[Lldb-commits] [lldb] [lldb][TypeSystemClang] Create VLAs of explicitly 0-size as ConstantArrayType (PR #100710)
Michael Buch via lldb-commits
lldb-commits at lists.llvm.org
Fri Jul 26 03:00:50 PDT 2024
https://github.com/Michael137 updated https://github.com/llvm/llvm-project/pull/100710
>From 9136653363bb7fc58e0b7f55a714d36d4613fe24 Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Fri, 26 Jul 2024 01:19:02 +0100
Subject: [PATCH 1/3] [lldb][TypeSystemClang][NFC] Clean up
TypeSystemClang::GetBitSize
This patch does following NFC changes to TypeSystemClang::GetBitSize:
* Factor out the Objective-C logic into a helper function.
* We had a redundant check for `GetCompleteType` in the `RecordType`
case. We can remove that switch case entirely and rely on the
`default` case.
* Introduce a new case for `FunctionProto`. I don't see a good reason
for special-casing this in the `default` case.
* Introduce a new case for `IncompleteArray`.
The motivation for this is that there are a few issues around VLAs
(i.e., `Type::IncompleteArray`) whose fixes will be easier to reason
about after this refactor.
---
.../TypeSystem/Clang/TypeSystemClang.cpp | 114 +++++++++---------
.../TypeSystem/Clang/TypeSystemClang.h | 3 +
2 files changed, 61 insertions(+), 56 deletions(-)
diff --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
index f70efe5ed57e4..3f7a6344542f4 100644
--- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
+++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
@@ -4725,67 +4725,69 @@ TypeSystemClang::GetFloatTypeSemantics(size_t byte_size) {
return llvm::APFloatBase::Bogus();
}
+std::optional<uint64_t>
+TypeSystemClang::GetObjCBitSize(QualType qual_type,
+ ExecutionContextScope *exe_scope) {
+ assert(qual_type->isObjCObjectOrInterfaceType());
+ ExecutionContext exe_ctx(exe_scope);
+ Process *process = exe_ctx.GetProcessPtr();
+ if (process) {
+ if (ObjCLanguageRuntime *objc_runtime =
+ ObjCLanguageRuntime::Get(*process)) {
+ if (std::optional<uint64_t> bit_size =
+ objc_runtime->GetTypeBitSize(GetType(qual_type)))
+ return *bit_size;
+ }
+ } else {
+ static bool g_printed = false;
+ if (!g_printed) {
+ StreamString s;
+ DumpTypeDescription(qual_type.getAsOpaquePtr(), s);
+
+ llvm::outs() << "warning: trying to determine the size of type ";
+ llvm::outs() << s.GetString() << "\n";
+ llvm::outs() << "without a valid ExecutionContext. this is not "
+ "reliable. please file a bug against LLDB.\n";
+ llvm::outs() << "backtrace:\n";
+ llvm::sys::PrintStackTrace(llvm::outs());
+ llvm::outs() << "\n";
+ g_printed = true;
+ }
+ }
+
+ return getASTContext().getTypeSize(qual_type) +
+ getASTContext().getTypeSize(getASTContext().ObjCBuiltinClassTy);
+}
+
std::optional<uint64_t>
TypeSystemClang::GetBitSize(lldb::opaque_compiler_type_t type,
ExecutionContextScope *exe_scope) {
- if (GetCompleteType(type)) {
- clang::QualType qual_type(GetCanonicalQualType(type));
- const clang::Type::TypeClass type_class = qual_type->getTypeClass();
- switch (type_class) {
- case clang::Type::Record:
- if (GetCompleteType(type))
- return getASTContext().getTypeSize(qual_type);
- else
- return std::nullopt;
- break;
+ if (!GetCompleteType(type))
+ return std::nullopt;
- case clang::Type::ObjCInterface:
- case clang::Type::ObjCObject: {
- ExecutionContext exe_ctx(exe_scope);
- Process *process = exe_ctx.GetProcessPtr();
- if (process) {
- if (ObjCLanguageRuntime *objc_runtime =
- ObjCLanguageRuntime::Get(*process)) {
- if (std::optional<uint64_t> bit_size =
- objc_runtime->GetTypeBitSize(GetType(qual_type)))
- return *bit_size;
- }
- } else {
- static bool g_printed = false;
- if (!g_printed) {
- StreamString s;
- DumpTypeDescription(type, s);
-
- llvm::outs() << "warning: trying to determine the size of type ";
- llvm::outs() << s.GetString() << "\n";
- llvm::outs() << "without a valid ExecutionContext. this is not "
- "reliable. please file a bug against LLDB.\n";
- llvm::outs() << "backtrace:\n";
- llvm::sys::PrintStackTrace(llvm::outs());
- llvm::outs() << "\n";
- g_printed = true;
- }
- }
- }
- [[fallthrough]];
- default:
- const uint32_t bit_size = getASTContext().getTypeSize(qual_type);
- if (bit_size == 0) {
- if (qual_type->isIncompleteArrayType())
- return getASTContext().getTypeSize(
- qual_type->getArrayElementTypeNoTypeQual()
- ->getCanonicalTypeUnqualified());
- }
- if (qual_type->isObjCObjectOrInterfaceType())
- return bit_size +
- getASTContext().getTypeSize(getASTContext().ObjCBuiltinClassTy);
- // Function types actually have a size of 0, that's not an error.
