Merge pull request #6718 from rastogishubham/LineTableFix

rastogishubham · web-flow · commit 30f24ba954a3 · 2023-05-10T09:33:22.000-07:00
Fix cas-friendly line table emission in llvm
diff --git a/llvm/include/llvm/MC/MCDwarf.h b/llvm/include/llvm/MC/MCDwarf.h
@@ -230,7 +230,7 @@ class MCLineSection {
 
   // Add an end entry by cloning the last entry, if exists, for the section
   // the given EndLabel belongs to. The label is replaced by the given EndLabel.
-  void addEndEntry(MCSymbol *EndLabel);
+  void addEndEntry(MCSymbol *EndLabel, bool CasFriendlyDebugInfo = false);
 
   using MCDwarfLineEntryCollection = std::vector<MCDwarfLineEntry>;
   using iterator = MCDwarfLineEntryCollection::iterator;
diff --git a/llvm/include/llvm/MC/MCStreamer.h b/llvm/include/llvm/MC/MCStreamer.h
@@ -254,6 +254,9 @@ class MCStreamer {
   /// discussion for future inclusion.
   bool AllowAutoPadding = false;
 
+  /// Generate debug info that is Cas Friendly
+  bool GenerateCasFriendlyDebugInfo = false;
+
 protected:
   MCStreamer(MCContext &Ctx);
 
@@ -308,6 +311,13 @@ class MCStreamer {
   void setAllowAutoPadding(bool v) { AllowAutoPadding = v; }
   bool getAllowAutoPadding() const { return AllowAutoPadding; }
 
+  void setGenerateCasFriendlyDebugInfo(bool v) {
+    GenerateCasFriendlyDebugInfo = v;
+  }
+  bool getGenerateCasFriendlyDebugInfo() const {
+    return GenerateCasFriendlyDebugInfo;
+  }
+
   /// When emitting an object file, create and emit a real label. When emitting
   /// textual assembly, this should do nothing to avoid polluting our output.
   virtual MCSymbol *emitCFILabel();
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -464,7 +464,7 @@ DwarfDebug::DwarfDebug(AsmPrinter *A)
   Asm->OutStreamer->getContext().setDwarfFormat(Dwarf64 ? dwarf::DWARF64
                                                         : dwarf::DWARF32);
 
-  GenerateCasFriendlyDebugInfo = CasFriendlyDebugInfo;
+  Asm->OutStreamer->setGenerateCasFriendlyDebugInfo(CasFriendlyDebugInfo);
 }
 
 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
@@ -2233,7 +2233,8 @@ void DwarfDebug::terminateLineTable(const DwarfCompileUnit *CU) {
       getDwarfCompileUnitIDForLineTable(*CU));
   // Add the last range label for the given CU.
   LineTable.getMCLineSections().addEndEntry(
-      const_cast<MCSymbol *>(CURanges.back().End));
+      const_cast<MCSymbol *>(CURanges.back().End),
+      Asm->OutStreamer->getGenerateCasFriendlyDebugInfo());
 }
 
 void DwarfDebug::skippedNonDebugFunction() {
@@ -2329,7 +2330,7 @@ void DwarfDebug::endFunctionImpl(const MachineFunction *MF) {
   // we want to split up the line tables by function. To do this, we want to
   // emit a DW_LNE_end_sequence at the end of a function's contribution to the
   // line table.
-  if (GenerateCasFriendlyDebugInfo) {
+  if (Asm->OutStreamer->getGenerateCasFriendlyDebugInfo()) {
     MCSymbol *LineSym = Asm->OutStreamer->getContext().createTempSymbol();
     Asm->OutStreamer->emitLabel(LineSym);
     MCDwarfLoc DwarfLoc(
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -379,9 +379,6 @@ class DwarfDebug : public DebugHandlerBase {
   /// Avoid using DW_OP_convert due to consumer incompatibilities.
   bool EnableOpConvert;
 
-  /// Generate debug info that is Cas Friendly
-  bool GenerateCasFriendlyDebugInfo;
-
 public:
   enum class MinimizeAddrInV5 {
     Default,
diff --git a/llvm/lib/MC/MCDwarf.cpp b/llvm/lib/MC/MCDwarf.cpp
@@ -144,21 +144,26 @@ makeStartPlusIntExpr(MCContext &Ctx, const MCSymbol &Start, int IntVal) {
   return Res;
 }
 
