4edb7e34f8
Dwarf says (Section 2.5.1.1. of DWARF v5) that these operations should push "generic" (pointer-sized) values. This was not the case for DW_OP_const operations (which were pushing values based on the size of arguments), nor DW_OP_litN (which were always pushing 64-bit values). The practical effect of this that were were unable to display the values of variables if the size of the DW_OP_const opcode was smaller than the value of the variable it was describing. This would happen because we would store this (small) result into a buffer and then would not be able to read sufficient data out of it (in Value::GetValueAsData). Gcc emits debug info like this. Other (more subtle) effects are also possible. The same fix should be applied to DW_OP_const[us] (leb128 versions), but I'm not doing that right now, because that would cause us to display wrong (truncated) values of variables on 32-bit targets (pr48087). Differential Revision: https://reviews.llvm.org/D90840
279 lines
9.8 KiB
C++
279 lines
9.8 KiB
C++
//===-- DWARFExpressionTest.cpp -------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "lldb/Expression/DWARFExpression.h"
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#include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
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#include "TestingSupport/Symbol/YAMLModuleTester.h"
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#include "lldb/Core/Value.h"
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#include "lldb/Core/dwarf.h"
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#include "lldb/Symbol/ObjectFile.h"
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#include "lldb/Utility/StreamString.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/Testing/Support/Error.h"
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#include "gtest/gtest.h"
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using namespace lldb_private;
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static llvm::Expected<Scalar> Evaluate(llvm::ArrayRef<uint8_t> expr,
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lldb::ModuleSP module_sp = {},
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DWARFUnit *unit = nullptr) {
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DataExtractor extractor(expr.data(), expr.size(), lldb::eByteOrderLittle,
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/*addr_size*/ 4);
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Value result;
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Status status;
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if (!DWARFExpression::Evaluate(
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/*exe_ctx*/ nullptr, /*reg_ctx*/ nullptr, module_sp, extractor, unit,
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lldb::eRegisterKindLLDB,
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/*initial_value_ptr*/ nullptr,
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/*object_address_ptr*/ nullptr, result, &status))
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return status.ToError();
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switch (result.GetValueType()) {
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case Value::eValueTypeScalar:
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return result.GetScalar();
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case Value::eValueTypeHostAddress: {
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// Convert small buffers to scalars to simplify the tests.
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DataBufferHeap &buf = result.GetBuffer();
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if (buf.GetByteSize() <= 8) {
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uint64_t val = 0;
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memcpy(&val, buf.GetBytes(), buf.GetByteSize());
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return Scalar(llvm::APInt(buf.GetByteSize()*8, val, false));
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}
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}
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LLVM_FALLTHROUGH;
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default:
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return status.ToError();
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}
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}
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class DWARFExpressionTester : public YAMLModuleTester {
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public:
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using YAMLModuleTester::YAMLModuleTester;
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llvm::Expected<Scalar> Eval(llvm::ArrayRef<uint8_t> expr) {
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return ::Evaluate(expr, m_module_sp, m_dwarf_unit);
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}
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};
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/// Unfortunately Scalar's operator==() is really picky.
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static Scalar GetScalar(unsigned bits, uint64_t value, bool sign) {
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Scalar scalar(value);
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scalar.TruncOrExtendTo(bits, sign);
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return scalar;
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}
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TEST(DWARFExpression, DW_OP_pick) {
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EXPECT_THAT_EXPECTED(Evaluate({DW_OP_lit1, DW_OP_lit0, DW_OP_pick, 0}),
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llvm::HasValue(0));
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EXPECT_THAT_EXPECTED(Evaluate({DW_OP_lit1, DW_OP_lit0, DW_OP_pick, 1}),
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llvm::HasValue(1));
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EXPECT_THAT_EXPECTED(Evaluate({DW_OP_lit1, DW_OP_lit0, DW_OP_pick, 2}),
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llvm::Failed());
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}
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TEST(DWARFExpression, DW_OP_const) {
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// Extend to address size.
