Make DIExpression::Verify() stricter by checking that the number of

elements and the ordering is sane and cleanup the accessors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226627 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/IR/DebugInfo.h

@@ -1036,6 +1036,9 @@ public:
   /// \brief Process DILocation.
   void processLocation(const Module &M, DILocation Loc);
 
+  /// \brief Process DIExpression.
+  void processExpression(DIExpression Expr);
+
   /// \brief Clear all lists.
   void reset();
 

lib/IR/DebugInfo.cpp

@@ -148,17 +148,18 @@ uint64_t DIExpression::getElement(unsigned Idx) const {
 }
 
 bool DIExpression::isVariablePiece() const {
-  return getNumElements() && getElement(0) == dwarf::DW_OP_piece;
+  unsigned N = getNumElements();
+  return N >=3 && getElement(N-3) == dwarf::DW_OP_piece;
 }
 
 uint64_t DIExpression::getPieceOffset() const {
-  assert(isVariablePiece());
+  assert(isVariablePiece() && "not a piece");
-  return getElement(1);
+  return getElement(getNumElements()-2);
 }
 
 uint64_t DIExpression::getPieceSize() const {
-  assert(isVariablePiece());
+  assert(isVariablePiece() && "not a piece");
-  return getElement(2);
+  return getElement(getNumElements()-1);
 }
 
 //===----------------------------------------------------------------------===//
@@ -593,6 +594,24 @@ bool DIExpression::Verify() const {
   if (!DbgNode)
     return true;
 
+  unsigned N = getNumElements();
+  for (unsigned I = 0; I < N; ++I)
+    switch (getElement(I)) {
+    case DW_OP_piece:
+      // DW_OP_piece has to be the last element in the expression and take two
+      // arguments.
+      if (getElement(I) == DW_OP_piece && !isVariablePiece())
+        return false;
+      I += 2;
+      break;
+    case DW_OP_plus:
+      // Takes one argument.
+      if (I+1 == N)
+        return false;
+      I += 1;
+      break;
+    default: break;
+  }
   return isExpression() && DbgNode->getNumOperands() == 1;
 }
 

lib/IR/Verifier.cpp

@@ -2841,12 +2841,20 @@ void DebugInfoVerifier::processCallInst(DebugInfoFinder &Finder,
   if (Function *F = CI.getCalledFunction())
     if (Intrinsic::ID ID = (Intrinsic::ID)F->getIntrinsicID())
       switch (ID) {
-      case Intrinsic::dbg_declare:
+      case Intrinsic::dbg_declare: {
-        Finder.processDeclare(*M, cast<DbgDeclareInst>(&CI));
+        auto *DDI = cast<DbgDeclareInst>(&CI);
+        Finder.processDeclare(*M, DDI);
+        if (auto E = DDI->getExpression())
+          Assert1(DIExpression(E).Verify(), "DIExpression does not Verify!", E);
         break;
-      case Intrinsic::dbg_value:
+      }
-        Finder.processValue(*M, cast<DbgValueInst>(&CI));
+      case Intrinsic::dbg_value: {
+        auto *DVI = cast<DbgValueInst>(&CI);
+        Finder.processValue(*M, DVI);
+        if (auto E = DVI->getExpression())
+          Assert1(DIExpression(E).Verify(), "DIExpression does not Verify!", E);
         break;
+      }
       default:
         break;
       }

test/DebugInfo/piece-verifier.ll

@@ -0,0 +1,54 @@
+; RUN: not llvm-as -disable-output -verify-debug-info < %s 2>&1 | FileCheck %s
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.9.0"
+
+; Function Attrs: nounwind ssp uwtable
+define i32 @foo(i64 %s.coerce0, i32 %s.coerce1) #0 {
+entry:
+  call void @llvm.dbg.value(metadata i64 %s.coerce0, i64 0, metadata !20, metadata !24), !dbg !21
+  call void @llvm.dbg.value(metadata i32 %s.coerce1, i64 0, metadata !22, metadata !27), !dbg !21
+  ret i32 %s.coerce1, !dbg !23
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #1
+
+attributes #0 = { nounwind ssp uwtable "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" }
+attributes #1 = { nounwind readnone }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!17, !18}
+!llvm.ident = !{!19}
+
+!0 = !{!"0x11\0012\00clang version 3.5 \001\00\000\00\001", !1, !2, !2, !3, !2, !2} ; [ DW_TAG_compile_unit ]
+!1 = !{!"pieces.c", !""}
+!2 = !{}
+!3 = !{!4}
+!4 = !{!"0x2e\00foo\00foo\00\003\000\001\000\006\00256\001\003", !1, !5, !6, null, i32 (i64, i32)* @foo, null, null, !15} ; [ DW_TAG_subprogram ] [line 3] [def] [foo]
+!5 = !{!"0x29", !1}          ; [ DW_TAG_file_type ] [/pieces.c]
+!6 = !{!"0x15\00\000\000\000\000\000\000", i32 0, null, null, !7, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!7 = !{!8, !9}
+!8 = !{!"0x24\00int\000\0032\0032\000\000\005", null, null} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
+!9 = !{!"0x16\00S\001\000\000\000\000", !1, null, !10} ; [ DW_TAG_typedef ] [S] [line 1, size 0, align 0, offset 0] [from ]
+!10 = !{!"0x13\00\001\00128\0064\000\000\000", !1, null, null, !11, null, null, null} ; [ DW_TAG_structure_type ] [line 1, size 128, align 64, offset 0] [def] [from ]
+!11 = !{!12, !14}
+!12 = !{!"0xd\00a\001\0064\0064\000\000", !1, !10, !13} ; [ DW_TAG_member ] [a] [line 1, size 64, align 64, offset 0] [from long int]
+!13 = !{!"0x24\00long int\000\0064\0064\000\000\005", null, null} ; [ DW_TAG_base_type ] [long int] [line 0, size 64, align 64, offset 0, enc DW_ATE_signed]
+!14 = !{!"0xd\00b\001\0032\0032\0064\000", !1, !10, !8} ; [ DW_TAG_member ] [b] [line 1, size 32, align 32, offset 64] [from int]
+!15 = !{!16}
+!16 = !{!"0x101\00s\0016777219\000", !4, !5, !9} ; [ DW_TAG_arg_variable ] [s] [line 3]
+!17 = !{i32 2, !"Dwarf Version", i32 4}
+!18 = !{i32 1, !"Debug Info Version", i32 2}
+!19 = !{!"clang version 3.5 "}
+!20 = !{!"0x101\00s\0016777219\000", !4, !5, !9} ; [ DW_TAG_arg_variable ] [s] [line 3]
+!21 = !MDLocation(line: 3, scope: !4)
+!22 = !{!"0x101\00s\0016777219\000", !4, !5, !9} ; [ DW_TAG_arg_variable ] [s] [line 3]
+!23 = !MDLocation(line: 4, scope: !4)
+!24 = !{!"0x102\006\00147\000\008"} ; [ DW_TAG_expression ] [DW_OP_piece 0 8] [piece, size 8, offset 0]
+!25 = !{}
+; This expression has elements after DW_OP_piece.
+; CHECK: DIExpression does not Verify
+!27 = !{!"0x102\00147\008\004\006"} ; [ DW_TAG_expression ] [DW_OP_piece 8 4] [piece, size 4, offset 8]