = FnStatMap[Prefix];
+ if (DWARFDie D =
+ Die.getAttributeValueAsReferencedDie(dwarf::DW_AT_abstract_origin))
+ Die = D;
+ // This is a unique ID for the variable inside the current object file.
+ unsigned CanonicalDieOffset = Die.getOffset();
+ FnStats.VarsInFunction.insert(CanonicalDieOffset);
+ if (BytesInScope) {
+ FnStats.TotalVarWithLoc += (unsigned)HasLoc;
+ // Adjust for the fact the variables often start their lifetime in the
+ // middle of the scope.
+ BytesInScope -= OffsetToFirstDefinition;
+ // Turns out we have a lot of ranges that extend past the lexical scope.
+ GlobalStats.ScopeBytesCovered += std::min(BytesInScope, BytesCovered);
+ GlobalStats.ScopeBytesFromFirstDefinition += BytesInScope;
+ assert(GlobalStats.ScopeBytesCovered <=
+ GlobalStats.ScopeBytesFromFirstDefinition);
+ } else {
+ FnStats.ConstantMembers++;
+ }
+}
+
+/// Recursively collect debug info quality metrics.
+static void collectStatsRecursive(DWARFDie Die, std::string Prefix,
+ uint64_t ScopeLowPC, uint64_t BytesInScope,
+ StringMap<PerFunctionStats> &FnStatMap,
+ GlobalStats &GlobalStats) {
+ // Handle any kind of lexical scope.
+ if (Die.getTag() == dwarf::DW_TAG_subprogram ||
+ Die.getTag() == dwarf::DW_TAG_inlined_subroutine ||
+ Die.getTag() == dwarf::DW_TAG_lexical_block) {
+ // Ignore forward declarations.
+ if (Die.find(dwarf::DW_AT_declaration))
+ return;
+
+ // Count the function.
+ if (Die.getTag() != dwarf::DW_TAG_lexical_block) {
+ StringRef Name = Die.getName(DINameKind::LinkageName);
+ if (Name.empty())
+ Name = Die.getName(DINameKind::ShortName);
+ Prefix = Name;
+ // Skip over abstract origins.
+ if (Die.find(dwarf::DW_AT_inline))
+ return;
+ // We've seen an (inlined) instance of this function.
+ auto &FnStats = FnStatMap[Name];
+ FnStats.NumFnInlined++;
+ FnStats.IsFunction = true;
+ }
+
+ // PC Ranges.
+ auto Ranges = Die.getAddressRanges();
+ uint64_t BytesInThisScope = 0;
+ for (auto Range : Ranges)
+ BytesInThisScope += Range.HighPC - Range.LowPC;
+ ScopeLowPC = getLowPC(Die);
+
+ if (BytesInThisScope)
+ BytesInScope = BytesInThisScope;
+ } else {
+ // Not a scope, visit the Die itself. It could be a variable.
+ collectStatsForDie(Die, Prefix, ScopeLowPC, BytesInScope, FnStatMap,
+ GlobalStats);
+ }
+
+ // Traverse children.
+ DWARFDie Child = Die.getFirstChild();
+ while (Child) {
+ collectStatsRecursive(Child, Prefix, ScopeLowPC, BytesInScope, FnStatMap,
+ GlobalStats);
+ Child = Child.getSibling();
+ }
+}
+
+/// Print machine-readable output.
+/// The machine-readable format is single-line JSON output.
+/// \{
+static void printDatum(raw_ostream &OS, const char *Key, StringRef Value) {
+ OS << ",\"" << Key << "\":\"" << Value << '"';
+ DEBUG(llvm::dbgs() << Key << ": " << Value << '\n');
+}
+static void printDatum(raw_ostream &OS, const char *Key, uint64_t Value) {
+ OS << ",\"" << Key << "\":" << Value;
+ DEBUG(llvm::dbgs() << Key << ": " << Value << '\n');
+}
+/// \}
+
+/// Collect debug info quality metrics for an entire DIContext.
+///
+/// Do the impossible and reduce the quality of the debug info down to a few
+/// numbers. The idea is to condense the data into numbers that can be tracked
+/// over time to identify trends in newer compiler versions and gauge the effect
+/// of particular optimizations. The raw numbers themselves are not particularly
+/// useful, only the delta between compiling the same program with different
+/// compilers is.
