https://github.com/MrEven132 updated https://github.com/llvm/llvm-project/pull/218335
>From 638722257b3ba98487cc33376c0b5e926fefff34 Mon Sep 17 00:00:00 2001 From: MrEven132 <[email protected]> Date: Tue, 25 Aug 2026 12:08:12 +0800 Subject: [PATCH 1/6] [lldb][NFC] Add a helper to identify potentially generic operands --- lldb/source/Expression/DWARFExpression.cpp | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/lldb/source/Expression/DWARFExpression.cpp b/lldb/source/Expression/DWARFExpression.cpp index 91c47546eeac7..d4504dafa3321 100644 --- a/lldb/source/Expression/DWARFExpression.cpp +++ b/lldb/source/Expression/DWARFExpression.cpp @@ -1380,6 +1380,15 @@ static llvm::Error CheckScalarOperandsHaveSameType(const Scalar &lhs, return llvm::Error::success(); } +// Scalar does not preserve DWARF's generic type identifier. Since generic +// values are address-sized integers, use the scalar kind and width as an +// approximation. +static bool IsPotentiallyGenericIntegerOperand(const Scalar &operand, + size_t address_size) { + return address_size != 0 && operand.GetType() == Scalar::e_int && + operand.GetByteSize() == address_size; +} + llvm::Expected<Value> DWARFExpression::Evaluate( ExecutionContext *exe_ctx, RegisterContext *reg_ctx, lldb::ModuleSP module_sp, const DataExtractor &opcodes, >From 829e50bfa0293db88a52b52489a8cefa8ea2404d Mon Sep 17 00:00:00 2001 From: MrEven132 <[email protected]> Date: Tue, 25 Aug 2026 12:09:02 +0800 Subject: [PATCH 2/6] [lldb] Compare generic DW_OP_ge operands as signed --- lldb/source/Expression/DWARFExpression.cpp | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/lldb/source/Expression/DWARFExpression.cpp b/lldb/source/Expression/DWARFExpression.cpp index d4504dafa3321..c101c8cf73058 100644 --- a/lldb/source/Expression/DWARFExpression.cpp +++ b/lldb/source/Expression/DWARFExpression.cpp @@ -1754,6 +1754,11 @@ llvm::Expected<Value> DWARFExpression::Evaluate( return err; tmp = stack.back(); stack.pop_back(); + if (IsPotentiallyGenericIntegerOperand(tmp.GetScalar(), address_size) && + IsPotentiallyGenericIntegerOperand(stack.back().GetScalar(), address_size)) { + tmp.GetScalar().MakeSigned(); + stack.back().GetScalar().MakeSigned(); + } stack.back().GetScalar() = to_generic(stack.back().GetScalar() >= tmp.GetScalar()); break; >From 122988dd18dd86d2925510d12de8da7fa2d2965e Mon Sep 17 00:00:00 2001 From: MrEven132 <[email protected]> Date: Tue, 25 Aug 2026 12:09:32 +0800 Subject: [PATCH 3/6] [lldb] Compare generic DW_OP_gt operands as signed --- lldb/source/Expression/DWARFExpression.cpp | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/lldb/source/Expression/DWARFExpression.cpp b/lldb/source/Expression/DWARFExpression.cpp index c101c8cf73058..5ef5d51982f91 100644 --- a/lldb/source/Expression/DWARFExpression.cpp +++ b/lldb/source/Expression/DWARFExpression.cpp @@ -1770,6 +1770,11 @@ llvm::Expected<Value> DWARFExpression::Evaluate( return err; tmp = stack.back(); stack.pop_back(); + if (IsPotentiallyGenericIntegerOperand(tmp.GetScalar(), address_size) && + IsPotentiallyGenericIntegerOperand(stack.back().GetScalar(), address_size)) { + tmp.GetScalar().MakeSigned(); + stack.back().GetScalar().MakeSigned(); + } stack.back().GetScalar() = to_generic(stack.back().GetScalar() > tmp.GetScalar()); break; >From fcf135114b490fda46f5f1cf14bdd1e83026acd0 Mon Sep 17 00:00:00 2001 From: MrEven132 <[email protected]> Date: Tue, 25 Aug 2026 12:10:11 +0800 Subject: [PATCH 4/6] [lldb] Compare generic DW_OP_le operands as signed --- lldb/source/Expression/DWARFExpression.cpp | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/lldb/source/Expression/DWARFExpression.cpp b/lldb/source/Expression/DWARFExpression.cpp index 5ef5d51982f91..fdbcb768dc8fb 100644 --- a/lldb/source/Expression/DWARFExpression.cpp +++ b/lldb/source/Expression/DWARFExpression.cpp @@ -1786,6 +1786,11 @@ llvm::Expected<Value> DWARFExpression::Evaluate( return err; tmp = stack.back(); stack.pop_back(); + if (IsPotentiallyGenericIntegerOperand(tmp.GetScalar(), address_size) && + IsPotentiallyGenericIntegerOperand(stack.back().GetScalar(), address_size)) { + tmp.GetScalar().MakeSigned(); + stack.back().GetScalar().MakeSigned(); + } stack.back().GetScalar() = to_generic(stack.back().GetScalar() <= tmp.GetScalar()); break; >From 48339a9ea6dd06650a22ea517a82242fb1991275 Mon Sep 17 00:00:00 2001 From: MrEven132 <[email protected]> Date: Tue, 25 Aug 2026 12:10:33 +0800 Subject: [PATCH 5/6] [lldb] Compare generic DW_OP_lt operands as signed --- lldb/source/Expression/DWARFExpression.cpp | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/lldb/source/Expression/DWARFExpression.cpp b/lldb/source/Expression/DWARFExpression.cpp index fdbcb768dc8fb..bdd77fa5af106 100644 --- a/lldb/source/Expression/DWARFExpression.cpp +++ b/lldb/source/Expression/DWARFExpression.cpp @@ -1802,6 +1802,11 @@ llvm::Expected<Value> DWARFExpression::Evaluate( return err; tmp = stack.back(); stack.pop_back(); + if (IsPotentiallyGenericIntegerOperand(tmp.GetScalar(), address_size) && + IsPotentiallyGenericIntegerOperand(stack.back().GetScalar(), address_size)) { + tmp.GetScalar().MakeSigned(); + stack.back().GetScalar().MakeSigned(); + } stack.back().GetScalar() = to_generic(stack.back().GetScalar() < tmp.GetScalar()); break; >From 4ff57cf6198d521b9a74e4f06edbc212318c65a3 Mon Sep 17 00:00:00 2001 From: MrEven132 <[email protected]> Date: Tue, 25 Aug 2026 12:41:56 +0800 Subject: [PATCH 6/6] [lldb] Test signed generic DWARF relational comparisons --- .../Expression/DWARFExpressionTest.cpp | 39 +++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/lldb/unittests/Expression/DWARFExpressionTest.cpp b/lldb/unittests/Expression/DWARFExpressionTest.cpp index 094cfaf790a9a..50bdc96be7c93 100644 --- a/lldb/unittests/Expression/DWARFExpressionTest.cpp +++ b/lldb/unittests/Expression/DWARFExpressionTest.cpp @@ -766,6 +766,45 @@ TEST(DWARFExpression, RelationalOpsProduceGenericResult) { } } +TEST(DWARFExpression, GenericRelationalOpsUseSignedComparison) { + struct TestCase { + uint8_t opcode; + uint8_t expected; + }; + constexpr TestCase test_cases[] = { + {DW_OP_lt, 1}, {DW_OP_le, 1}, {DW_OP_gt, 0}, {DW_OP_ge, 0}}; + + for (const TestCase &test : test_cases) { + // Generic relational operands are compared as signed values, so the + // unsigned encoding of all-one bits below represents -1 for comparison. + const std::vector<uint8_t> expr = { + DW_OP_const8u, + 0xff, + 0xff, + 0xff, + 0xff, + 0xff, + 0xff, + 0xff, + 0xff, + DW_OP_consts, + 0x00, + test.opcode, + DW_OP_stack_value, + }; + DataExtractor extractor(expr.data(), expr.size(), lldb::eByteOrderLittle, + /*addr_size=*/8); + + EXPECT_THAT_EXPECTED( + DWARFExpression::Evaluate( + /*exe_ctx=*/nullptr, /*reg_ctx=*/nullptr, /*module_sp=*/{}, + extractor, /*unit=*/nullptr, lldb::eRegisterKindLLDB, + /*initial_value_ptr=*/nullptr, /*object_address_ptr=*/nullptr), + ExpectScalar(64, test.expected, false)) + << "opcode 0x" << llvm::utohexstr(test.opcode); + } +} + TEST(DWARFExpression, DW_OP_stack_value) { EXPECT_THAT_EXPECTED(Evaluate({DW_OP_stack_value}), llvm::Failed()); } _______________________________________________ lldb-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
