DWARF Type Units: Avoid emitting type units under fission if the type requires an...

Since there's no way to ensure the type unit in the .dwo and the type
unit skeleton in the .o are correlated, this cannot work.

This implementation is a bit inefficient for a few reasons, called out
in comments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207323 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/AsmPrinter/AddressPool.cpp b/lib/CodeGen/AsmPrinter/AddressPool.cpp
index 222717b81b1bab7b4415327c5c26f2011092cefa..8dab5e59d6323654a3f258309648da8ea6cf0d96 100644 (file)
--- a/lib/CodeGen/AsmPrinter/AddressPool.cpp
+++ b/lib/CodeGen/AsmPrinter/AddressPool.cpp
@@ -17,6 +17,7 @@ using namespace llvm;
 class MCExpr;
 
 unsigned AddressPool::getIndex(const MCSymbol *Sym, bool TLS) {
+  HasBeenUsed = true;
   auto IterBool =
       Pool.insert(std::make_pair(Sym, AddressPoolEntry(Pool.size(), TLS)));
   return IterBool.first->second.Number;

diff --git a/lib/CodeGen/AsmPrinter/AddressPool.h b/lib/CodeGen/AsmPrinter/AddressPool.h
index d0c9b0d857758f11de5f50362748bdf748996cf3..3058fed33fd08941212327c916d2298345def1a9 100644 (file)
--- a/lib/CodeGen/AsmPrinter/AddressPool.h
+++ b/lib/CodeGen/AsmPrinter/AddressPool.h
@@ -26,8 +26,11 @@ class AddressPool {
     AddressPoolEntry(unsigned Number, bool TLS) : Number(Number), TLS(TLS) {}
   };
   DenseMap<const MCSymbol *, AddressPoolEntry> Pool;
+  bool HasBeenUsed;
 
 public:
+  AddressPool() : HasBeenUsed(false) {}
+
   /// \brief Returns the index into the address pool with the given
   /// label/symbol.
   unsigned getIndex(const MCSymbol *Sym, bool TLS = false);
@@ -35,6 +38,10 @@ public:
   void emit(AsmPrinter &Asm, const MCSection *AddrSection);
 
   bool isEmpty() { return Pool.empty(); }
+
+  bool hasBeenUsed() const { return HasBeenUsed; }
+
+  void resetUsedFlag() { HasBeenUsed = false; }
 };
 }
 #endif

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index cbd2eb6ca4435f9850d8a850832a15748088ad74..0465b8929a72c64e8e2b6251de2e554958dd1e59 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -2500,19 +2500,28 @@ static uint64_t makeTypeSignature(StringRef Identifier) {
 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
                                       StringRef Identifier, DIE &RefDie,
                                       DICompositeType CTy) {
+  // Fast path if we're building some type units and one has already used the
+  // address pool we know we're going to throw away all this work anyway, so
+  // don't bother building dependent types.
+  if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
+    return;
+
   const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
   if (TU) {
     CU.addDIETypeSignature(RefDie, *TU);
     return;
   }
 
+  bool TopLevelType = TypeUnitsUnderConstruction.empty();
+  AddrPool.resetUsedFlag();
+
   DIE *UnitDie = new DIE(dwarf::DW_TAG_type_unit);
   auto OwnedUnit =
       make_unique<DwarfTypeUnit>(InfoHolder.getUnits().size(), UnitDie, CU, Asm,
                                  this, &InfoHolder, getDwoLineTable(CU));
   DwarfTypeUnit &NewTU = *OwnedUnit;
   TU = &NewTU;
-  InfoHolder.addUnit(std::move(OwnedUnit));
+  TypeUnitsUnderConstruction.push_back(std::make_pair(std::move(OwnedUnit), CTy));
 
   NewTU.addUInt(*UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
                 CU.getLanguage());
@@ -2520,9 +2529,7 @@ void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
   uint64_t Signature = makeTypeSignature(Identifier);
   NewTU.setTypeSignature(Signature);
 
