[llvm] r295486 - Debug Info: Sort frame index expressions before emitting them.

Adrian Prantl via llvm-commits llvm-commits at lists.llvm.org
Fri Feb 17 11:42:32 PST 2017


Author: adrian
Date: Fri Feb 17 13:42:32 2017
New Revision: 295486

URL: http://llvm.org/viewvc/llvm-project?rev=295486&view=rev
Log:
Debug Info: Sort frame index expressions before emitting them.
This fixes PR31381, which caused an assertion and/or invalid debug info.

This affects debug variables that have multiple fragments in the MMI
side (i.e.: in the stack frame) table.
rdar://problem/30571676

Added:
    llvm/trunk/test/DebugInfo/X86/FrameIndexExprs.ll
Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp?rev=295486&r1=295485&r2=295486&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp Fri Feb 17 13:42:32 2017
@@ -522,22 +522,19 @@ DIE *DwarfCompileUnit::constructVariable
   }
 
   // .. else use frame index.
-  if (DV.getFrameIndex().empty())
+  if (!DV.hasFrameIndexExprs())
     return VariableDie;
 
-  auto Expr = DV.getExpression().begin();
   DIELoc *Loc = new (DIEValueAllocator) DIELoc;
   DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
-  for (auto FI : DV.getFrameIndex()) {
+  for (auto &Fragment : DV.getFrameIndexExprs()) {
     unsigned FrameReg = 0;
     const TargetFrameLowering *TFI = Asm->MF->getSubtarget().getFrameLowering();
-    int Offset = TFI->getFrameIndexReference(*Asm->MF, FI, FrameReg);
-    assert(Expr != DV.getExpression().end() && "Wrong number of expressions");
-    DwarfExpr.addFragmentOffset(*Expr);
+    int Offset = TFI->getFrameIndexReference(*Asm->MF, Fragment.FI, FrameReg);
+    DwarfExpr.addFragmentOffset(Fragment.Expr);
     DwarfExpr.AddMachineRegIndirect(*Asm->MF->getSubtarget().getRegisterInfo(),
                                     FrameReg, Offset);
-    DwarfExpr.AddExpression(*Expr);
-    ++Expr;
+    DwarfExpr.AddExpression(Fragment.Expr);
   }
   addBlock(*VariableDie, dwarf::DW_AT_location, DwarfExpr.finalize());
 

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=295486&r1=295485&r2=295486&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Fri Feb 17 13:42:32 2017
@@ -199,6 +199,15 @@ const DIType *DbgVariable::getType() con
   return Ty;
 }
 
+ArrayRef<DbgVariable::FrameIndexExpr> DbgVariable::getFrameIndexExprs() const {
+  std::sort(FrameIndexExprs.begin(), FrameIndexExprs.end(),
+            [](const FrameIndexExpr &A, const FrameIndexExpr &B) -> bool {
+              return A.Expr->getFragmentInfo()->OffsetInBits <
+                     B.Expr->getFragmentInfo()->OffsetInBits;
+            });
+  return FrameIndexExprs;
+}
+
 static const DwarfAccelTable::Atom TypeAtoms[] = {
     DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
     DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h?rev=295486&r1=295485&r2=295486&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h Fri Feb 17 13:42:32 2017
@@ -54,7 +54,7 @@ class MachineModuleInfo;
 ///
 /// Variables can be created from allocas, in which case they're generated from
 /// the MMI table.  Such variables can have multiple expressions and frame
-/// indices.  The \a Expr and \a FrameIndices array must match.
+/// indices.
 ///
 /// Variables can be created from \c DBG_VALUE instructions.  Those whose
 /// location changes over time use \a DebugLocListIndex, while those with a
@@ -64,11 +64,16 @@ class MachineModuleInfo;
 class DbgVariable {
   const DILocalVariable *Var;                /// Variable Descriptor.
   const DILocation *IA;                      /// Inlined at location.
-  SmallVector<const DIExpression *, 1> Expr; /// Complex address.
   DIE *TheDIE = nullptr;                     /// Variable DIE.
   unsigned DebugLocListIndex = ~0u;          /// Offset in DebugLocs.
   const MachineInstr *MInsn = nullptr;       /// DBG_VALUE instruction.
-  SmallVector<int, 1> FrameIndex;            /// Frame index.
+
+  struct FrameIndexExpr {
+    int FI;
+    const DIExpression *Expr;
+  };
+  mutable SmallVector<FrameIndexExpr, 1>
+      FrameIndexExprs; /// Frame index + expression.
 
 public:
   /// Construct a DbgVariable.
@@ -80,21 +85,18 @@ public:
 
   /// Initialize from the MMI table.
   void initializeMMI(const DIExpression *E, int FI) {
-    assert(Expr.empty() && "Already initialized?");
-    assert(FrameIndex.empty() && "Already initialized?");
+    assert(FrameIndexExprs.empty() && "Already initialized?");
     assert(!MInsn && "Already initialized?");
 
     assert((!E || E->isValid()) && "Expected valid expression");
     assert(~FI && "Expected valid index");
 
