[DebugInfoMetadata] Move main subprogram DIFlag into DISPFlags

Moving subprogram specific flags into DISPFlags makes IR code more readable. In addition, we provide free space in DIFlags for other 'non-subprogram-specific' debug info flags. Patch by Djordje Todorovic. Differential Revision: https://reviews.llvm.org/D59288 llvm-svn: 356454
llvm · Mar 19, 2019 · 38a6187 · 38a6187
1 parent 423b958
commit 38a6187
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Showing 11 changed files with 64 additions and 18 deletions.
diff --git a/llvm/include/llvm-c/DebugInfo.h b/llvm/include/llvm-c/DebugInfo.h
@@ -50,7 +50,6 @@ typedef enum {
   LLVMDIFlagIntroducedVirtual = 1 << 18,
   LLVMDIFlagBitField = 1 << 19,
   LLVMDIFlagNoReturn = 1 << 20,
-  LLVMDIFlagMainSubprogram = 1 << 21,
   LLVMDIFlagTypePassByValue = 1 << 22,
   LLVMDIFlagTypePassByReference = 1 << 23,
   LLVMDIFlagEnumClass = 1 << 24,

diff --git a/llvm/include/llvm/IR/DebugInfoFlags.def b/llvm/include/llvm/IR/DebugInfoFlags.def
@@ -50,7 +50,6 @@ HANDLE_DI_FLAG((3 << 16), VirtualInheritance)
 HANDLE_DI_FLAG((1 << 18), IntroducedVirtual)
 HANDLE_DI_FLAG((1 << 19), BitField)
 HANDLE_DI_FLAG((1 << 20), NoReturn)
-HANDLE_DI_FLAG((1 << 21), MainSubprogram)
 HANDLE_DI_FLAG((1 << 22), TypePassByValue)
 HANDLE_DI_FLAG((1 << 23), TypePassByReference)
 HANDLE_DI_FLAG((1 << 24), EnumClass)
@@ -88,11 +87,12 @@ HANDLE_DISP_FLAG((1u << 4), Optimized)
 HANDLE_DISP_FLAG((1u << 5), Pure)
 HANDLE_DISP_FLAG((1u << 6), Elemental)
 HANDLE_DISP_FLAG((1u << 7), Recursive)
+HANDLE_DISP_FLAG((1u << 8), MainSubprogram)
 
 #ifdef DISP_FLAG_LARGEST_NEEDED
 // Intended to be used with ADT/BitmaskEnum.h.
 // NOTE: Always must be equal to largest flag, check this when adding new flags.
-HANDLE_DISP_FLAG((1 << 7), Largest)
+HANDLE_DISP_FLAG((1 << 8), Largest)
 #undef DISP_FLAG_LARGEST_NEEDED
 #endif
 

diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -1675,7 +1675,8 @@ class DISubprogram : public DILocalScope {
   // Helper for converting old bitfields to new flags word.
   static DISPFlags toSPFlags(bool IsLocalToUnit, bool IsDefinition,
                              bool IsOptimized,
-                             unsigned Virtuality = SPFlagNonvirtual) {
+                             unsigned Virtuality = SPFlagNonvirtual,
+                             bool IsMainSubprogram = false) {
     // We're assuming virtuality is the low-order field.
     static_assert(
         int(SPFlagVirtual) == int(dwarf::DW_VIRTUALITY_virtual) &&
@@ -1685,7 +1686,8 @@ class DISubprogram : public DILocalScope {
         (Virtuality & SPFlagVirtuality) |
         (IsLocalToUnit ? SPFlagLocalToUnit : SPFlagZero) |
         (IsDefinition ? SPFlagDefinition : SPFlagZero) |
-        (IsOptimized ? SPFlagOptimized : SPFlagZero));
+        (IsOptimized ? SPFlagOptimized : SPFlagZero) |
+        (IsMainSubprogram ? SPFlagMainSubprogram : SPFlagZero));
   }
 
 private:
@@ -1784,6 +1786,7 @@ class DISubprogram : public DILocalScope {
   bool isLocalToUnit() const { return getSPFlags() & SPFlagLocalToUnit; }
   bool isDefinition() const { return getSPFlags() & SPFlagDefinition; }
   bool isOptimized() const { return getSPFlags() & SPFlagOptimized; }
+  bool isMainSubprogram() const { return getSPFlags() & SPFlagMainSubprogram; }
 
   bool isArtificial() const { return getFlags() & FlagArtificial; }
   bool isPrivate() const {
@@ -1800,7 +1803,6 @@ class DISubprogram : public DILocalScope {
   bool areAllCallsDescribed() const {
     return getFlags() & FlagAllCallsDescribed;
   }
-  bool isMainSubprogram() const { return getFlags() & FlagMainSubprogram; }
   bool isPure() const { return getSPFlags() & SPFlagPure; }
   bool isElemental() const { return getSPFlags() & SPFlagElemental; }
   bool isRecursive() const { return getSPFlags() & SPFlagRecursive; }