- if (qual_type->isFunctionProtoType())
- return bit_size;
- if (bit_size)
- return bit_size;
- }
+ clang::QualType qual_type(GetCanonicalQualType(type));
+ const clang::Type::TypeClass type_class = qual_type->getTypeClass();
+ switch (type_class) {
+ case clang::Type::FunctionProto:
+ case clang::Type::Record:
+ return getASTContext().getTypeSize(qual_type);
+ case clang::Type::ObjCInterface:
+ case clang::Type::ObjCObject:
+ return GetObjCBitSize(qual_type, exe_scope);
+ case clang::Type::IncompleteArray: {
+ const uint64_t bit_size = getASTContext().getTypeSize(qual_type);
+ if (bit_size == 0)
+ return getASTContext().getTypeSize(
+ qual_type->getArrayElementTypeNoTypeQual()
+ ->getCanonicalTypeUnqualified());
+
+ return bit_size;
+ }
+ default:
+ if (const uint64_t bit_size = getASTContext().getTypeSize(qual_type))
+ return bit_size;
}
+
return std::nullopt;
}
diff --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h
index d67b7a4c9fe72..70722eb375ab7 100644
--- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h
+++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h
@@ -1172,6 +1172,9 @@ class TypeSystemClang : public TypeSystem {
/// on creation of a new instance.
void LogCreation() const;
+ std::optional<uint64_t> GetObjCBitSize(clang::QualType qual_type,
+ ExecutionContextScope *exe_scope);
+
// Classes that inherit from TypeSystemClang can see and modify these
std::string m_target_triple;
std::unique_ptr<clang::ASTContext> m_ast_up;
>From 4a0c7552531d23ba573dc7b9fdd5eb66e478bc84 Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Fri, 26 Jul 2024 01:58:54 +0100
Subject: [PATCH 2/3] [lldb][TypeSystemClang] Don't create VLAs of explicitly
0-size as IncompleteArrayTypes
---
lldb/include/lldb/Symbol/SymbolFile.h | 2 +-
.../SymbolFile/DWARF/DWARFASTParser.cpp | 5 +-
.../SymbolFile/DWARF/DWARFASTParserClang.cpp | 12 +--
.../TypeSystem/Clang/TypeSystemClang.cpp | 50 ++++++------
.../TypeSystem/Clang/TypeSystemClang.h | 3 +-
lldb/test/API/lang/c/struct_types/main.c | 3 +-
lldb/test/Shell/SymbolFile/DWARF/vla.cpp | 80 +++++++++++++++++++
7 files changed, 120 insertions(+), 35 deletions(-)
create mode 100644 lldb/test/Shell/SymbolFile/DWARF/vla.cpp
diff --git a/lldb/include/lldb/Symbol/SymbolFile.h b/lldb/include/lldb/Symbol/SymbolFile.h
index d20766788192f..a050a04a5573b 100644
--- a/lldb/include/lldb/Symbol/SymbolFile.h
+++ b/lldb/include/lldb/Symbol/SymbolFile.h
@@ -211,7 +211,7 @@ class SymbolFile : public PluginInterface {
/// The characteristics of an array type.
