From: Florian Hahn Date: Tue, 13 Jun 2017 16:54:44 +0000 (+0000) Subject: Align definition of DW_OP_plus with DWARF spec [1/3] X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=10ccfa6a1e7efc62fb55961986ada2c442a17491;p=llvm Align definition of DW_OP_plus with DWARF spec [1/3] Summary: This patch is part of 3 patches that together form a single patch, but must be introduced in stages in order not to break things. The way that LLVM interprets DW_OP_plus in DIExpression nodes is basically that of the DW_OP_plus_uconst operator since LLVM expects an unsigned constant operand. This unnecessarily restricts the DW_OP_plus operator, preventing it from being used to describe the evaluation of runtime values on the expression stack. These patches try to align the semantics of DW_OP_plus and DW_OP_minus with that of the DWARF definition, which pops two elements off the expression stack, performs the operation and pushes the result back on the stack. This is done in three stages: • The first patch (LLVM) adds support for DW_OP_plus_uconst. • The second patch (Clang) contains changes all its uses from DW_OP_plus to DW_OP_plus_uconst. • The third patch (LLVM) changes the semantics of DW_OP_plus and DW_OP_minus to be in line with its DWARF meaning. This patch includes the bitcode upgrade from legacy DIExpressions. Patch by Sander de Smalen. Reviewers: pcc, echristo, aprantl Reviewed By: aprantl Subscribers: fhahn, aprantl, javed.absar, llvm-commits Differential Revision: https://reviews.llvm.org/D33892 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305304 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/docs/LangRef.rst b/docs/LangRef.rst index 794f896806e..24362825d82 100644 --- a/docs/LangRef.rst +++ b/docs/LangRef.rst @@ -4405,6 +4405,7 @@ The current supported vocabulary is limited: - ``DW_OP_deref`` dereferences the top of the expression stack. - ``DW_OP_plus, 93`` adds ``93`` to the working expression. +- ``DW_OP_plus_uconst, 93`` adds ``93`` to the working expression. - ``DW_OP_LLVM_fragment, 16, 8`` specifies the offset and size (``16`` and ``8`` here, respectively) of the variable fragment from the working expression. Note that contrary to DW_OP_bit_piece, the offset is describing the the location @@ -4427,6 +4428,7 @@ combined with a concrete location. !0 = !DIExpression(DW_OP_deref) !1 = !DIExpression(DW_OP_plus, 3) + !1 = !DIExpression(DW_OP_plus_uconst, 3) !2 = !DIExpression(DW_OP_bit_piece, 3, 7) !3 = !DIExpression(DW_OP_deref, DW_OP_plus, 3, DW_OP_LLVM_fragment, 3, 7) !4 = !DIExpression(DW_OP_constu, 2, DW_OP_swap, DW_OP_xderef) diff --git a/lib/CodeGen/AsmPrinter/DwarfExpression.cpp b/lib/CodeGen/AsmPrinter/DwarfExpression.cpp index d96479f4343..73ce58e3ca5 100644 --- a/lib/CodeGen/AsmPrinter/DwarfExpression.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfExpression.cpp @@ -248,6 +248,12 @@ bool DwarfExpression::addMachineRegExpression(const TargetRegisterInfo &TRI, assert(Reg.Size == 0 && "subregister has same size as superregister"); // Pattern-match combinations for which more efficient representations exist. + // [Reg, DW_OP_plus_uconst, Offset] --> [DW_OP_breg, Offset]. + if (Op && (Op->getOp() == dwarf::DW_OP_plus_uconst)) { + SignedOffset = Op->getArg(0); + ExprCursor.take(); + } + // [Reg, Offset, DW_OP_plus] --> [DW_OP_breg, Offset]. // [Reg, Offset, DW_OP_minus] --> [DW_OP_breg, -Offset]. // If Reg is a subregister we need to mask it out before subtracting. @@ -321,6 +327,7 @@ void DwarfExpression::addExpression(DIExpressionCursor &&ExprCursor, return; } case dwarf::DW_OP_plus: + case dwarf::DW_OP_plus_uconst: assert(LocationKind != Register); emitOp(dwarf::DW_OP_plus_uconst); emitUnsigned(Op->getArg(0)); diff --git a/lib/IR/DebugInfoMetadata.cpp b/lib/IR/DebugInfoMetadata.cpp index e6c49cad072..a34f8d9eac1 100644 --- a/lib/IR/DebugInfoMetadata.cpp +++ b/lib/IR/DebugInfoMetadata.cpp @@ -599,6 +599,7 @@ unsigned DIExpression::ExprOperand::getSize() const { return 3; case dwarf::DW_OP_constu: case dwarf::DW_OP_plus: + case dwarf::DW_OP_plus_uconst: case dwarf::DW_OP_minus: return 2; default: @@ -641,6 +642,7 @@ bool DIExpression::isValid() const { break; } case dwarf::DW_OP_constu: + case dwarf::DW_OP_plus_uconst: case dwarf::DW_OP_plus: case dwarf::DW_OP_minus: case dwarf::DW_OP_deref: @@ -679,7 +681,8 @@ bool DIExpression::extractIfOffset(int64_t &Offset) const { } if (getNumElements() != 2) return false; - if (Elements[0] == dwarf::DW_OP_plus) { + if (Elements[0] == dwarf::DW_OP_plus || + Elements[0] == dwarf::DW_OP_plus_uconst) { Offset = Elements[1]; return true; } diff --git a/test/Assembler/diexpression.ll b/test/Assembler/diexpression.ll index c2fa3ee14c2..7d2d45b8bd0 100644 --- a/test/Assembler/diexpression.ll +++ b/test/Assembler/diexpression.ll @@ -1,8 +1,8 @@ ; RUN: llvm-as < %s | llvm-dis | llvm-as | llvm-dis | FileCheck %s ; RUN: verify-uselistorder %s -; CHECK: !named = !{!0, !1, !2, !3, !4, !5} -!named = !{!0, !1, !2, !3, !4, !5} +; CHECK: !named = !{!0, !1, !2, !3, !4, !5, !6} +!named = !{!0, !1, !2, !3, !4, !5, !6} ; CHECK: !0 = !DIExpression() ; CHECK-NEXT: !1 = !DIExpression(DW_OP_deref) @@ -10,9 +10,11 @@ ; CHECK-NEXT: !3 = !DIExpression(DW_OP_LLVM_fragment, 3, 7) ; CHECK-NEXT: !4 = !DIExpression(DW_OP_deref, DW_OP_plus, 3, DW_OP_LLVM_fragment, 3, 7) ; CHECK-NEXT: !5 = !DIExpression(DW_OP_constu, 2, DW_OP_swap, DW_OP_xderef) +; CHECK-NEXT: !6 = !DIExpression(DW_OP_plus_uconst, 3) !0 = !DIExpression() !1 = !DIExpression(DW_OP_deref) !2 = !DIExpression(DW_OP_plus, 3) !3 = !DIExpression(DW_OP_LLVM_fragment, 3, 7) !4 = !DIExpression(DW_OP_deref, DW_OP_plus, 3, DW_OP_LLVM_fragment, 3, 7) !5 = !DIExpression(DW_OP_constu, 2, DW_OP_swap, DW_OP_xderef) +!6 = !DIExpression(DW_OP_plus_uconst, 3) diff --git a/unittests/IR/MetadataTest.cpp b/unittests/IR/MetadataTest.cpp index bcf3babf7f6..a09a4239ec4 100644 --- a/unittests/IR/MetadataTest.cpp +++ b/unittests/IR/MetadataTest.cpp @@ -2043,6 +2043,7 @@ TEST_F(DIExpressionTest, isValid) { // Valid constructions. EXPECT_VALID(dwarf::DW_OP_plus, 6); + EXPECT_VALID(dwarf::DW_OP_plus_uconst, 6); EXPECT_VALID(dwarf::DW_OP_deref); EXPECT_VALID(dwarf::DW_OP_LLVM_fragment, 3, 7); EXPECT_VALID(dwarf::DW_OP_plus, 6, dwarf::DW_OP_deref); @@ -2054,6 +2055,7 @@ TEST_F(DIExpressionTest, isValid) { // Invalid constructions. EXPECT_INVALID(~0u); EXPECT_INVALID(dwarf::DW_OP_plus); + EXPECT_INVALID(dwarf::DW_OP_plus_uconst); EXPECT_INVALID(dwarf::DW_OP_LLVM_fragment); EXPECT_INVALID(dwarf::DW_OP_LLVM_fragment, 3); EXPECT_INVALID(dwarf::DW_OP_LLVM_fragment, 3, 7, dwarf::DW_OP_plus, 3);