Author: shafik Date: 2020-07-08T10:07:15-07:00 New Revision: 63b0f8c788d8c6978feb099fd6db8fe219c4d166
URL: https://github.com/llvm/llvm-project/commit/63b0f8c788d8c6978feb099fd6db8fe219c4d166 DIFF: https://github.com/llvm/llvm-project/commit/63b0f8c788d8c6978feb099fd6db8fe219c4d166.diff LOG: [RecordLayout] Fix ItaniumRecordLayoutBuilder so that is grabs the correct bases class offsets from the external source Currently the ItaniumRecordLayoutBuilder when laying out base classes has the virtual and non-virtual bases mixed up when pulling the base class layouts from the external source. This came up in an LLDB bug where on arm64 because of differences in how it deals with tail padding would layout the bases differently without the correct layout from the external source (LLDB). This would result in some fields being off by 4 bytes. Differential Revision: https://reviews.llvm.org/D83008 Added: lldb/test/API/lang/cpp/alignas_base_class/Makefile lldb/test/API/lang/cpp/alignas_base_class/TestAlignAsBaseClass.py lldb/test/API/lang/cpp/alignas_base_class/main.cpp Modified: clang/lib/AST/RecordLayoutBuilder.cpp Removed: ################################################################################ diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp index b44957a35279..d56c7e2ab8c0 100644 --- a/clang/lib/AST/RecordLayoutBuilder.cpp +++ b/clang/lib/AST/RecordLayoutBuilder.cpp @@ -1187,11 +1187,10 @@ ItaniumRecordLayoutBuilder::LayoutBase(const BaseSubobjectInfo *Base) { // Query the external layout to see if it provides an offset. bool HasExternalLayout = false; if (UseExternalLayout) { - // FIXME: This appears to be reversed. if (Base->IsVirtual) - HasExternalLayout = External.getExternalNVBaseOffset(Base->Class, Offset); - else HasExternalLayout = External.getExternalVBaseOffset(Base->Class, Offset); + else + HasExternalLayout = External.getExternalNVBaseOffset(Base->Class, Offset); } // Clang <= 6 incorrectly applied the 'packed' attribute to base classes. diff --git a/lldb/test/API/lang/cpp/alignas_base_class/Makefile b/lldb/test/API/lang/cpp/alignas_base_class/Makefile new file mode 100644 index 000000000000..99998b20bcb0 --- /dev/null +++ b/lldb/test/API/lang/cpp/alignas_base_class/Makefile @@ -0,0 +1,3 @@ +CXX_SOURCES := main.cpp + +include Makefile.rules diff --git a/lldb/test/API/lang/cpp/alignas_base_class/TestAlignAsBaseClass.py b/lldb/test/API/lang/cpp/alignas_base_class/TestAlignAsBaseClass.py new file mode 100644 index 000000000000..25f37ab7fe5f --- /dev/null +++ b/lldb/test/API/lang/cpp/alignas_base_class/TestAlignAsBaseClass.py @@ -0,0 +1,16 @@ +import lldb +from lldbsuite.test.decorators import * +from lldbsuite.test.lldbtest import * +from lldbsuite.test import lldbutil + +class TestCase(TestBase): + + mydir = TestBase.compute_mydir(__file__) + + @no_debug_info_test + def test(self): + self.build() + self.dbg.CreateTarget(self.getBuildArtifact("a.out")) + + # The offset of f2 should be 8 because of `alignas(8)`. + self.expect_expr("(intptr_t)&d3g.f2 - (intptr_t)&d3g", result_value="8") diff --git a/lldb/test/API/lang/cpp/alignas_base_class/main.cpp b/lldb/test/API/lang/cpp/alignas_base_class/main.cpp new file mode 100644 index 000000000000..8dfced6c784e --- /dev/null +++ b/lldb/test/API/lang/cpp/alignas_base_class/main.cpp @@ -0,0 +1,13 @@ +struct B1 { + char f1; +}; + +struct alignas(8) B2 { + char f2; +}; + +struct D : B1, B2 {}; + +D d3g; + +int main() {} _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
