[llvm] r226627 - Make DIExpression::Verify() stricter by checking that the number of
Duncan P. N. Exon Smith
dexonsmith at apple.com
Tue Jan 20 18:05:02 PST 2015
> On 2015 Jan 20, at 16:59, Adrian Prantl <aprantl at apple.com> wrote:
>
> Author: adrian
> Date: Tue Jan 20 18:59:20 2015
> New Revision: 226627
>
> URL: http://llvm.org/viewvc/llvm-project?rev=226627&view=rev
> Log:
> Make DIExpression::Verify() stricter by checking that the number of
> elements and the ordering is sane and cleanup the accessors.
>
Funny, I was just wondering earlier today what sort of expressions are
valid.
> Added:
> llvm/trunk/test/DebugInfo/piece-verifier.ll
> Modified:
> llvm/trunk/include/llvm/IR/DebugInfo.h
> llvm/trunk/lib/IR/DebugInfo.cpp
> llvm/trunk/lib/IR/Verifier.cpp
>
> Modified: llvm/trunk/include/llvm/IR/DebugInfo.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/DebugInfo.h?rev=226627&r1=226626&r2=226627&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/IR/DebugInfo.h (original)
> +++ llvm/trunk/include/llvm/IR/DebugInfo.h Tue Jan 20 18:59:20 2015
> @@ -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();
>
>
> Modified: llvm/trunk/lib/IR/DebugInfo.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/DebugInfo.cpp?rev=226627&r1=226626&r2=226627&view=diff
> ==============================================================================
> --- llvm/trunk/lib/IR/DebugInfo.cpp (original)
> +++ llvm/trunk/lib/IR/DebugInfo.cpp Tue Jan 20 18:59:20 2015
> @@ -148,17 +148,18 @@ uint64_t DIExpression::getElement(unsign
> }
>
> 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());
> - return getElement(1);
> + assert(isVariablePiece() && "not a piece");
> + return getElement(getNumElements()-2);
> }
>
> uint64_t DIExpression::getPieceSize() const {
> - assert(isVariablePiece());
> - return getElement(2);
> + assert(isVariablePiece() && "not a piece");
> + 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())
The first part of the condition looks always true. Did you mean something
else (or am I confused?)?
Also, I'm not sure how/whether you've actually checked that this is the
last element.
> + return false;
> + I += 2;
> + break;
> + case DW_OP_plus:
> + // Takes one argument.
> + if (I+1 == N)
(Nit: I think we prefer `I + 1`.)
> + return false;
> + I += 1;
You might just simplify this all to:
if (++I == N)
return false;
> + break;
> + default: break;
Does this mean "don't know how to verify", or should this just be
rejected?
In the former case, I wonder if you should break the `for` loop entirely,
since there could be some argument to an unrecognized operator that
happens to be equal to a recognized `DW_OP_`. In the latter case,
shouldn't you just return `false`?
> + }
I feel like all of this new code should go *after* the more basic
verification.
> return isExpression() && DbgNode->getNumOperands() == 1;
I.e., here.
> }
>
>
> Modified: llvm/trunk/lib/IR/Verifier.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Verifier.cpp?rev=226627&r1=226626&r2=226627&view=diff
> ==============================================================================
> --- llvm/trunk/lib/IR/Verifier.cpp (original)
> +++ llvm/trunk/lib/IR/Verifier.cpp Tue Jan 20 18:59:20 2015
> @@ -2841,12 +2841,20 @@ void DebugInfoVerifier::processCallInst(
> if (Function *F = CI.getCalledFunction())
> if (Intrinsic::ID ID = (Intrinsic::ID)F->getIntrinsicID())
> switch (ID) {
> - case Intrinsic::dbg_declare:
> - Finder.processDeclare(*M, cast<DbgDeclareInst>(&CI));
> + case Intrinsic::dbg_declare: {
> + 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;
> }
>
> Added: llvm/trunk/test/DebugInfo/piece-verifier.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/piece-verifier.ll?rev=226627&view=auto
> ==============================================================================
> --- llvm/trunk/test/DebugInfo/piece-verifier.ll (added)
> +++ llvm/trunk/test/DebugInfo/piece-verifier.ll Tue Jan 20 18:59:20 2015
> @@ -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]
>
>
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