diff --git a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
@@ -1406,12 +1406,33 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
       return error("Invalid record");
 
     bool HasSPFlags = Record[0] & 4;
-    DISubprogram::DISPFlags SPFlags =
-        HasSPFlags
-            ? static_cast<DISubprogram::DISPFlags>(Record[9])
-            : DISubprogram::toSPFlags(
-                  /*IsLocalToUnit=*/Record[7], /*IsDefinition=*/Record[8],
-                  /*IsOptimized=*/Record[14], /*Virtuality=*/Record[11]);
+
+    DINode::DIFlags Flags;
+    DISubprogram::DISPFlags SPFlags;
+    if (!HasSPFlags)
+      Flags = static_cast<DINode::DIFlags>(Record[11 + 2]);
+    else {
+      Flags = static_cast<DINode::DIFlags>(Record[11]);
+      SPFlags = static_cast<DISubprogram::DISPFlags>(Record[9]);
+    }
+
+    // Support for old metadata when
+    // subprogram specific flags are placed in DIFlags.
+    const unsigned DIFlagMainSubprogram = 1 << 21;
+    bool HasOldMainSubprogramFlag = Flags & DIFlagMainSubprogram;
+    if (HasOldMainSubprogramFlag)
+      // Remove old DIFlagMainSubprogram from DIFlags.
+      // Note: This assumes that any future use of bit 21 defaults to it
+      // being 0.
+      Flags &= ~static_cast<DINode::DIFlags>(DIFlagMainSubprogram);
+
+    if (HasOldMainSubprogramFlag && HasSPFlags)
+      SPFlags |= DISubprogram::SPFlagMainSubprogram;
+    else if (!HasSPFlags)
+      SPFlags = DISubprogram::toSPFlags(
+                    /*IsLocalToUnit=*/Record[7], /*IsDefinition=*/Record[8],
+                    /*IsOptimized=*/Record[14], /*Virtuality=*/Record[11],
+                    /*DIFlagMainSubprogram*/HasOldMainSubprogramFlag);
 
     // All definitions should be distinct.
     IsDistinct = (Record[0] & 1) || (SPFlags & DISubprogram::SPFlagDefinition);
@@ -1455,7 +1476,7 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
          getDITypeRefOrNull(Record[8 + OffsetA]),           // containingType
          Record[10 + OffsetA],                              // virtualIndex
          HasThisAdj ? Record[16 + OffsetB] : 0,             // thisAdjustment
-         static_cast<DINode::DIFlags>(Record[11 + OffsetA]),// flags
+         Flags,                                             // flags
          SPFlags,                                           // SPFlags
          HasUnit ? CUorFn : nullptr,                        // unit
          getMDOrNull(Record[13 + OffsetB]),                 // templateParams

diff --git a/llvm/test/Bitcode/DISubprogram-v5.ll b/llvm/test/Bitcode/DISubprogram-v5.ll
@@ -0,0 +1,24 @@
+ ; The .bc file was generated from this source using llvm-as from 8.0 release.
+ ; RUN: llvm-dis < %s.bc | FileCheck %s
+
+define i32 @main() !dbg !5 {
+entry:
+  %retval = alloca i32, align 4
+  store i32 0, i32* %retval
+  ret i32 0, !dbg !9
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 8.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
+!1 = !DIFile(filename: "mainsubprogram.c", directory: "/dir")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 1, !"Debug Info Version", i32 3}
+!5 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 6, type: !6, scopeLine: 6, virtualIndex: 6, flags: DIFlagPrototyped | DIFlagMainSubprogram, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+; CHECK: !5 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 6, type: !6, scopeLine: 6, virtualIndex: 6, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagMainSubprogram, unit: !0, retainedNodes: !2)
+!6 = !DISubroutineType(types: !7)
+!7 = !{!8}
+!8 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!9 = !DILocation(line: 7, scope: !5)
diff --git a/llvm/test/Bitcode/DISubprogram-v5.ll.bc b/llvm/test/Bitcode/DISubprogram-v5.ll.bc
diff --git a/llvm/test/DebugInfo/Generic/containing-type-extension.ll b/llvm/test/DebugInfo/Generic/containing-type-extension.ll
@@ -25,7 +25,7 @@ attributes #0 = { nounwind uwtable }
 !0 = distinct !DICompileUnit(language: DW_LANG_Rust, producer: "clang version 3.4 (trunk 185475)", isOptimized: false, emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !2, globals: !15, imports: !2)
 !1 = !DIFile(filename: "CodeGen/dwarf-version.c", directory: "test")
 !2 = !{}
-!4 = distinct !DISubprogram(name: "main", line: 6, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped | DIFlagMainSubprogram, isOptimized: false, unit: !0, scopeLine: 6, file: !1, scope: !5, type: !6, retainedNodes: !2)
+!4 = distinct !DISubprogram(name: "main", line: 6, virtualIndex: 6, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagMainSubprogram, isOptimized: false, unit: !0, scopeLine: 6, file: !1, scope: !5, type: !6, retainedNodes: !2)
 !5 = !DIFile(filename: "CodeGen/dwarf-version.c", directory: "test")
 !6 = !DISubroutineType(types: !7)
 !7 = !{!8}