-  if (useSplitDwarf())
-    NewTU.setSkeleton(constructSkeletonTU(NewTU));
-  else
+  if (!useSplitDwarf())
     CU.applyStmtList(*UnitDie);
 
   NewTU.initSection(
@@ -2532,6 +2539,36 @@ void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
 
   NewTU.setType(NewTU.createTypeDIE(CTy));
 
+  if (TopLevelType) {
+    auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
+    TypeUnitsUnderConstruction.clear();
+
+    // Types referencing entries in the address table cannot be placed in type
+    // units.
+    if (AddrPool.hasBeenUsed()) {
+
+      // Remove all the types built while building this type.
+      // This is pessimistic as some of these types might not be dependent on
+      // the type that used an address.
+      for (const auto &TU : TypeUnitsToAdd)
+        DwarfTypeUnits.erase(TU.second);
+
+      // Construct this type in the CU directly.
+      // This is inefficient because all the dependent types will be rebuilt
+      // from scratch, including building them in type units, discovering that
+      // they depend on addresses, throwing them out and rebuilding them.
+      CU.constructTypeDIE(RefDie, CTy);
+      return;
+    }
+
+    // If the type wasn't dependent on fission addresses, finish adding the type
+    // and all its dependent types.
+    for (auto &TU : TypeUnitsToAdd) {
+      if (useSplitDwarf())
+        TU.first->setSkeleton(constructSkeletonTU(*TU.first));
+      InfoHolder.addUnit(std::move(TU.first));
+    }
+  }
   CU.addDIETypeSignature(RefDie, NewTU);
 }
 

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 9038c648af340bfccc695f448c45b424ef05ec0e..a5bbb251229063aede3c71929ab5ced7b02fce5e 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -284,6 +284,8 @@ class DwarfDebug : public AsmPrinterHandler {
   // them.
   DenseMap<const MDNode *, const DwarfTypeUnit *> DwarfTypeUnits;
 
+  SmallVector<std::pair<std::unique_ptr<DwarfTypeUnit>, DICompositeType>, 1> TypeUnitsUnderConstruction;
+
   // Whether to emit the pubnames/pubtypes sections.
   bool HasDwarfPubSections;
 

diff --git a/lib/CodeGen/AsmPrinter/DwarfUnit.h b/lib/CodeGen/AsmPrinter/DwarfUnit.h
index 1e64f58fe0d3604691658c25874d9d1307786b00..69774f551be158c4dc5e0dec4c2887fd59da4294 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DwarfUnit.h
+++ b/lib/CodeGen/AsmPrinter/DwarfUnit.h
@@ -445,6 +445,9 @@ public:
 
   virtual DwarfCompileUnit &getCU() = 0;
 
+  /// constructTypeDIE - Construct type DIE from DICompositeType.
+  void constructTypeDIE(DIE &Buffer, DICompositeType CTy);
+
 protected:
   /// getOrCreateStaticMemberDIE - Create new static data member DIE.
   DIE *getOrCreateStaticMemberDIE(DIDerivedType DT);
@@ -465,9 +468,6 @@ private:
   /// constructTypeDIE - Construct derived type die from DIDerivedType.
   void constructTypeDIE(DIE &Buffer, DIDerivedType DTy);
 
-  /// constructTypeDIE - Construct type DIE from DICompositeType.
-  void constructTypeDIE(DIE &Buffer, DICompositeType CTy);
-
   /// constructSubrangeDIE - Construct subrange DIE from DISubrange.
   void constructSubrangeDIE(DIE &Buffer, DISubrange SR, DIE *IndexTy);
 