struct ArrayInfo {
int64_t first_index = 0;
- llvm::SmallVector<uint64_t, 1> element_orders;
+ llvm::SmallVector<std::optional<uint64_t>, 1> element_orders;
uint32_t byte_stride = 0;
uint32_t bit_stride = 0;
};
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.cpp
index 409e9bb37ab28..b3d231604aa44 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.cpp
@@ -37,7 +37,7 @@ DWARFASTParser::ParseChildArrayInfo(const DWARFDIE &parent_die,
if (attributes.Size() == 0)
continue;
- uint64_t num_elements = 0;
+ std::optional<uint64_t> num_elements;
uint64_t lower_bound = 0;
uint64_t upper_bound = 0;
bool upper_bound_valid = false;
@@ -66,6 +66,7 @@ DWARFASTParser::ParseChildArrayInfo(const DWARFDIE &parent_die,
}
} else
num_elements = form_value.Unsigned();
+
break;
case DW_AT_bit_stride:
@@ -91,7 +92,7 @@ DWARFASTParser::ParseChildArrayInfo(const DWARFDIE &parent_die,
}
}
- if (num_elements == 0) {
+ if (!num_elements || *num_elements == 0) {
if (upper_bound_valid && upper_bound >= lower_bound)
num_elements = upper_bound - lower_bound + 1;
}
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
index 85c59a605c675..a4dcde1629fc2 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
@@ -1395,20 +1395,20 @@ DWARFASTParserClang::ParseArrayType(const DWARFDIE &die,
uint64_t array_element_bit_stride = byte_stride * 8 + bit_stride;
CompilerType clang_type;
if (array_info && array_info->element_orders.size() > 0) {
- uint64_t num_elements = 0;
auto end = array_info->element_orders.rend();
for (auto pos = array_info->element_orders.rbegin(); pos != end; ++pos) {
- num_elements = *pos;
- clang_type = m_ast.CreateArrayType(array_element_type, num_elements,
- attrs.is_vector);
+ clang_type = m_ast.CreateArrayType(
+ array_element_type, /*element_count=*/*pos, attrs.is_vector);
+
+ uint64_t num_elements = pos->value_or(0);
array_element_type = clang_type;
array_element_bit_stride = num_elements
? array_element_bit_stride * num_elements
: array_element_bit_stride;
}
} else {
- clang_type =
- m_ast.CreateArrayType(array_element_type, 0, attrs.is_vector);
+ clang_type = m_ast.CreateArrayType(
+ array_element_type, /*element_count=*/std::nullopt, attrs.is_vector);
}
ConstString empty_name;
TypeSP type_sp =
diff --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
index 3f7a6344542f4..411778f490c4b 100644
--- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
+++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
@@ -2233,30 +2233,31 @@ TypeSystemClang::CreateBlockPointerType(const CompilerType &function_type) {
#pragma mark Array Types
-CompilerType TypeSystemClang::CreateArrayType(const CompilerType &element_type,
- size_t element_count,
- bool is_vector) {
- if (element_type.IsValid()) {
- ASTContext &ast = getASTContext();
+CompilerType
+TypeSystemClang::CreateArrayType(const CompilerType &element_type,
+ std::optional<size_t> element_count,
+ bool is_vector) {
+ if (!element_type.IsValid())
+ return {};
- if (is_vector) {
- return GetType(ast.getExtVectorType(ClangUtil::GetQualType(element_type),
- element_count));
- } else {
+ ASTContext &ast = getASTContext();
- llvm::APInt ap_element_count(64, element_count);
- if (element_count == 0) {
- return GetType(
- ast.getIncompleteArrayType(ClangUtil::GetQualType(element_type),
- clang::ArraySizeModifier::Normal, 0));
- } else {
- return GetType(ast.getConstantArrayType(
- ClangUtil::GetQualType(element_type), ap_element_count, nullptr,
- clang::ArraySizeModifier::Normal, 0));
- }
- }
- }
- return CompilerType();
+ // Unknown number of elements; this is an incomplete array
+ // (e.g., variable length array with non-constant bounds, or
+ // a flexible array member).
