[llvm] r309034 - Debug Info: Support fragmented variables in the MMI side table

[Adrian Prantl via llvm-commits]

Author: adrian
Date: Tue Jul 25 14:29:22 2017
New Revision: 309034

URL: http://llvm.org/viewvc/llvm-project?rev=309034&view=rev
Log:
Debug Info: Support fragmented variables in the MMI side table

<rdar://problem/17816343>

Added:
    llvm/trunk/test/DebugInfo/X86/fi-piece.ll
Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=309034&r1=309033&r2=309034&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Tue Jul 25 14:29:22 2017
@@ -779,6 +779,7 @@ void DwarfDebug::ensureAbstractVariableI
 // Collect variable information from side table maintained by MF.
 void DwarfDebug::collectVariableInfoFromMFTable(
     DwarfCompileUnit &TheCU, DenseSet<InlinedVariable> &Processed) {
+  SmallDenseMap<const DILocalVariable *, DbgVariable *> MFVars;
   for (const auto &VI : Asm->MF->getVariableDbgInfo()) {
     if (!VI.Var)
       continue;
@@ -796,8 +797,12 @@ void DwarfDebug::collectVariableInfoFrom
     ensureAbstractVariableIsCreatedIfScoped(TheCU, Var, Scope->getScopeNode());
     auto RegVar = make_unique<DbgVariable>(Var.first, Var.second);
     RegVar->initializeMMI(VI.Expr, VI.Slot);
-    if (InfoHolder.addScopeVariable(Scope, RegVar.get()))
+    if (DbgVariable *DbgVar = MFVars.lookup(VI.Var))
+      DbgVar->addMMIEntry(*RegVar);
+    else if (InfoHolder.addScopeVariable(Scope, RegVar.get())) {
+      MFVars.insert({VI.Var, RegVar.get()});
       ConcreteVariables.push_back(std::move(RegVar));
+    }
   }
 }
 

Added: llvm/trunk/test/DebugInfo/X86/fi-piece.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/fi-piece.ll?rev=309034&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/fi-piece.ll (added)
+++ llvm/trunk/test/DebugInfo/X86/fi-piece.ll Tue Jul 25 14:29:22 2017
@@ -0,0 +1,51 @@
+; RUN: llc %s -filetype=obj -o - | llvm-dwarfdump - | FileCheck %s
+; Test that multi-DW_OP_piece expressions are emitted for FI variables.
+;
+; CHECK: .debug_info contents:
+; CHECK: DW_TAG_variable
+; CHECK:   DW_AT_location [DW_FORM_exprloc]	(<0x8> 91 7c 93 02 91 78 93 02 )
+;                       fbreg -8, piece 0x00000002, fbreg -4, piece 0x00000002
+; CHECK:   DW_AT_name {{.*}}"a"
+
+
+; ModuleID = '/tmp/t.c'
+source_filename = "/tmp/t.c"
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.12.0"
+
+; Function Attrs: noinline nounwind optnone ssp uwtable
+define void @f() #0 !dbg !8 {
+entry:
+  %a = alloca i16, align 4
+  %b = alloca i16, align 4
+  call void @llvm.dbg.declare(metadata i16* %a, metadata !11, metadata !DIExpression(DW_OP_LLVM_fragment, 0, 16)), !dbg !14
+  store i16 1, i16* %a, align 4, !dbg !14
+  call void @llvm.dbg.declare(metadata i16* %b, metadata !11, metadata !DIExpression(DW_OP_LLVM_fragment, 16, 16)), !dbg !16
+  store i16 2, i16* %b, align 4, !dbg !16
+  ret void
+}
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+attributes #0 = { noinline nounwind optnone ssp uwtable }
+attributes #1 = { nounwind readnone speculatable }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "adrian", emissionKind: FullDebug)
+!1 = !DIFile(filename: "/tmp/t.c", directory: "/")
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{i32 7, !"PIC Level", i32 2}
+!8 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 1, type: !9, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: false, unit: !0)
+!9 = !DISubroutineType(types: !10)
+!10 = !{null}
+!11 = !DILocalVariable(name: "a", scope: !8, file: !1, line: 2, type: !12)
+!12 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!13 = !DIExpression()
+!14 = !DILocation(line: 2, column: 7, scope: !8)
+!15 = !DILocalVariable(name: "b", scope: !8, file: !1, line: 3, type: !12)
+!16 = !DILocation(line: 3, column: 7, scope: !8)