diff --git a/test/DebugInfo/X86/type_units_with_addresses.ll b/test/DebugInfo/X86/type_units_with_addresses.ll
new file mode 100644 (file)
index 0000000..71a84ba
--- /dev/null
+++ b/test/DebugInfo/X86/type_units_with_addresses.ll
@@ -0,0 +1,109 @@
+; REQUIRES: object-emission
+
+; RUN: llc -split-dwarf=Enable -filetype=obj -O0 -generate-type-units -mtriple=x86_64-unknown-linux-gnu < %s \
+; RUN:     | llvm-dwarfdump - | FileCheck %s
+
+; RUN: llc -split-dwarf=Disable -filetype=obj -O0 -generate-type-units -mtriple=x86_64-unknown-linux-gnu < %s \
+; RUN:     | llvm-dwarfdump - | FileCheck --check-prefix=SINGLE %s
+
+; CHECK: .debug_info.dwo contents:
+
+; CHECK: DW_TAG_structure_type
+; CHECK-NEXT: DW_AT_name {{.*}}"S1<&i>"
+
+; CHECK: DW_TAG_structure_type
+; CHECK-NEXT: DW_AT_name {{.*}}"S2"
+; CHECK: DW_TAG_structure_type
+; CHECK-NEXT: DW_AT_name {{.*}}"S2_1<&i>"
+
+; CHECK: DW_TAG_structure_type
+; CHECK-NEXT: DW_AT_name {{.*}}"S3"
+; CHECK: DW_TAG_structure_type
+; CHECK-NEXT: DW_AT_name {{.*}}"S3_1<&i>"
+; CHECK: DW_TAG_structure_type
+; CHECK-NEXT: DW_AT_declaration
+; CHECK-NEXT: DW_AT_signature
+
+; CHECK: DW_TAG_structure_type
+; CHECK-NEXT: DW_AT_name {{.*}}"S4"
+; CHECK: DW_TAG_structure_type
+; CHECK-NEXT: DW_AT_declaration
+; CHECK-NEXT: DW_AT_signature
+; CHECK: DW_TAG_structure_type
+; CHECK-NEXT: DW_AT_name {{.*}}"S4_2<&i>"
+
+; SINGLE: .debug_info contents:
+
+; SINGLE: DW_TAG_structure_type
+; SINGLE-NEXT: DW_AT_declaration
+; SINGLE-NEXT: DW_AT_signature
+
+; SINGLE: DW_TAG_structure_type
+; SINGLE-NEXT: DW_AT_declaration
+; SINGLE-NEXT: DW_AT_signature
+
+; SINGLE: DW_TAG_structure_type
+; SINGLE-NEXT: DW_AT_declaration
+; SINGLE-NEXT: DW_AT_signature
+
+; SINGLE: DW_TAG_structure_type
+; SINGLE-NEXT: DW_AT_declaration
+; SINGLE-NEXT: DW_AT_signature
+
+%struct.S1 = type { i8 }
+%struct.S2 = type { %struct.S2_1 }
+%struct.S2_1 = type { i8 }
+%struct.S3 = type { %struct.S3_1, %struct.S3_2 }
+%struct.S3_1 = type { i8 }
+%struct.S3_2 = type { i8 }
+%struct.S4 = type { %struct.S4_1, %struct.S4_2 }
+%struct.S4_1 = type { i8 }
+%struct.S4_2 = type { i8 }
+
+@i = global i32 0, align 4
+@a = global %struct.S1 zeroinitializer, align 1
+@s2 = global %struct.S2 zeroinitializer, align 1
+@s3 = global %struct.S3 zeroinitializer, align 1
+@s4 = global %struct.S4 zeroinitializer, align 1
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!34, !35}
+!llvm.ident = !{!36}
+
+!0 = metadata !{i32 786449, metadata !1, i32 4, metadata !"clang version 3.5.0 ", i1 false, metadata !"", i32 0, metadata !2, metadata !3, metadata !2, metadata !27, metadata !2, metadata !"tu.dwo", i32 1} ; [ DW_TAG_compile_unit ] [/tmp/dbginfo/tu.cpp] [DW_LANG_C_plus_plus]
+!1 = metadata !{metadata !"tu.cpp", metadata !"/tmp/dbginfo"}
+!2 = metadata !{}