diff --git a/llvm/test/DebugInfo/Generic/discriminated-union.ll b/llvm/test/DebugInfo/Generic/discriminated-union.ll
@@ -53,7 +53,7 @@ attributes #0 = { nounwind uwtable }
 !2 = distinct !DICompileUnit(language: DW_LANG_Rust, file: !3, producer: "clang LLVM (rustc version 1.24.0-dev)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4)
 !3 = !DIFile(filename: "e3.rs", directory: "/home/tromey/Rust")
 !4 = !{}
-!5 = distinct !DISubprogram(name: "main", linkageName: "_ZN2e34mainE", scope: !6, file: !3, line: 2, type: !8, isLocal: true, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped | DIFlagMainSubprogram, isOptimized: false, unit: !2, templateParams: !4, retainedNodes: !4)
+!5 = distinct !DISubprogram(name: "main", linkageName: "_ZN2e34mainE", scope: !6, file: !3, line: 2, type: !8, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagMainSubprogram, isOptimized: false, unit: !2, templateParams: !4, retainedNodes: !4)
 !6 = !DINamespace(name: "e3", scope: null)
 !7 = !DIFile(filename: "<unknown>", directory: "")
 !8 = !DISubroutineType(types: !9)

diff --git a/llvm/test/DebugInfo/Generic/mainsubprogram.ll b/llvm/test/DebugInfo/Generic/mainsubprogram.ll
@@ -25,7 +25,7 @@ attributes #0 = { nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointe
 !0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.4 (trunk 185475)", isOptimized: false, emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
 !1 = !DIFile(filename: "CodeGen/dwarf-version.c", directory: "test")
 !2 = !{}
-!4 = distinct !DISubprogram(name: "main", line: 6, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped | DIFlagMainSubprogram, isOptimized: false, unit: !0, scopeLine: 6, file: !1, scope: !5, type: !6, retainedNodes: !2)
+!4 = distinct !DISubprogram(name: "main", line: 6, virtualIndex: 6, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagMainSubprogram, isOptimized: false, unit: !0, scopeLine: 6, file: !1, scope: !5, type: !6, retainedNodes: !2)
 !5 = !DIFile(filename: "CodeGen/dwarf-version.c", directory: "test")
 !6 = !DISubroutineType(types: !7)
 !7 = !{!8}

diff --git a/llvm/test/DebugInfo/Generic/univariant-discriminated-union.ll b/llvm/test/DebugInfo/Generic/univariant-discriminated-union.ll
@@ -40,7 +40,7 @@ attributes #0 = { nounwind uwtable }
 !2 = distinct !DICompileUnit(language: DW_LANG_Rust, file: !3, producer: "clang LLVM (rustc version 1.24.0-dev)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4)
 !3 = !DIFile(filename: "e3.rs", directory: "/home/tromey/Rust")
 !4 = !{}
-!5 = distinct !DISubprogram(name: "main", linkageName: "_ZN2e34mainE", scope: !6, file: !3, line: 2, type: !8, isLocal: true, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped | DIFlagMainSubprogram, isOptimized: false, unit: !2, templateParams: !4, retainedNodes: !4)
+!5 = distinct !DISubprogram(name: "main", linkageName: "_ZN2e34mainE", scope: !6, file: !3, line: 2, type: !8, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagMainSubprogram, isOptimized: false, unit: !2, templateParams: !4, retainedNodes: !4)
 !6 = !DINamespace(name: "e3", scope: null)
 !7 = !DIFile(filename: "<unknown>", directory: "")
 !8 = !DISubroutineType(types: !9)

diff --git a/llvm/test/DebugInfo/X86/containing-type-extension-rust.ll b/llvm/test/DebugInfo/X86/containing-type-extension-rust.ll
@@ -109,7 +109,7 @@ attributes #3 = { "no-frame-pointer-elim"="true" "probe-stack"="__rust_probestac
 !22 = !DIExpression()
 !23 = !DILocation(line: 1, scope: !11)
 !24 = !DILocation(line: 59, scope: !11)
-!25 = distinct !DISubprogram(name: "main", linkageName: "_ZN2t24mainE", scope: !26, file: !9, line: 9, type: !27, isLocal: true, isDefinition: true, scopeLine: 9, flags: DIFlagPrototyped | DIFlagMainSubprogram, isOptimized: false, unit: !8, templateParams: !4, retainedNodes: !4)
+!25 = distinct !DISubprogram(name: "main", linkageName: "_ZN2t24mainE", scope: !26, file: !9, line: 9, type: !27, scopeLine: 9, flags: DIFlagPrototyped, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagMainSubprogram, isOptimized: false, unit: !8, templateParams: !4, retainedNodes: !4)
 !26 = !DINamespace(name: "t2", scope: null)
 !27 = !DISubroutineType(types: !28)
 !28 = !{null}