-void MCLineSection::addEndEntry(MCSymbol *EndLabel) {
+void MCLineSection::addEndEntry(MCSymbol *EndLabel, bool CasFriendlyDebugInfo) {
   auto *Sec = &EndLabel->getSection();
   // The line table may be empty, which we should skip adding an end entry.
-  // There are two cases:
+  // There are three cases:
   // (1) MCAsmStreamer - emitDwarfLocDirective emits a location directive in
   //     place instead of adding a line entry if the target has
   //     usesDwarfFileAndLocDirectives.
   // (2) MCObjectStreamer - if a function has incomplete debug info where
   //     instructions don't have DILocations, the line entries are missing.
+  // (3) If the debug info is cas friendly, there is an end_sequence after every
+  // function and another one doesn't have to be emitted at the end of the line
+  // table.
   auto I = MCLineDivisions.find(Sec);
   if (I != MCLineDivisions.end()) {
     auto &Entries = I->second;
     auto EndEntry = Entries.back();
-    EndEntry.setEndLabel(EndLabel);
-    Entries.push_back(EndEntry);
+    if (!CasFriendlyDebugInfo) {
+      EndEntry.setEndLabel(EndLabel);
+      Entries.push_back(EndEntry);
+    }
   }
 }
 
@@ -173,7 +178,9 @@ void MCDwarfLineTable::emitOne(
   unsigned FileNum, LastLine, Column, Flags, Isa, Discriminator;
   MCSymbol *LastLabel;
   auto init = [&]() {
-    FileNum = 1;
+    // Force emission of DW_LNS_set_file for every function's contribution to
+    // the line table to maximize deduplication.
+    FileNum = MCOS->getGenerateCasFriendlyDebugInfo() ? 0 : 1;
     LastLine = 1;
     Column = 0;
     Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
@@ -188,29 +195,22 @@ void MCDwarfLineTable::emitOne(
   for (const MCDwarfLineEntry &LineEntry : LineEntries) {
     MCSymbol *Label = LineEntry.getLabel();
     const MCAsmInfo *asmInfo = MCOS->getContext().getAsmInfo();
-    if (LineEntry.IsEndEntry) {
+    if (LineEntry.IsEndEntry || LineEntry.IsEndOfFunction) {
       MCOS->emitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, Label,
                                      asmInfo->getCodePointerSize());
       init();
       EndEntryEmitted = true;
       continue;
     }
-    if (LineEntry.IsEndOfFunction) {
-      MCOS->emitInt8(char(dwarf::DW_LNS_extended_op));
-      MCOS->emitInt8(char(1));
-      MCOS->emitInt8(char(dwarf::DW_LNE_end_sequence));
-      init();
-      continue;
-    }
 
     int64_t LineDelta = static_cast<int64_t>(LineEntry.getLine()) - LastLine;
 
-    if (FileNum != LineEntry.getFileNum() || LineEntry.IsEndOfFunction) {
+    if (FileNum != LineEntry.getFileNum()) {
       FileNum = LineEntry.getFileNum();
       MCOS->emitInt8(dwarf::DW_LNS_set_file);
       MCOS->emitULEB128IntValue(FileNum);
     }
-    if (Column != LineEntry.getColumn() || LineEntry.IsEndOfFunction) {
+    if (Column != LineEntry.getColumn()) {
       Column = LineEntry.getColumn();
       MCOS->emitInt8(dwarf::DW_LNS_set_column);
       MCOS->emitULEB128IntValue(Column);
diff --git a/llvm/test/DebugInfo/CAS/AArch64/debug_line_and_info_dedupe.test b/llvm/test/DebugInfo/CAS/AArch64/debug_line_and_info_dedupe.test
@@ -11,8 +11,8 @@ CHECK-NEXT: DW_TAG_compile_unit
 CHECK: CAS Block: llvmcas://[[SUBPROGRAM_FOO:[a-z0-9]+]]
 CHECK-NEXT: DW_TAG_subprogram
 CHECK: mc:debug_line   llvmcas://
-CHECK-NEXT: mc:debug_line   llvmcas://
 CHECK-NEXT: mc:debug_line   llvmcas://[[LINETABLECASID:[a-z0-9]+]]
+CHECK-NEXT: mc:debug_line   llvmcas://
 