+!3 = metadata !{metadata !4, metadata !9, metadata !12, metadata !13, metadata !17, metadata !18, metadata !19, metadata !23, metadata !24}
+!4 = metadata !{i32 786451, metadata !1, null, metadata !"S1<&i>", i32 4, i64 8, i64 8, i32 0, i32 0, null, metadata !2, i32 0, null, metadata !5, metadata !"_ZTS2S1IXadL_Z1iEEE"} ; [ DW_TAG_structure_type ] [S1<&i>] [line 4, size 8, align 8, offset 0] [def] [from ]
+!5 = metadata !{metadata !6}
+!6 = metadata !{i32 786480, null, metadata !"I", metadata !7, i32* @i, null, i32 0, i32 0} ; [ DW_TAG_template_value_parameter ]
+!7 = metadata !{i32 786447, null, null, metadata !"", i32 0, i64 64, i64 64, i64 0, i32 0, metadata !8} ; [ DW_TAG_pointer_type ] [line 0, size 64, align 64, offset 0] [from int]
+!8 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
+!9 = metadata !{i32 786451, metadata !1, null, metadata !"S2", i32 11, i64 8, i64 8, i32 0, i32 0, null, metadata !10, i32 0, null, null, metadata !"_ZTS2S2"} ; [ DW_TAG_structure_type ] [S2] [line 11, size 8, align 8, offset 0] [def] [from ]
+!10 = metadata !{metadata !11}
+!11 = metadata !{i32 786445, metadata !1, metadata !"_ZTS2S2", metadata !"s2_1", i32 12, i64 8, i64 8, i64 0, i32 0, metadata !"_ZTS4S2_1IXadL_Z1iEEE"} ; [ DW_TAG_member ] [s2_1] [line 12, size 8, align 8, offset 0] [from _ZTS4S2_1IXadL_Z1iEEE]
+!12 = metadata !{i32 786451, metadata !1, null, metadata !"S2_1<&i>", i32 9, i64 8, i64 8, i32 0, i32 0, null, metadata !2, i32 0, null, metadata !5, metadata !"_ZTS4S2_1IXadL_Z1iEEE"} ; [ DW_TAG_structure_type ] [S2_1<&i>] [line 9, size 8, align 8, offset 0] [def] [from ]
+!13 = metadata !{i32 786451, metadata !1, null, metadata !"S3", i32 22, i64 16, i64 8, i32 0, i32 0, null, metadata !14, i32 0, null, null, metadata !"_ZTS2S3"} ; [ DW_TAG_structure_type ] [S3] [line 22, size 16, align 8, offset 0] [def] [from ]
+!14 = metadata !{metadata !15, metadata !16}
+!15 = metadata !{i32 786445, metadata !1, metadata !"_ZTS2S3", metadata !"s3_1", i32 23, i64 8, i64 8, i64 0, i32 0, metadata !"_ZTS4S3_1IXadL_Z1iEEE"} ; [ DW_TAG_member ] [s3_1] [line 23, size 8, align 8, offset 0] [from _ZTS4S3_1IXadL_Z1iEEE]
+!16 = metadata !{i32 786445, metadata !1, metadata !"_ZTS2S3", metadata !"s3_2", i32 24, i64 8, i64 8, i64 8, i32 0, metadata !"_ZTS4S3_2"} ; [ DW_TAG_member ] [s3_2] [line 24, size 8, align 8, offset 8] [from _ZTS4S3_2]
+!17 = metadata !{i32 786451, metadata !1, null, metadata !"S3_1<&i>", i32 18, i64 8, i64 8, i32 0, i32 0, null, metadata !2, i32 0, null, metadata !5, metadata !"_ZTS4S3_1IXadL_Z1iEEE"} ; [ DW_TAG_structure_type ] [S3_1<&i>] [line 18, size 8, align 8, offset 0] [def] [from ]
+!18 = metadata !{i32 786451, metadata !1, null, metadata !"S3_2", i32 20, i64 8, i64 8, i32 0, i32 0, null, metadata !2, i32 0, null, null, metadata !"_ZTS4S3_2"} ; [ DW_TAG_structure_type ] [S3_2] [line 20, size 8, align 8, offset 0] [def] [from ]
