https://github.com/Michael137 updated https://github.com/llvm/llvm-project/pull/96932
>From d2c28706769f89bf9f0b53071726bb59c6205ce8 Mon Sep 17 00:00:00 2001 From: Michael Buch <michaelbuc...@gmail.com> Date: Thu, 27 Jun 2024 17:16:50 +0100 Subject: [PATCH 1/2] [lldb][test] Add test-cases for packed structures Adds test that checks whether LLDB correctly infers the alignment of packed structures. Specifically, the `InferAlignment` code-path of the `ItaniumRecordLayoutBuilder` where it assumes that overlapping field offsets imply a packed structure and thus sets alignment to `1`. See discussion in https://github.com/llvm/llvm-project/pull/93809. While here, also added a test-case where we check alignment of a class whose base has an explicit `DW_AT_alignment (those don't get transitively propagated in DWARF, but don't seem like a problem for LLDB). Lastly, also added an XFAIL-ed tests where the aforementioned `InferAlignment` kicks in for overlapping fields (but in this case incorrectly since the structure isn't actually packed). --- .../TestAlignAsBaseClass.py | 1 + .../API/lang/cpp/alignas_base_class/main.cpp | 7 ++++ .../DWARF/no_unique_address-alignment.cpp | 25 +++++++++++++ lldb/test/Shell/SymbolFile/DWARF/packed.cpp | 36 +++++++++++++++++++ 4 files changed, 69 insertions(+) create mode 100644 lldb/test/Shell/SymbolFile/DWARF/no_unique_address-alignment.cpp create mode 100644 lldb/test/Shell/SymbolFile/DWARF/packed.cpp diff --git a/lldb/test/API/lang/cpp/alignas_base_class/TestAlignAsBaseClass.py b/lldb/test/API/lang/cpp/alignas_base_class/TestAlignAsBaseClass.py index 7d97b0c42b7e1..362fc2740bf52 100644 --- a/lldb/test/API/lang/cpp/alignas_base_class/TestAlignAsBaseClass.py +++ b/lldb/test/API/lang/cpp/alignas_base_class/TestAlignAsBaseClass.py @@ -16,3 +16,4 @@ def test(self): # Verify specified class alignments. self.expect_expr("alignof(B2)", result_value="8") self.expect_expr("alignof(EmptyClassAlign8)", result_value="8") + self.expect_expr("alignof(Derived)", 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 index 9d37554957ba3..a37919deaebdc 100644 --- a/lldb/test/API/lang/cpp/alignas_base_class/main.cpp +++ b/lldb/test/API/lang/cpp/alignas_base_class/main.cpp @@ -13,4 +13,11 @@ D d3g; struct alignas(8) EmptyClassAlign8 { } t; +struct alignas(8) __attribute__((packed)) AlignedAndPackedBase { +} foo; + +struct Derived : AlignedAndPackedBase { +} bar; +static_assert(alignof(Derived) == 8); + int main() {} diff --git a/lldb/test/Shell/SymbolFile/DWARF/no_unique_address-alignment.cpp b/lldb/test/Shell/SymbolFile/DWARF/no_unique_address-alignment.cpp new file mode 100644 index 0000000000000..6e544f40625df --- /dev/null +++ b/lldb/test/Shell/SymbolFile/DWARF/no_unique_address-alignment.cpp @@ -0,0 +1,25 @@ +// XFAIL: * + +// RUN: %clangxx_host -gdwarf -o %t %s +// RUN: %lldb %t \ +// RUN: -o "b main" \ +// RUN: -o "expr alignof(OverlappingFields)" \ +// RUN: -o "expr sizeof(OverlappingFields)" \ +// RUN: -o exit | FileCheck %s + +// CHECK: (lldb) expr alignof(OverlappingFields) +// CHECK-NEXT: ${{.*}} = 4 +// CHECK: (lldb) expr sizeof(OverlappingFields) +// CHECK-NEXT: ${{.