-    Expr.push_back(E);
-    FrameIndex.push_back(FI);
+    FrameIndexExprs.push_back({FI, E});
   }
 
   /// Initialize from a DBG_VALUE instruction.
   void initializeDbgValue(const MachineInstr *DbgValue) {
-    assert(Expr.empty() && "Already initialized?");
-    assert(FrameIndex.empty() && "Already initialized?");
+    assert(FrameIndexExprs.empty() && "Already initialized?");
     assert(!MInsn && "Already initialized?");
 
     assert(Var == DbgValue->getDebugVariable() && "Wrong variable");
@@ -103,16 +105,15 @@ public:
     MInsn = DbgValue;
     if (auto *E = DbgValue->getDebugExpression())
       if (E->getNumElements())
-        Expr.push_back(E);
+        FrameIndexExprs.push_back({0, E});
   }
 
   // Accessors.
   const DILocalVariable *getVariable() const { return Var; }
   const DILocation *getInlinedAt() const { return IA; }
-  ArrayRef<const DIExpression *> getExpression() const { return Expr; }
   const DIExpression *getSingleExpression() const {
-    assert(MInsn && Expr.size() <= 1);
-    return Expr.size() ? Expr[0] : nullptr;
+    assert(MInsn && FrameIndexExprs.size() <= 1);
+    return FrameIndexExprs.size() ? FrameIndexExprs[0].Expr : nullptr;
   }
   void setDIE(DIE &D) { TheDIE = &D; }
   DIE *getDIE() const { return TheDIE; }
@@ -120,7 +121,9 @@ public:
   unsigned getDebugLocListIndex() const { return DebugLocListIndex; }
   StringRef getName() const { return Var->getName(); }
   const MachineInstr *getMInsn() const { return MInsn; }
-  ArrayRef<int> getFrameIndex() const { return FrameIndex; }
+  /// Get the FI entries, sorted by fragment offset.
+  ArrayRef<FrameIndexExpr> getFrameIndexExprs() const;
+  bool hasFrameIndexExprs() const { return !FrameIndexExprs.empty(); }
 
   void addMMIEntry(const DbgVariable &V) {
     assert(DebugLocListIndex == ~0U && !MInsn && "not an MMI entry");
@@ -128,16 +131,15 @@ public:
     assert(V.Var == Var && "conflicting variable");
     assert(V.IA == IA && "conflicting inlined-at location");
 
-    assert(!FrameIndex.empty() && "Expected an MMI entry");
-    assert(!V.FrameIndex.empty() && "Expected an MMI entry");
-    assert(Expr.size() == FrameIndex.size() && "Mismatched expressions");
-    assert(V.Expr.size() == V.FrameIndex.size() && "Mismatched expressions");
-
-    Expr.append(V.Expr.begin(), V.Expr.end());
-    FrameIndex.append(V.FrameIndex.begin(), V.FrameIndex.end());
-    assert(all_of(Expr, [](const DIExpression *E) {
-             return E && E->isFragment();
-           }) && "conflicting locations for variable");
+    assert(!FrameIndexExprs.empty() && "Expected an MMI entry");
+    assert(!V.FrameIndexExprs.empty() && "Expected an MMI entry");
+
+    FrameIndexExprs.append(V.FrameIndexExprs.begin(), V.FrameIndexExprs.end());
+    assert(all_of(FrameIndexExprs,
+                  [](FrameIndexExpr &FIE) {
+                    return FIE.Expr && FIE.Expr->isFragment();
+                  }) &&
+           "conflicting locations for variable");
   }
 
   // Translate tag to proper Dwarf tag.
@@ -167,11 +169,11 @@ public:
 
   bool hasComplexAddress() const {
     assert(MInsn && "Expected DBG_VALUE, not MMI variable");
-    assert(FrameIndex.empty() && "Expected DBG_VALUE, not MMI variable");
-    assert(
-        (Expr.empty() || (Expr.size() == 1 && Expr.back()->getNumElements())) &&
-        "Invalid Expr for DBG_VALUE");
-    return !Expr.empty();
+    assert((FrameIndexExprs.empty() ||
+            (FrameIndexExprs.size() == 1 &&
+             FrameIndexExprs[0].Expr->getNumElements())) &&
+           "Invalid Expr for DBG_VALUE");
+    return !FrameIndexExprs.empty();
   }
   bool isBlockByrefVariable() const;
   const DIType *getType() const;

