https://github.com/thechenli updated https://github.com/llvm/llvm-project/pull/220774
>From 12a0bb2224c5c58c9f37520a693cfaff70a41dd9 Mon Sep 17 00:00:00 2001 From: Chen Li <[email protected]> Date: Wed, 2 Sep 2026 17:36:11 -0700 Subject: [PATCH] [lldb][AMDGPU] Support terminal DW_OP_LLVM_piece_end --- lldb/source/Expression/DWARFExpression.cpp | 19 +++++++++++++ .../Expression/DWARFExpressionTest.cpp | 28 +++++++++++++++++++ 2 files changed, 47 insertions(+) diff --git a/lldb/source/Expression/DWARFExpression.cpp b/lldb/source/Expression/DWARFExpression.cpp index 60577bac07167..038db3dfec587 100644 --- a/lldb/source/Expression/DWARFExpression.cpp +++ b/lldb/source/Expression/DWARFExpression.cpp @@ -2228,6 +2228,25 @@ llvm::Expected<Value> DWARFExpression::Evaluate( return llvm::createStringError("unimplemented opcode %s", DW_OP_value_to_name(opcode)); + case DW_OP_LLVM_user: + if (op->getSubCode() == DW_OP_LLVM_piece_end) { + if (op->getEndOffset() != expr_data.size()) + return llvm::createStringError( + "DW_OP_LLVM_piece_end is only supported at the end of an " + "expression"); + + // LLDB already constructs a single composite in `pieces`, so a + // terminal DW_OP_LLVM_piece_end adds no information and can be ignored. + // TODO: Support multiple composites as described by the heterogeneous + // debugging extensions: + // https://llvm.org/docs/AMDGPUDwarfExtensionsForHeterogeneousDebugging.html + // TODO: Support the standard DW_OP_piece_end opcode once LLVM + // implements the DWARF 6 locations-on-the-stack proposal: + // https://dwarfstd.org/issues/230524.1-orig.html + break; + } + [[fallthrough]]; + default: if (eval_ctx.dwarf_cu) { const uint64_t operands_offset = op_offset + 1; diff --git a/lldb/unittests/Expression/DWARFExpressionTest.cpp b/lldb/unittests/Expression/DWARFExpressionTest.cpp index 4b4b911800ae8..31e629967c6a2 100644 --- a/lldb/unittests/Expression/DWARFExpressionTest.cpp +++ b/lldb/unittests/Expression/DWARFExpressionTest.cpp @@ -1597,6 +1597,34 @@ TEST_F(DWARFExpressionMockProcessTest, DW_OP_regx) { ExpectScalar(0xBEEF, Value::ContextType::RegisterInfo)); } +TEST_F(DWARFExpressionMockProcessTest, DW_OP_LLVM_piece_end) { + TestContext ctx; + constexpr uint64_t reg_value = 0x8877665544332211; + ASSERT_TRUE( + CreateTestContext(&ctx, "i386-pc-linux", RegisterValue(reg_value))); + + ExecutionContext exe_ctx(ctx.process_sp); + MockDwarfDelegate delegate = MockDwarfDelegate::Dwarf5(); + + // Match the expression emitted for a value split across two AMDGPU + // registers. A terminal DW_OP_LLVM_piece_end completes the composite. + EXPECT_THAT_EXPECTED( + Evaluate({DW_OP_regx, 0x20, DW_OP_piece, 4, DW_OP_regx, 0x21, DW_OP_piece, + 4, DW_OP_LLVM_user, DW_OP_LLVM_piece_end}, + {}, &delegate, &exe_ctx, ctx.reg_ctx_sp.get()), + ExpectHostAddress({0x11, 0x22, 0x33, 0x44, 0x11, 0x22, 0x33, 0x44})); +} + +TEST(DWARFExpression, DW_OP_LLVM_piece_end_multiple) { + EXPECT_THAT_ERROR( + Evaluate({DW_OP_const1u, 0xaa, DW_OP_piece, 1, DW_OP_LLVM_user, + DW_OP_LLVM_piece_end, DW_OP_LLVM_user, DW_OP_LLVM_piece_end}) + .takeError(), + llvm::FailedWithMessage( + "DW_OP_LLVM_piece_end is only supported at the end of an " + "expression")); +} + TEST_F(DWARFExpressionMockProcessTest, DW_OP_deref_size_zero) { // DW_OP_deref_size with size 0 must report an error instead of constructing // a DataExtractor with addr_size 0 (caught by lldb-dwarf-expression-fuzzer: _______________________________________________ lldb-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
