[DEBUGINFO] Disable emission of the dwarf sections, but allow directives.

Summary:
Added an option that allows to emit only '.loc' and '.file' kind debug
directives, but disables emission of the DWARF sections. Required for
NVPTX target to support profiling. It requires '.loc' and '.file'
directives, but does not require any DWARF sections for the profiler.

Reviewers: probinson, echristo, dblaikie

Subscribers: aprantl, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D46021

llvm-svn: 338616

diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
index 8207468..905a7ca 100644 (file)
--- a/llvm/include/llvm/IR/DebugInfoMetadata.h
+++ b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -1162,7 +1162,8 @@ public:
     NoDebug = 0,
     FullDebug,
     LineTablesOnly,
-    LastEmissionKind = LineTablesOnly
+    DebugDirectivesOnly,
+    LastEmissionKind = DebugDirectivesOnly
   };
 
   static Optional<DebugEmissionKind> getEmissionKind(StringRef Str);
@@ -1268,6 +1269,9 @@ public:
   DebugEmissionKind getEmissionKind() const {
     return (DebugEmissionKind)EmissionKind;
   }
+  bool isDebugDirectivesOnly() const {
+    return EmissionKind == DebugDirectivesOnly;
+  }
   bool getDebugInfoForProfiling() const { return DebugInfoForProfiling; }
   bool getGnuPubnames() const { return GnuPubnames; }
   StringRef getProducer() const { return getStringOperand(1); }

diff --git a/llvm/lib/AsmParser/LLLexer.cpp b/llvm/lib/AsmParser/LLLexer.cpp
index da9855f..437579a 100644 (file)
--- a/llvm/lib/AsmParser/LLLexer.cpp
+++ b/llvm/lib/AsmParser/LLLexer.cpp
@@ -905,7 +905,7 @@ lltok::Kind LLLexer::LexIdentifier() {
   }
 
   if (Keyword == "NoDebug" || Keyword == "FullDebug" ||
-      Keyword == "LineTablesOnly") {
+      Keyword == "LineTablesOnly" || Keyword == "DebugDirectivesOnly") {
     StrVal.assign(Keyword.begin(), Keyword.end());
     return lltok::EmissionKind;
   }

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 32271a0..5b47237 100644 (file)
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -275,6 +275,9 @@ void DwarfCompileUnit::addRange(RangeSpan Range) {
 }
 
 void DwarfCompileUnit::initStmtList() {
+  if (CUNode->isDebugDirectivesOnly())
+    return;
+
   // Define start line table label for each Compile Unit.
   MCSymbol *LineTableStartSym;
   const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
@@ -882,7 +885,7 @@ bool DwarfCompileUnit::hasDwarfPubSections() const {
     return true;
 
   return DD->tuneForGDB() && DD->usePubSections() &&
-         !includeMinimalInlineScopes();
+         !includeMinimalInlineScopes() && !CUNode->isDebugDirectivesOnly();
 }
 
 /// addGlobalName - Add a new global name to the compile unit.

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 500e7a0..549bf74 100644 (file)
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -768,6 +768,8 @@ void DwarfDebug::finalizeModuleInfo() {
   // all other generation.
   for (const auto &P : CUMap) {
     auto &TheCU = *P.second;
+    if (TheCU.getCUNode()->isDebugDirectivesOnly())
+      continue;
     // Emit DW_AT_containing_type attribute to connect types with their
     // vtable holding type.
     TheCU.constructContainingTypeDIEs();
@@ -1416,6 +1418,11 @@ void DwarfDebug::endFunctionImpl(const MachineFunction *MF) {
   LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
   assert(!FnScope || SP == FnScope->getScopeNode());
   DwarfCompileUnit &TheCU = *CUMap.lookup(SP->getUnit());
+  if (TheCU.getCUNode()->isDebugDirectivesOnly()) {
+    PrevLabel = nullptr;
+    CurFn = nullptr;
+    return;
+  }
 
   DenseSet<InlinedVariable> ProcessedVars;
   collectVariableInfo(TheCU, SP, ProcessedVars);
@@ -2132,6 +2139,13 @@ void DwarfDebug::emitDebugRanges() {
         });
   };
 
+  if (llvm::all_of(CUMap, [](const decltype(CUMap)::value_type &Pair) {
+        return Pair.second->getCUNode()->isDebugDirectivesOnly();
+      })) {
+    assert(NoRangesPresent() && "No debug ranges expected.");
+    return;
+  }
+
   if (!useRangesSection()) {
     assert(NoRangesPresent() && "No debug ranges expected.");
     return;
@@ -2154,6 +2168,8 @@ void DwarfDebug::emitDebugRanges() {
   // Grab the specific ranges for the compile units in the module.
   for (const auto &I : CUMap) {
     DwarfCompileUnit *TheCU = I.second;
+    if (TheCU->getCUNode()->isDebugDirectivesOnly())
+      continue;
 
     if (auto *Skel = TheCU->getSkeleton())
       TheCU = Skel;
@@ -2206,12 +2222,19 @@ void DwarfDebug::emitDebugMacinfo() {
   if (CUMap.empty())
     return;
 
+  if (llvm::all_of(CUMap, [](const decltype(CUMap)::value_type &Pair) {
+        return Pair.second->getCUNode()->isDebugDirectivesOnly();
+      }))
+    return;
+
   // Start the dwarf macinfo section.
   Asm->OutStreamer->SwitchSection(
       Asm->getObjFileLowering().getDwarfMacinfoSection());
 
   for (const auto &P : CUMap) {
     auto &TheCU = *P.second;
+    if (TheCU.getCUNode()->isDebugDirectivesOnly())
+      continue;
     auto *SkCU = TheCU.getSkeleton();
     DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;
     auto *CUNode = cast<DICompileUnit>(P.first);

