Author: adrian Date: Wed Aug 7 15:40:05 2019 New Revision: 368226 URL: http://llvm.org/viewvc/llvm-project?rev=368226&view=rev Log: Adjust a ValueObjectChild's offset when the child is a bitfield
If a bitfield doesn't fit into the child_byte_size'd window at child_byte_offset, move the window forward until it fits. The problem here is that Value has no notion of bitfields and thus the Value's DataExtractor is sized like the bitfields CompilerType; a sequence of bitfields, however, can be larger than their underlying type. This was not in the big-endian-derived DWARF 2 bitfield attributes because their offsets were counted from the end of the window, so they always fit. rdar://problem/53132189 Differential Revision: https://reviews.llvm.org/D65492 Modified: lldb/trunk/packages/Python/lldbsuite/test/lang/c/bitfields/TestBitfields.py lldb/trunk/packages/Python/lldbsuite/test/lang/c/bitfields/main.c lldb/trunk/source/Core/ValueObjectChild.cpp Modified: lldb/trunk/packages/Python/lldbsuite/test/lang/c/bitfields/TestBitfields.py URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/packages/Python/lldbsuite/test/lang/c/bitfields/TestBitfields.py?rev=368226&r1=368225&r2=368226&view=diff ============================================================================== --- lldb/trunk/packages/Python/lldbsuite/test/lang/c/bitfields/TestBitfields.py (original) +++ lldb/trunk/packages/Python/lldbsuite/test/lang/c/bitfields/TestBitfields.py Wed Aug 7 15:40:05 2019 @@ -146,6 +146,9 @@ class BitfieldsTestCase(TestBase): '(uint8_t:1) b17 = \'\\0\'', ]) + self.expect("v/x large_packed", VARIABLES_DISPLAYED_CORRECTLY, + substrs=["a = 0x0000000cbbbbaaaa", "b = 0x0000000dffffeee"]) + @add_test_categories(['pyapi']) # BitFields exhibit crashes in record layout on Windows Modified: lldb/trunk/packages/Python/lldbsuite/test/lang/c/bitfields/main.c URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/packages/Python/lldbsuite/test/lang/c/bitfields/main.c?rev=368226&r1=368225&r2=368226&view=diff ============================================================================== --- lldb/trunk/packages/Python/lldbsuite/test/lang/c/bitfields/main.c (original) +++ lldb/trunk/packages/Python/lldbsuite/test/lang/c/bitfields/main.c Wed Aug 7 15:40:05 2019 @@ -90,6 +90,14 @@ int main (int argc, char const *argv[]) packed.b = 10; packed.c = 0x7112233; + struct LargePackedBits { + unsigned long a: 36; + unsigned long b: 36; + } __attribute__((packed)); + + struct LargePackedBits large_packed = + (struct LargePackedBits){ 0xcbbbbaaaa, 0xdffffeeee }; + return 0; //// Set break point at this line. } Modified: lldb/trunk/source/Core/ValueObjectChild.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Core/ValueObjectChild.cpp?rev=368226&r1=368225&r2=368226&view=diff ============================================================================== --- lldb/trunk/source/Core/ValueObjectChild.cpp (original) +++ lldb/trunk/source/Core/ValueObjectChild.cpp Wed Aug 7 15:40:05 2019 @@ -175,6 +175,30 @@ bool ValueObjectChild::UpdateValue() { // Set this object's scalar value to the address of its value by // adding its byte offset to the parent address m_value.GetScalar() += GetByteOffset(); + + // If a bitfield doesn't fit into the child_byte_size'd + // window at child_byte_offset, move the window forward + // until it fits. The problem here is that Value has no + // notion of bitfields and thus the Value's DataExtractor + // is sized like the bitfields CompilerType; a sequence of + // bitfields, however, can be larger than their underlying + // type. + if (m_bitfield_bit_offset) { + const bool thread_and_frame_only_if_stopped = true; + ExecutionContext exe_ctx(GetExecutionContextRef().Lock( + thread_and_frame_only_if_stopped)); + if (auto type_bit_size = GetCompilerType().GetBitSize( + exe_ctx.GetBestExecutionContextScope())) { + uint64_t bitfield_end = + m_bitfield_bit_size + m_bitfield_bit_offset; + if (bitfield_end > *type_bit_size) { + uint64_t overhang_bytes = + (bitfield_end - *type_bit_size + 7) / 8; + m_value.GetScalar() += overhang_bytes; + m_bitfield_bit_offset -= overhang_bytes * 8; + } + } + } } } break; _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