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EXPECT_THAT_EXPECTED(Evaluate({DW_OP_const1u, 0x88}), llvm::HasValue(0x88));
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EXPECT_THAT_EXPECTED(Evaluate({DW_OP_const1s, 0x88}),
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llvm::HasValue(0xffffff88));
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EXPECT_THAT_EXPECTED(Evaluate({DW_OP_const2u, 0x47, 0x88}),
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llvm::HasValue(0x8847));
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EXPECT_THAT_EXPECTED(Evaluate({DW_OP_const2s, 0x47, 0x88}),
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llvm::HasValue(0xffff8847));
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EXPECT_THAT_EXPECTED(Evaluate({DW_OP_const4u, 0x44, 0x42, 0x47, 0x88}),
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llvm::HasValue(0x88474244));
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EXPECT_THAT_EXPECTED(Evaluate({DW_OP_const4s, 0x44, 0x42, 0x47, 0x88}),
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llvm::HasValue(0x88474244));
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// Truncate to address size.
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EXPECT_THAT_EXPECTED(
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Evaluate({DW_OP_const8u, 0x00, 0x11, 0x22, 0x33, 0x44, 0x42, 0x47, 0x88}),
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llvm::HasValue(0x33221100));
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EXPECT_THAT_EXPECTED(
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Evaluate({DW_OP_const8s, 0x00, 0x11, 0x22, 0x33, 0x44, 0x42, 0x47, 0x88}),
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llvm::HasValue(0x33221100));
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// Don't truncate to address size for compatibility with clang (pr48087).
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EXPECT_THAT_EXPECTED(
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Evaluate({DW_OP_constu, 0x81, 0x82, 0x84, 0x88, 0x90, 0xa0, 0x40}),
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llvm::HasValue(0x01010101010101));
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EXPECT_THAT_EXPECTED(
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Evaluate({DW_OP_consts, 0x81, 0x82, 0x84, 0x88, 0x90, 0xa0, 0x40}),
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llvm::HasValue(0xffff010101010101));
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}
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TEST(DWARFExpression, DW_OP_convert) {
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/// Auxiliary debug info.
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const char *yamldata = R"(
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--- !ELF
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FileHeader:
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Class: ELFCLASS64
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Data: ELFDATA2LSB
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Type: ET_EXEC
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Machine: EM_386
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DWARF:
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debug_abbrev:
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- Table:
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- Code: 0x00000001
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Tag: DW_TAG_compile_unit
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Children: DW_CHILDREN_yes
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Attributes:
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- Attribute: DW_AT_language
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Form: DW_FORM_data2
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- Code: 0x00000002
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Tag: DW_TAG_base_type
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Children: DW_CHILDREN_no
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Attributes:
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- Attribute: DW_AT_encoding
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Form: DW_FORM_data1
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- Attribute: DW_AT_byte_size
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Form: DW_FORM_data1
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debug_info:
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- Version: 4
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AddrSize: 8
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Entries:
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- AbbrCode: 0x00000001
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Values:
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- Value: 0x000000000000000C
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# 0x0000000e:
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- AbbrCode: 0x00000002
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Values:
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- Value: 0x0000000000000007 # DW_ATE_unsigned
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- Value: 0x0000000000000004
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# 0x00000011:
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- AbbrCode: 0x00000002
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Values:
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- Value: 0x0000000000000007 # DW_ATE_unsigned
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- Value: 0x0000000000000008
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# 0x00000014:
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- AbbrCode: 0x00000002
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Values:
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- Value: 0x0000000000000005 # DW_ATE_signed
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- Value: 0x0000000000000008
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# 0x00000017:
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- AbbrCode: 0x00000002
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Values:
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- Value: 0x0000000000000008 # DW_ATE_unsigned_char
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- Value: 0x0000000000000001
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# 0x0000001a:
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- AbbrCode: 0x00000002
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Values:
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- Value: 0x0000000000000006 # DW_ATE_signed_char
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- Value: 0x0000000000000001
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# 0x0000001d:
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- AbbrCode: 0x00000002
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Values:
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- Value: 0x000000000000000b # DW_ATE_numeric_string
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- Value: 0x0000000000000001
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- AbbrCode: 0x00000000
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)";
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uint8_t offs_uint32_t = 0x0000000e;
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uint8_t offs_uint64_t = 0x00000011;
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uint8_t offs_sint64_t = 0x00000014;
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uint8_t offs_uchar = 0x00000017;
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uint8_t offs_schar = 0x0000001a;
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DWARFExpressionTester t(yamldata);
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ASSERT_TRUE((bool)t.GetDwarfUnit());
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// Constant is given as little-endian.
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bool is_signed = true;
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bool not_signed = false;
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//
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// Positive tests.
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//
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// Leave as is.