 
 CHECK: mc:assembler
@@ -22,79 +22,109 @@ CHECK: CAS Block: llvmcas://[[SUBPROGRAM_FOO]]
 CHECK-NEXT: DW_TAG_subprogram
 CHECK: mc:debug_line   llvmcas:// 
 CHECK-NEXT: mc:debug_line   llvmcas:// 
-CHECK-NEXT: mc:debug_line   llvmcas:// 
 CHECK-NEXT: mc:debug_line   llvmcas://[[LINETABLECASID]]
+CHECK-NEXT: mc:debug_line   llvmcas://
 
 //--- a.ll
 
-target triple = "arm64-apple-macosx12.0.0"
-define void @foo() #0 !dbg !9 {
-  ret void, !dbg !14
+; ModuleID = 'a.cpp'
+source_filename = "a.cpp"
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "arm64-apple-macosx13.0.0"
+
+; Function Attrs: noinline nounwind optnone ssp uwtable(sync)
+define i32 @_Z3foov() #0 !dbg !10 {
+  ret i32 3, !dbg !16
 }
-define void @bar(i32 noundef %x) #0 !dbg !15 {
-  ret void, !dbg !23
+
+; Function Attrs: noinline nounwind optnone ssp uwtable(sync)
+define i32 @_Z4foo2v() #0 !dbg !17 {
+  ret i32 4, !dbg !18
 }
-attributes #0 = { noinline nounwind optnone ssp uwtable "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="penryn" "target-features"="+cx16,+cx8,+fxsr,+mmx,+sahf,+sse,+sse2,+sse3,+sse4.1,+ssse3,+x87" "tune-cpu"="generic" }
-!llvm.dbg.cu = !{!0}
-!llvm.module.flags = !{!2, !3, !4, !5, !6, !7}
-!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 16.0.0 (https://github.com/apple/llvm-project.git d74d0d9fde90cccba7bf18066ac56e55e4402948)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None, sysroot: "/")
-!1 = !DIFile(filename: "a.c", directory: "/Users/shubham/Development/CASDelta")
-!2 = !{i32 7, !"Dwarf Version", i32 4}
-!3 = !{i32 2, !"Debug Info Version", i32 3}
-!4 = !{i32 1, !"wchar_size", i32 4}
-!5 = !{i32 7, !"PIC Level", i32 2}
-!6 = !{i32 7, !"uwtable", i32 2}
-!7 = !{i32 7, !"frame-pointer", i32 2}
-!9 = distinct !DISubprogram(name: "foo", scope: !10, file: !10, line: 1, type: !11, scopeLine: 1, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !13)
-!10 = !DIFile(filename: "./foo.h", directory: "/Users/shubham/Development/CASDelta")
-!11 = !DISubroutineType(types: !12)
-!12 = !{null}
-!13 = !{}
-!14 = !DILocation(line: 2, column: 3, scope: !9)
-!15 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 2, type: !16, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !13)
-!16 = !DISubroutineType(types: !17)
-!17 = !{!18, !18}
-!18 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
-!23 = !DILocation(line: 3, column: 3, scope: !15)
+
+; Function Attrs: noinline nounwind optnone ssp uwtable(sync)
+define i32 @_Z3barv() #0 !dbg !19 {
+  ret i32 2, !dbg !20
+}
+
+!llvm.module.flags = !{!0, !1, !2, !3, !4, !5, !6}
+!llvm.dbg.cu = !{!7}
+!llvm.ident = !{!9}
+
+!0 = !{i32 2, !"SDK Version", [2 x i32] [i32 14, i32 0]}
+!1 = !{i32 7, !"Dwarf Version", i32 4}
+!2 = !{i32 2, !"Debug Info Version", i32 3}
+!3 = !{i32 1, !"wchar_size", i32 4}
+!4 = !{i32 8, !"PIC Level", i32 2}
+!5 = !{i32 7, !"uwtable", i32 1}
+!6 = !{i32 7, !"frame-pointer", i32 1}
+!7 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !8, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None, sysroot: "/Users/somepath", sdk: "MacOSX.sdk")
+!8 = !DIFile(filename: "a.cpp", directory: "/Users/shubham/Development/testclang")
+!9 = !{!"clang"}
+!10 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !11, file: !11, line: 1, type: !12, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !7, retainedNodes: !15)
+!11 = !DIFile(filename: "./foo.h", directory: "/Users/shubham/Development/testclang")
+!12 = !DISubroutineType(types: !13)
+!13 = !{!14}
+!14 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!15 = !{}
+!16 = !DILocation(line: 2, column: 3, scope: !10)
+!17 = distinct !DISubprogram(name: "foo2", linkageName: "_Z4foo2v", scope: !11, file: !11, line: 4, type: !12, scopeLine: 4, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !7, retainedNodes: !15)
+!18 = !DILocation(line: 5, column: 3, scope: !17)
+!19 = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv", scope: !8, file: !8, line: 2, type: !12, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !7, retainedNodes: !15)
+!20 = !DILocation(line: 3, column: 3, scope: !19)
+
 