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp
index 049f349..96149fd 100644 (file)
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp
@@ -36,6 +36,9 @@ void DwarfFile::emitUnits(bool UseOffsets) {
 }
 
 void DwarfFile::emitUnit(DwarfUnit *TheU, bool UseOffsets) {
+  if (TheU->getCUNode()->isDebugDirectivesOnly())
+    return;
+
   DIE &Die = TheU->getUnitDie();
   MCSection *USection = TheU->getSection();
   Asm->OutStreamer->SwitchSection(USection);
@@ -53,6 +56,9 @@ void DwarfFile::computeSizeAndOffsets() {
   // Iterate over each compile unit and set the size and offsets for each
   // DIE within each compile unit. All offsets are CU relative.
   for (const auto &TheU : CUs) {
+    if (TheU->getCUNode()->isDebugDirectivesOnly())
+      continue;
+
     TheU->setDebugSectionOffset(SecOffset);
     SecOffset += computeSizeAndOffsetsForUnit(TheU.get());
   }

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index 600f4a7..df67c5f 100644 (file)
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -234,6 +234,9 @@ void DwarfUnit::addSInt(DIELoc &Die, Optional<dwarf::Form> Form,
 
 void DwarfUnit::addString(DIE &Die, dwarf::Attribute Attribute,
                           StringRef String) {
+  if (CUNode->isDebugDirectivesOnly())
+    return;
+
   if (DD->useInlineStrings()) {
     Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_string,
                  new (DIEValueAllocator)

diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index 910e8c2..7908b25 100644 (file)
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -472,6 +472,7 @@ DICompileUnit::getEmissionKind(StringRef Str) {
       .Case("NoDebug", NoDebug)
       .Case("FullDebug", FullDebug)
       .Case("LineTablesOnly", LineTablesOnly)
+      .Case("DebugDirectivesOnly", DebugDirectivesOnly)
       .Default(None);
 }
 
@@ -480,6 +481,7 @@ const char *DICompileUnit::emissionKindString(DebugEmissionKind EK) {
   case NoDebug:        return "NoDebug";
   case FullDebug:      return "FullDebug";
   case LineTablesOnly: return "LineTablesOnly";
+  case DebugDirectivesOnly: return "DebugDirectviesOnly";
   }
   return nullptr;
 }

diff --git a/llvm/test/DebugInfo/Generic/directives-only.ll b/llvm/test/DebugInfo/Generic/directives-only.ll
new file mode 100644 (file)
index 0000000..484fa33
--- /dev/null
+++ b/llvm/test/DebugInfo/Generic/directives-only.ll
@@ -0,0 +1,59 @@
+; RUN: llc -filetype=asm -asm-verbose=0 -O0 < %s | FileCheck %s
+
+; Generated with clang from multiline.c:
+; void f1();
+; void f2() {
+;   f1(); f1(); f1();
+;   f1(); f1(); f1();
+; }
+
+
+; CHECK: .file 1 "/tmp/dbginfo{{.*}}multiline.c"
+; CHECK: .loc 1 2 0
+; CHECK: .loc 1 3 3
+; CHECK: .loc 1 3 9
+; CHECK: .loc 1 3 15
+; CHECK: .loc 1 4 3
+; CHECK: .loc 1 4 9
+; CHECK: .loc 1 4 15
+; CHECK: .loc 1 5 1
+
+; CHECK-NOT: .section .{{debug.*}}
+
+; Function Attrs: nounwind uwtable
+define void @f2() #0 !dbg !4 {
+entry:
+  call void (...) @f1(), !dbg !11
+  call void (...) @f1(), !dbg !12
+  call void (...) @f1(), !dbg !13
+  call void (...) @f1(), !dbg !14
+  call void (...) @f1(), !dbg !15
+  call void (...) @f1(), !dbg !16
+  ret void, !dbg !17
+}
+
+declare void @f1(...) #1
+
+attributes #0 = { nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!8, !9}
+!llvm.ident = !{!10}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.6.0 (trunk 225000) (llvm/trunk 224999)", isOptimized: false, emissionKind: DebugDirectivesOnly, file: !1)
+!1 = !DIFile(filename: "multiline.c", directory: "/tmp/dbginfo")
+!4 = distinct !DISubprogram(name: "f2", line: 2, isLocal: false, isDefinition: true, isOptimized: false, unit: !0, scopeLine: 2, file: !1, scope: !5, type: !6)
+!5 = !DIFile(filename: "multiline.c", directory: "/tmp/dbginfo")
+!6 = !DISubroutineType(types: !7)
+!7 = !{null}
+!8 = !{i32 2, !"Dwarf Version", i32 4}
+!9 = !{i32 2, !"Debug Info Version", i32 3}
+!10 = !{!"clang version 3.6.0 (trunk 225000) (llvm/trunk 224999)"}
+!11 = !DILocation(line: 3, column: 3, scope: !4)
+!12 = !DILocation(line: 3, column: 9, scope: !4)
+!13 = !DILocation(line: 3, column: 15, scope: !4)
+!14 = !DILocation(line: 4, column: 3, scope: !4)
+!15 = !DILocation(line: 4, column: 9, scope: !4)
+!16 = !DILocation(line: 4, column: 15, scope: !4)
+!17 = !DILocation(line: 5, column: 1, scope: !4)