Author: bryanpkc Date: Thu May 19 08:51:20 2016 New Revision: 270062 URL: http://llvm.org/viewvc/llvm-project?rev=270062&view=rev Log: Avoid an assertion failure when a bit field is extracted from a value of the same size.
Summary: One of the cases handled by ValueObjectChild::UpdateValue() uses the entire width of the parent's scalar value as the size of the child, and extracts the child by calling Scalar::ExtractBitfield(). This seems valid but APInt::trunc(), APInt::sext() and APInt::zext() assert that the bit field must not have the same size as the parent scalar. Replacing those calls with sextOrTrunc(), zextOrTrunc(), sextOrSelf() and zextOrSelf() fixes the assertion failures. Reviewers: uweigand, labath Subscribers: labath, lldb-commits Differential Revision: http://reviews.llvm.org/D20355 Modified: lldb/trunk/source/Core/Scalar.cpp lldb/trunk/unittests/Core/ScalarTest.cpp Modified: lldb/trunk/source/Core/Scalar.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Core/Scalar.cpp?rev=270062&r1=270061&r2=270062&view=diff ============================================================================== --- lldb/trunk/source/Core/Scalar.cpp (original) +++ lldb/trunk/source/Core/Scalar.cpp Thu May 19 08:51:20 2016 @@ -2788,7 +2788,7 @@ Scalar::ExtractBitfield (uint32_t bit_si case Scalar::e_slonglong: case Scalar::e_sint128: case Scalar::e_sint256: - m_integer = m_integer.ashr(bit_offset).trunc(bit_size).sext(8 * GetByteSize()); + m_integer = m_integer.ashr(bit_offset).sextOrTrunc(bit_size).sextOrSelf(8 * GetByteSize()); return true; case Scalar::e_uint: @@ -2796,7 +2796,7 @@ Scalar::ExtractBitfield (uint32_t bit_si case Scalar::e_ulonglong: case Scalar::e_uint128: case Scalar::e_uint256: - m_integer = m_integer.lshr(bit_offset).trunc(bit_size).zext(8 * GetByteSize()); + m_integer = m_integer.lshr(bit_offset).zextOrTrunc(bit_size).zextOrSelf(8 * GetByteSize()); return true; } return false; Modified: lldb/trunk/unittests/Core/ScalarTest.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/unittests/Core/ScalarTest.cpp?rev=270062&r1=270061&r2=270062&view=diff ============================================================================== --- lldb/trunk/unittests/Core/ScalarTest.cpp (original) +++ lldb/trunk/unittests/Core/ScalarTest.cpp Thu May 19 08:51:20 2016 @@ -79,3 +79,27 @@ TEST(ScalarTest, CastOperations) ASSERT_EQ((unsigned long long)a, a_scalar.ULongLong()); } +TEST(ScalarTest, ExtractBitfield) +{ + uint32_t len = sizeof(long long) * 8; + + long long a1 = 0xf1f2f3f4f5f6f7f8LL; + long long b1 = 0xff1f2f3f4f5f6f7fLL; + Scalar s_scalar(a1); + ASSERT_TRUE(s_scalar.ExtractBitfield(0, 0)); + ASSERT_EQ(0, memcmp(&a1, s_scalar.GetBytes(), sizeof(a1))); + ASSERT_TRUE(s_scalar.ExtractBitfield(len, 0)); + ASSERT_EQ(0, memcmp(&a1, s_scalar.GetBytes(), sizeof(a1))); + ASSERT_TRUE(s_scalar.ExtractBitfield(len - 4, 4)); + ASSERT_EQ(0, memcmp(&b1, s_scalar.GetBytes(), sizeof(b1))); + + unsigned long long a2 = 0xf1f2f3f4f5f6f7f8ULL; + unsigned long long b2 = 0x0f1f2f3f4f5f6f7fULL; + Scalar u_scalar(a2); + ASSERT_TRUE(u_scalar.ExtractBitfield(0, 0)); + ASSERT_EQ(0, memcmp(&a2, u_scalar.GetBytes(), sizeof(a2))); + ASSERT_TRUE(u_scalar.ExtractBitfield(len, 0)); + ASSERT_EQ(0, memcmp(&a2, u_scalar.GetBytes(), sizeof(a2))); + ASSERT_TRUE(u_scalar.ExtractBitfield(len - 4, 4)); + ASSERT_EQ(0, memcmp(&b2, u_scalar.GetBytes(), sizeof(b2))); +} _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