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EXPECT_THAT_EXPECTED(t.Eval({DW_OP_const4u, 0x11, 0x22, 0x33, 0x44, //
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DW_OP_convert, offs_uint32_t}),
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llvm::HasValue(GetScalar(64, 0x44332211, not_signed)));
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// Zero-extend to 64 bits.
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EXPECT_THAT_EXPECTED(t.Eval({DW_OP_const4u, 0x11, 0x22, 0x33, 0x44, //
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DW_OP_convert, offs_uint64_t}),
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llvm::HasValue(GetScalar(64, 0x44332211, not_signed)));
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// Sign-extend to 64 bits.
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EXPECT_THAT_EXPECTED(
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t.Eval({DW_OP_const4s, 0xcc, 0xdd, 0xee, 0xff, //
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DW_OP_convert, offs_sint64_t}),
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llvm::HasValue(GetScalar(64, 0xffffffffffeeddcc, is_signed)));
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// Sign-extend, then truncate.
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EXPECT_THAT_EXPECTED(t.Eval({DW_OP_const4s, 0xcc, 0xdd, 0xee, 0xff, //
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DW_OP_convert, offs_sint64_t, //
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DW_OP_convert, offs_uint32_t}),
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llvm::HasValue(GetScalar(32, 0xffeeddcc, not_signed)));
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// Truncate to default unspecified (pointer-sized) type.
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EXPECT_THAT_EXPECTED(t.Eval({DW_OP_const4s, 0xcc, 0xdd, 0xee, 0xff, //
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DW_OP_convert, offs_sint64_t, //
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DW_OP_convert, 0x00}),
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llvm::HasValue(GetScalar(32, 0xffeeddcc, not_signed)));
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// Truncate to 8 bits.
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EXPECT_THAT_EXPECTED(
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t.Eval({DW_OP_const4s, 'A', 'B', 'C', 'D', DW_OP_convert, offs_uchar}),
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llvm::HasValue(GetScalar(8, 'A', not_signed)));
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// Also truncate to 8 bits.
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EXPECT_THAT_EXPECTED(
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t.Eval({DW_OP_const4s, 'A', 'B', 'C', 'D', DW_OP_convert, offs_schar}),
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llvm::HasValue(GetScalar(8, 'A', is_signed)));
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//
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// Errors.
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//
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// No Module.
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EXPECT_THAT_ERROR(Evaluate({DW_OP_const1s, 'X', DW_OP_convert, 0x00}, nullptr,
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t.GetDwarfUnit())
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.takeError(),
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llvm::Failed());
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// No DIE.
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EXPECT_THAT_ERROR(
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t.Eval({DW_OP_const1s, 'X', DW_OP_convert, 0x01}).takeError(),
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llvm::Failed());
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// Unsupported.
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EXPECT_THAT_ERROR(
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t.Eval({DW_OP_const1s, 'X', DW_OP_convert, 0x1d}).takeError(),
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llvm::Failed());
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}
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TEST(DWARFExpression, DW_OP_stack_value) {
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EXPECT_THAT_EXPECTED(Evaluate({DW_OP_stack_value}), llvm::Failed());
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}
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TEST(DWARFExpression, DW_OP_piece) {
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EXPECT_THAT_EXPECTED(Evaluate({DW_OP_const2u, 0x11, 0x22, DW_OP_piece, 2,
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DW_OP_const2u, 0x33, 0x44, DW_OP_piece, 2}),
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llvm::HasValue(GetScalar(32, 0x44332211, true)));
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EXPECT_THAT_EXPECTED(
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Evaluate({DW_OP_piece, 1, DW_OP_const1u, 0xff, DW_OP_piece, 1}),
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// Note that the "00" should really be "undef", but we can't
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// represent that yet.
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llvm::HasValue(GetScalar(16, 0xff00, true)));
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}
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TEST(DWARFExpression, DW_OP_implicit_value) {
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unsigned char bytes = 4;
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EXPECT_THAT_EXPECTED(
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Evaluate({DW_OP_implicit_value, bytes, 0x11, 0x22, 0x33, 0x44}),
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llvm::HasValue(GetScalar(8 * bytes, 0x44332211, true)));
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}
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TEST(DWARFExpression, DW_OP_unknown) {
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EXPECT_THAT_EXPECTED(
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Evaluate({0xff}),
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llvm::FailedWithMessage(
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"Unhandled opcode DW_OP_unknown_ff in DWARFExpression"));
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}
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