 //--- b.ll
 
-target triple = "arm64-apple-macosx12.0.0"
-define i32 @baz() #0 !dbg !9 {
-  ret i32 1, !dbg !14
+; ModuleID = 'b.cpp'
+source_filename = "b.cpp"
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "arm64-apple-macosx13.0.0"
+
+; Function Attrs: noinline nounwind optnone ssp uwtable(sync)
+define i32 @_Z3bazv() #0 !dbg !10 {
+  ret i32 1, !dbg !15
+}
+
+; Function Attrs: noinline nounwind optnone ssp uwtable(sync)
+define i32 @_Z3foov() #0 !dbg !16 {
+  ret i32 3, !dbg !18
 }
-define void @foo() #0 !dbg !15 {
-  ret void, !dbg !19
+
+; Function Attrs: noinline nounwind optnone ssp uwtable(sync)
+define i32 @_Z4foo2v() #0 !dbg !19 {
+  ret i32 4, !dbg !20
 }
-define void @bar(i32 noundef %x) #0 !dbg !20 {
-entry:
-ret void, !dbg !27
+
+; Function Attrs: noinline nounwind optnone ssp uwtable(sync)
+define i32 @_Z3barv() #0 !dbg !21 {
+  ret i32 2, !dbg !22
 }
-attributes #0 = { noinline nounwind optnone ssp uwtable "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="penryn" "target-features"="+cx16,+cx8,+fxsr,+mmx,+sahf,+sse,+sse2,+sse3,+sse4.1,+ssse3,+x87" "tune-cpu"="generic" }
-!llvm.dbg.cu = !{!0}
-!llvm.module.flags = !{!2, !3, !4, !5, !6, !7}
-!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 16.0.0 (https://github.com/apple/llvm-project.git d74d0d9fde90cccba7bf18066ac56e55e4402948)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None, sysroot: "/")
-!1 = !DIFile(filename: "b.c", directory: "/Users/shubham/Development/CASDelta")
-!2 = !{i32 7, !"Dwarf Version", i32 4}
-!3 = !{i32 2, !"Debug Info Version", i32 3}
-!4 = !{i32 1, !"wchar_size", i32 4}
-!5 = !{i32 7, !"PIC Level", i32 2}
-!6 = !{i32 7, !"uwtable", i32 2}
-!7 = !{i32 7, !"frame-pointer", i32 2}
-!9 = distinct !DISubprogram(name: "baz", scope: !1, file: !1, line: 1, type: !10, scopeLine: 1, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !13)
-!10 = !DISubroutineType(types: !11)
-!11 = !{!12}
-!12 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
-!13 = !{}
-!14 = !DILocation(line: 2, column: 5, scope: !9)
-!15 = distinct !DISubprogram(name: "foo", scope: !16, file: !16, line: 1, type: !17, scopeLine: 1, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !13)
-!16 = !DIFile(filename: "./foo.h", directory: "/Users/shubham/Development/CASDelta")
-!17 = !DISubroutineType(types: !18)
-!18 = !{null}
-!19 = !DILocation(line: 2, column: 3, scope: !15)
-!20 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 6, type: !21, scopeLine: 6, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !13)
-!21 = !DISubroutineType(types: !22)
-!22 = !{!12, !12}
-!25 = !DILocation(line: 7, column: 10, scope: !20)
-!26 = !DILocation(line: 7, column: 11, scope: !20)
-!27 = !DILocation(line: 7, column: 3, scope: !20)
+
+!llvm.module.flags = !{!0, !1, !2, !3, !4, !5, !6}
+!llvm.dbg.cu = !{!7}
+!llvm.ident = !{!9}
+
+!0 = !{i32 2, !"SDK Version", [2 x i32] [i32 14, i32 0]}
+!1 = !{i32 7, !"Dwarf Version", i32 4}
+!2 = !{i32 2, !"Debug Info Version", i32 3}
+!3 = !{i32 1, !"wchar_size", i32 4}
+!4 = !{i32 8, !"PIC Level", i32 2}
+!5 = !{i32 7, !"uwtable", i32 1}
+!6 = !{i32 7, !"frame-pointer", i32 1}
+!7 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !8, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None, sysroot: "/Users/somepath", sdk: "MacOSX.some.sdk")
+!8 = !DIFile(filename: "b.cpp", directory: "/Users/shubham/Development/testclang")
+!9 = !{!"clang"}
+!10 = distinct !DISubprogram(name: "baz", linkageName: "_Z3bazv", scope: !8, file: !8, line: 1, type: !11, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !7, retainedNodes: !14)
+!11 = !DISubroutineType(types: !12)
+!12 = !{!13}
+!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!14 = !{}
+!15 = !DILocation(line: 2, column: 5, scope: !10)
+!16 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !17, file: !17, line: 1, type: !11, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !7, retainedNodes: !14)
+!17 = !DIFile(filename: "./foo.h", directory: "/Users/shubham/Development/testclang")
+!18 = !DILocation(line: 2, column: 3, scope: !16)
+!19 = distinct !DISubprogram(name: "foo2", linkageName: "_Z4foo2v", scope: !17, file: !17, line: 4, type: !11, scopeLine: 4, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !7, retainedNodes: !14)
+!20 = !DILocation(line: 5, column: 3, scope: !19)
+!21 = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv", scope: !8, file: !8, line: 5, type: !11, scopeLine: 5, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !7, retainedNodes: !14)
+!22 = !DILocation(line: 6, column: 5, scope: !21)
diff --git a/llvm/test/DebugInfo/X86/cas-friendly.ll b/llvm/test/DebugInfo/X86/cas-friendly.ll
@@ -27,7 +27,6 @@
 ; CHECK-NEXT: 0x{{[0-9a-z]+}}     10      2      1   0             0 
 ; CHECK-NEXT: 0x{{[0-9a-z]+}}     10      2      1   0             0  epilogue_begin
 ; CHECK-NEXT: 0x{{[0-9a-z]+}}     10      2      1   0             0  end_sequence
-; CHECK-NEXT: 0x{{[0-9a-z]+}}      1      0      1   0             0  is_stmt end_sequence
 