+!19 = metadata !{i32 786451, metadata !1, null, metadata !"S4", i32 34, i64 16, i64 8, i32 0, i32 0, null, metadata !20, i32 0, null, null, metadata !"_ZTS2S4"} ; [ DW_TAG_structure_type ] [S4] [line 34, size 16, align 8, offset 0] [def] [from ]
+!20 = metadata !{metadata !21, metadata !22}
+!21 = metadata !{i32 786445, metadata !1, metadata !"_ZTS2S4", metadata !"s4_1", i32 35, i64 8, i64 8, i64 0, i32 0, metadata !"_ZTS4S4_1"} ; [ DW_TAG_member ] [s4_1] [line 35, size 8, align 8, offset 0] [from _ZTS4S4_1]
+!22 = metadata !{i32 786445, metadata !1, metadata !"_ZTS2S4", metadata !"s4_2", i32 36, i64 8, i64 8, i64 8, i32 0, metadata !"_ZTS4S4_2IXadL_Z1iEEE"} ; [ DW_TAG_member ] [s4_2] [line 36, size 8, align 8, offset 8] [from _ZTS4S4_2IXadL_Z1iEEE]
+!23 = metadata !{i32 786451, metadata !1, null, metadata !"S4_1", i32 29, i64 8, i64 8, i32 0, i32 0, null, metadata !2, i32 0, null, null, metadata !"_ZTS4S4_1"} ; [ DW_TAG_structure_type ] [S4_1] [line 29, size 8, align 8, offset 0] [def] [from ]
+!24 = metadata !{i32 786451, metadata !1, null, metadata !"S4_2<&i>", i32 32, i64 8, i64 8, i32 0, i32 0, null, metadata !2, i32 0, null, metadata !25, metadata !"_ZTS4S4_2IXadL_Z1iEEE"} ; [ DW_TAG_structure_type ] [S4_2<&i>] [line 32, size 8, align 8, offset 0] [def] [from ]
+!25 = metadata !{metadata !26}
+!26 = metadata !{i32 786480, null, metadata !"T", metadata !7, i32* @i, null, i32 0, i32 0} ; [ DW_TAG_template_value_parameter ]
+!27 = metadata !{metadata !28, metadata !30, metadata !31, metadata !32, metadata !33}
+!28 = metadata !{i32 786484, i32 0, null, metadata !"i", metadata !"i", metadata !"", metadata !29, i32 1, metadata !8, i32 0, i32 1, i32* @i, null} ; [ DW_TAG_variable ] [i] [line 1] [def]
+!29 = metadata !{i32 786473, metadata !1}         ; [ DW_TAG_file_type ] [/tmp/dbginfo/tu.cpp]
+!30 = metadata !{i32 786484, i32 0, null, metadata !"a", metadata !"a", metadata !"", metadata !29, i32 6, metadata !"_ZTS2S1IXadL_Z1iEEE", i32 0, i32 1, %struct.S1* @a, null} ; [ DW_TAG_variable ] [a] [line 6] [def]
+!31 = metadata !{i32 786484, i32 0, null, metadata !"s2", metadata !"s2", metadata !"", metadata !29, i32 15, metadata !"_ZTS2S2", i32 0, i32 1, %struct.S2* @s2, null} ; [ DW_TAG_variable ] [s2] [line 15] [def]
+!32 = metadata !{i32 786484, i32 0, null, metadata !"s3", metadata !"s3", metadata !"", metadata !29, i32 27, metadata !"_ZTS2S3", i32 0, i32 1, %struct.S3* @s3, null} ; [ DW_TAG_variable ] [s3] [line 27] [def]
+!33 = metadata !{i32 786484, i32 0, null, metadata !"s4", metadata !"s4", metadata !"", metadata !29, i32 39, metadata !"_ZTS2S4", i32 0, i32 1, %struct.S4* @s4, null} ; [ DW_TAG_variable ] [s4] [line 39] [def]
+!34 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
+!35 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}
+!36 = metadata !{metadata !"clang version 3.5.0 "}