*}} = 8 + +struct Empty {}; + +struct OverlappingFields { + char y; + [[no_unique_address]] Empty e; + int z; +} g_packed_struct; +static_assert(alignof(OverlappingFields) == 4); +static_assert(sizeof(OverlappingFields) == 8); + +int main() {} diff --git a/lldb/test/Shell/SymbolFile/DWARF/packed.cpp b/lldb/test/Shell/SymbolFile/DWARF/packed.cpp new file mode 100644 index 0000000000000..fb94a834d48a6 --- /dev/null +++ b/lldb/test/Shell/SymbolFile/DWARF/packed.cpp @@ -0,0 +1,36 @@ +// RUN: %clangxx_host -gdwarf -o %t %s +// RUN: %lldb %t \ +// RUN: -o "b main" \ +// RUN: -o "expr alignof(packed)" \ +// RUN: -o "expr sizeof(packed)" \ +// RUN: -o "expr alignof(packed_and_aligned)" \ +// RUN: -o "expr sizeof(packed_and_aligned)" \ +// RUN: -o exit | FileCheck %s + +// CHECK: (lldb) expr alignof(packed) +// CHECK-NEXT: ${{.*}} = 1 +// CHECK: (lldb) expr sizeof(packed) +// CHECK-NEXT: ${{.*}} = 9 + +// CHECK: (lldb) expr alignof(packed_and_aligned) +// CHECK-NEXT: ${{.*}} = 16 +// CHECK: (lldb) expr sizeof(packed_and_aligned) +// CHECK-NEXT: ${{.*}} = 16 + +struct __attribute__((packed)) packed { + int x; + char y; + int z; +} g_packed_struct; +static_assert(alignof(packed) == 1); +static_assert(sizeof(packed) == 9); + +struct __attribute__((packed, aligned(16))) packed_and_aligned { + int x; + char y; + int z; +} g_packed_and_aligned_struct; +static_assert(alignof(packed_and_aligned) == 16); +static_assert(sizeof(packed_and_aligned) == 16); + +int main() {} >From a7b91858c8f9e09b455a581469155152f2dea11e Mon Sep 17 00:00:00 2001 From: Michael Buch <michaelbuc...@gmail.com> Date: Fri, 28 Jun 2024 09:08:20 +0100 Subject: [PATCH 2/2] fixup! don't set redundant breakpoints --- .../Shell/SymbolFile/DWARF/no_unique_address-alignment.cpp | 3 +-- lldb/test/Shell/SymbolFile/DWARF/packed.cpp | 1 - 2 files changed, 1 insertion(+), 3 deletions(-) diff --git a/lldb/test/Shell/SymbolFile/DWARF/no_unique_address-alignment.cpp b/lldb/test/Shell/SymbolFile/DWARF/no_unique_address-alignment.cpp index 6e544f40625df..1488199a3ad2d 100644 --- a/lldb/test/Shell/SymbolFile/DWARF/no_unique_address-alignment.cpp +++ b/lldb/test/Shell/SymbolFile/DWARF/no_unique_address-alignment.cpp @@ -2,7 +2,6 @@ // RUN: %clangxx_host -gdwarf -o %t %s // RUN: %lldb %t \ -// RUN: -o "b main" \ // RUN: -o "expr alignof(OverlappingFields)" \ // RUN: -o "expr sizeof(OverlappingFields)" \ // RUN: -o exit | FileCheck %s @@ -18,7 +17,7 @@ struct OverlappingFields { char y; [[no_unique_address]] Empty e; int z; -} g_packed_struct; +} g_overlapping_struct; static_assert(alignof(OverlappingFields) == 4); static_assert(sizeof(OverlappingFields) == 8); diff --git a/lldb/test/Shell/SymbolFile/DWARF/packed.cpp b/lldb/test/Shell/SymbolFile/DWARF/packed.cpp index fb94a834d48a6..640a2e0454c92 100644 --- a/lldb/test/Shell/SymbolFile/DWARF/packed.cpp +++ b/lldb/test/Shell/SymbolFile/DWARF/packed.cpp @@ -1,6 +1,5 @@ // RUN: %clangxx_host -gdwarf -o %t %s // RUN: %lldb %t \ -// RUN: -o "b main" \ // RUN: -o "expr alignof(packed)" \ // RUN: -o "expr sizeof(packed)" \ // RUN: -o "expr alignof(packed_and_aligned)" \ _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