 ; ModuleID = './test.c'
 source_filename = "./test.c"
diff --git a/llvm/test/tools/llvm-cas-dump/basic_debug_test.ll b/llvm/test/tools/llvm-cas-dump/basic_debug_test.ll
@@ -16,8 +16,7 @@
 ; DWARF:            version: 4
 ; DWARF:    prologue_length: 0x000000{{[0-9a-f]+}}
 ; DWARF: 0x0000000000000000      3      3      1   0             0  is_stmt prologue_end
-; DWARF: 0x0000000000000000      3      3      1   0             0  is_stmt end_sequence
-; DWARF: 0x0000000000000008      1      0      1   0             0  is_stmt end_sequence
+; DWARF: 0x0000000000000008      3      3      1   0             0  is_stmt end_sequence
 
 ; CHECK:      mc:assembler  llvmcas://{{.*}}
 ; CHECK-NEXT:   mc:header  llvmcas://{{.*}}
@@ -44,7 +43,6 @@
 ; CHECK-NEXT:     mc:debug_line_section  llvmcas://{{.*}}
 ; CHECK-NEXT:       mc:debug_line_distinct_data  llvmcas://{{.*}}
 ; CHECK-NEXT:       mc:debug_line  llvmcas://{{.*}}
-; CHECK-NEXT:       mc:debug_line  llvmcas://{{.*}}
 ; CHECK-NEXT:       mc:padding  llvmcas://{{.*}}
 ; CHECK-NEXT:   mc:data_in_code  llvmcas://{{.*}}
 ; CHECK-NEXT:   mc:symbol_table  llvmcas://{{.*}}