Added: llvm/trunk/test/DebugInfo/X86/FrameIndexExprs.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/FrameIndexExprs.ll?rev=295486&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/FrameIndexExprs.ll (added)
+++ llvm/trunk/test/DebugInfo/X86/FrameIndexExprs.ll Fri Feb 17 13:42:32 2017
@@ -0,0 +1,85 @@
+; PR31381: An assertion in the DWARF backend when fragments in MMI slots are
+; sorted by largest offset first.
+; RUN: %llc_dwarf -filetype=obj < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s
+; CHECK: DW_TAG_formal_parameter
+; CHECK: DW_TAG_formal_parameter
+; CHECK-NEXT: DW_AT_location [DW_FORM_exprloc]  (<0xa> 91 78 93 03 93 06 91 7d 93 03 )
+;           fbreg -8, piece 0x00000003, piece 0x00000006, fbreg -3, piece 0x00000003 
+; CHECK-NEXT: DW_AT_abstract_origin {{.*}}"p"
+source_filename = "bugpoint-reduced-simplified.ll"
+target triple = "x86_64-apple-darwin"
+
+ at f = common local_unnamed_addr global i32 0, align 4, !dbg !0
+ at h = common local_unnamed_addr global i32 0, align 4, !dbg !6
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #0
+
+define void @fn4() local_unnamed_addr !dbg !12 {
+entry:
+  %l1.sroa.7.i = alloca [3 x i8], align 1
+  tail call void @llvm.dbg.declare(metadata [3 x i8]* %l1.sroa.7.i, metadata !15, metadata !26), !dbg !27
+  %i.sroa.4.i = alloca [3 x i8], align 8
+  tail call void @llvm.dbg.declare(metadata [3 x i8]* %i.sroa.4.i, metadata !15, metadata !32), !dbg !27
+  %0 = load i32, i32* @h, align 4
+  br label %while.body.i.i, !dbg !33
+
+while.body.i.i:                                   ; preds = %while.body.i.i, %entry
+  br label %while.body.i.i, !dbg !34
+
+fn3.exit:                                         ; No predecessors!
+  %1 = load i32, i32* @f, align 4
+  %tobool.i = icmp eq i32 %1, 0
+  br label %while.body.i
+
+while.body.i:                                     ; preds = %if.end.i, %fn3.exit
+  br i1 %tobool.i, label %if.end.i, label %if.then.i
+
+if.then.i:                                        ; preds = %while.body.i
+  br label %if.end.i
+
+if.end.i:                                         ; preds = %if.then.i, %while.body.i
+  br label %while.body.i
+}
+
+attributes #0 = { nounwind readnone }
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!9, !10, !11}
+
+!0 = !DIGlobalVariableExpression(var: !1)
+!1 = distinct !DIGlobalVariable(name: "f", scope: !2, file: !3, line: 8, type: !8, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
+!3 = !DIFile(filename: "PR31381.c", directory: "/")
+!4 = !{}
+!5 = !{!0, !6}
+!6 = !DIGlobalVariableExpression(var: !7)
+!7 = distinct !DIGlobalVariable(name: "h", scope: !2, file: !3, line: 8, type: !8, isLocal: false, isDefinition: true)
+!8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!9 = !{i32 2, !"Dwarf Version", i32 4}
+!10 = !{i32 2, !"Debug Info Version", i32 3}
+!11 = !{i32 1, !"PIC Level", i32 2}
+!12 = distinct !DISubprogram(name: "fn4", scope: !3, file: !3, line: 31, type: !13, isLocal: false, isDefinition: true, scopeLine: 32, isOptimized: true, unit: !2, variables: !4)
+!13 = !DISubroutineType(types: !14)
+!14 = !{null}
+!15 = !DILocalVariable(name: "p", arg: 1, scope: !16, file: !3, line: 19, type: !19)
+!16 = distinct !DISubprogram(name: "fn2", scope: !3, file: !3, line: 19, type: !17, isLocal: false, isDefinition: true, scopeLine: 20, flags: DIFlagPrototyped, isOptimized: true, unit: !2, variables: !25)
+!17 = !DISubroutineType(types: !18)
+!18 = !{null, !19}
+!19 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "S", file: !3, line: 1, size: 96, elements: !20)
+!20 = !{!21, !23, !24}
+!21 = !DIDerivedType(tag: DW_TAG_member, name: "b", scope: !19, file: !3, line: 4, baseType: !22, size: 8, offset: 24)
+!22 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
+!23 = !DIDerivedType(tag: DW_TAG_member, name: "c", scope: !19, file: !3, line: 5, baseType: !8, size: 32, offset: 32)
+!24 = !DIDerivedType(tag: DW_TAG_member, name: "d", scope: !19, file: !3, line: 6, baseType: !8, size: 6, offset: 64, flags: DIFlagBitField, extraData: i64 64)
+!25 = !{!15}
+!26 = !DIExpression(DW_OP_LLVM_fragment, 72, 24)
+!27 = !DILocation(line: 19, column: 20, scope: !16, inlinedAt: !28)
+!28 = distinct !DILocation(line: 27, column: 3, scope: !29, inlinedAt: !30)
+!29 = distinct !DISubprogram(name: "fn3", scope: !3, file: !3, line: 24, type: !13, isLocal: false, isDefinition: true, scopeLine: 25, isOptimized: true, unit: !2, variables: !4)
+!30 = distinct !DILocation(line: 34, column: 7, scope: !31)
+!31 = distinct !DILexicalBlock(scope: !12, file: !3, line: 33, column: 5)
+!32 = !DIExpression(DW_OP_LLVM_fragment, 0, 24)
+!33 = !DILocation(line: 22, column: 9, scope: !16, inlinedAt: !28)
+!34 = !DILocation(line: 21, column: 3, scope: !35, inlinedAt: !28)
+!35 = !DILexicalBlockFile(scope: !16, file: !3, discriminator: 2)




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