+bool collectStatsForObjectFile(ObjectFile &Obj, DWARFContext &DICtx,
+ Twine Filename, raw_ostream &OS) {
+ StringRef FormatName = Obj.getFileFormatName();
+ GlobalStats GlobalStats;
+ StringMap<PerFunctionStats> Statistics;
+ for (const auto &CU : static_cast<DWARFContext *>(&DICtx)->compile_units())
+ if (DWARFDie CUDie = CU->getUnitDIE(false))
+ collectStatsRecursive(CUDie, "/", 0, 0, Statistics, GlobalStats);
+
+ /// The version number should be increased every time the algorithm is changed
+ /// (including bug fixes). New metrics may be added without increasing the
+ /// version.
+ unsigned Version = 1;
+ unsigned VarTotal = 0;
+ unsigned VarUnique = 0;
+ unsigned VarWithLoc = 0;
+ unsigned NumFunctions = 0;
+ unsigned NumInlinedFunctions = 0;
+ for (auto &Entry : Statistics) {
+ PerFunctionStats &Stats = Entry.getValue();
+ unsigned TotalVars = Stats.VarsInFunction.size() * Stats.NumFnInlined;
+ unsigned Constants = Stats.ConstantMembers;
+ VarWithLoc += Stats.TotalVarWithLoc + Constants;
+ VarTotal += TotalVars + Constants;
+ VarUnique += Stats.VarsInFunction.size();
+ DEBUG(for (auto V : Stats.VarsInFunction)
+ llvm::dbgs() << Entry.getKey() << ": " << V << "\n");
+ NumFunctions += Stats.IsFunction;
+ NumInlinedFunctions += Stats.IsFunction * Stats.NumFnInlined;
+ }
+
+ // Print summary.
+ OS.SetBufferSize(1024);
+ OS << "{\"version\":\"" << Version << '"';
+ DEBUG(llvm::dbgs() << "Variable location quality metrics\n";
+ llvm::dbgs() << "---------------------------------\n");
+ printDatum(OS, "file", Filename.str());
+ printDatum(OS, "format", FormatName);
+ printDatum(OS, "source functions", NumFunctions);
+ printDatum(OS, "inlined functions", NumInlinedFunctions);
+ printDatum(OS, "unique source variables", VarUnique);
+ printDatum(OS, "source variables", VarTotal);
+ printDatum(OS, "variables with location", VarWithLoc);
+ printDatum(OS, "scope bytes total",
+ GlobalStats.ScopeBytesFromFirstDefinition);
+ printDatum(OS, "scope bytes covered", GlobalStats.ScopeBytesCovered);
+ OS << "}\n";
+ DEBUG(
+ llvm::dbgs() << "Total Availability: "
+ << (int)std::round((VarWithLoc * 100.0) / VarTotal) << "%\n";
+ llvm::dbgs() << "PC Ranges covered: "
+ << (int)std::round((GlobalStats.ScopeBytesCovered * 100.0) /
+ GlobalStats.ScopeBytesFromFirstDefinition)
+ << "%\n");
+ return true;
+}
Index: llvm/trunk/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
===================================================================
--- llvm/trunk/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
+++ llvm/trunk/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
@@ -201,6 +201,10 @@
SummarizeTypes("summarize-types",
desc("Abbreviate the description of type unit entries"),
cat(DwarfDumpCategory));
+static cl::opt<bool>
+ Statistics("statistics",
+ cl::desc("Emit JSON-formatted debug info quality metrics."),
+ cat(DwarfDumpCategory));
static opt<bool> Verify("verify", desc("Verify the DWARF debug info"),
cat(DwarfDumpCategory));
static opt<bool> Quiet("quiet", desc("Use with -verify to not emit to STDOUT."),
@@ -301,6 +305,9 @@
}
}
+bool collectStatsForObjectFile(ObjectFile &Obj, DWARFContext &DICtx,
+ Twine Filename, raw_ostream &OS);
+
static bool dumpObjectFile(ObjectFile &Obj, DWARFContext &DICtx, Twine Filename,
raw_ostream &OS) {
logAllUnhandledErrors(DICtx.loadRegisterInfo(Obj), errs(),
@@ -536,7 +543,10 @@
return handleFile(Object, verifyObjectFile, OS);
}))
exit(1);
- } else
+ } else if (Statistics)
+ for (auto Object : Objects)
+ handleFile(Object, collectStatsForObjectFile, OS);
+ else
for (auto Object : Objects)
handleFile(Object, dumpObjectFile, OS);