+ if (!element_count)
+ return GetType(
+ ast.getIncompleteArrayType(ClangUtil::GetQualType(element_type),
+ clang::ArraySizeModifier::Normal, 0));
+
+ if (is_vector)
+ return GetType(ast.getExtVectorType(ClangUtil::GetQualType(element_type),
+ *element_count));
+
+ llvm::APInt ap_element_count(64, *element_count);
+ return GetType(ast.getConstantArrayType(ClangUtil::GetQualType(element_type),
+ ap_element_count, nullptr,
+ clang::ArraySizeModifier::Normal, 0));
}
CompilerType TypeSystemClang::CreateStructForIdentifier(
@@ -4768,6 +4769,7 @@ TypeSystemClang::GetBitSize(lldb::opaque_compiler_type_t type,
clang::QualType qual_type(GetCanonicalQualType(type));
const clang::Type::TypeClass type_class = qual_type->getTypeClass();
switch (type_class) {
+ case clang::Type::ConstantArray:
case clang::Type::FunctionProto:
case clang::Type::Record:
return getASTContext().getTypeSize(qual_type);
@@ -5458,9 +5460,9 @@ TypeSystemClang::GetNumChildren(lldb::opaque_compiler_type_t type,
case clang::Type::IncompleteArray:
if (auto array_info =
GetDynamicArrayInfo(*this, GetSymbolFile(), qual_type, exe_ctx))
- // Only 1-dimensional arrays are supported.
+ // FIXME: Only 1-dimensional arrays are supported.
num_children = array_info->element_orders.size()
- ? array_info->element_orders.back()
+ ? array_info->element_orders.back().value_or(0)
: 0;
break;
diff --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h
index 70722eb375ab7..56a5c0a516706 100644
--- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h
+++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h
@@ -498,7 +498,8 @@ class TypeSystemClang : public TypeSystem {
// Array Types
CompilerType CreateArrayType(const CompilerType &element_type,
- size_t element_count, bool is_vector);
+ std::optional<size_t> element_count,
+ bool is_vector);
// Enumeration Types
CompilerType CreateEnumerationType(llvm::StringRef name,
diff --git a/lldb/test/API/lang/c/struct_types/main.c b/lldb/test/API/lang/c/struct_types/main.c
index e683c49108976..70217c57bec5f 100644
--- a/lldb/test/API/lang/c/struct_types/main.c
+++ b/lldb/test/API/lang/c/struct_types/main.c
@@ -1,3 +1,4 @@
+// clang-format off
struct things_to_sum {
int a;
int b;
@@ -18,7 +19,7 @@ int main (int argc, char const *argv[])
}; //% self.expect("frame variable pt.padding[0]", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["pt.padding[0] = "])
//% self.expect("frame variable pt.padding[1]", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["pt.padding[1] = "])
//% self.expect_expr("pt.padding[0]", result_type="char")
- //% self.expect("image lookup -t point_tag", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ['padding[]'])
+ //% self.expect("image lookup -t point_tag", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ['padding[0]'])
struct {} empty;
//% self.expect("frame variable empty", substrs = ["empty = {}"])
diff --git a/lldb/test/Shell/SymbolFile/DWARF/vla.cpp b/lldb/test/Shell/SymbolFile/DWARF/vla.cpp
new file mode 100644
index 0000000000000..344b100efd9f9
--- /dev/null
+++ b/lldb/test/Shell/SymbolFile/DWARF/vla.cpp
@@ -0,0 +1,80 @@
+// RUN: %clangxx_host -gdwarf -std=c++11 -o %t %s
+// RUN: %lldb %t \
+// RUN: -o run \
+// RUN: -o "frame var --show-types f" \
+// RUN: -o "frame var vla0" \
+// RUN: -o "frame var fla0" \
+// RUN: -o "frame var fla1" \
+// RUN: -o "frame var vla01" \
+// RUN: -o "frame var vla10" \
+// RUN: -o "frame var vlaN" \
+// RUN: -o "frame var vlaNM" \
+// RUN: -o exit | FileCheck %s
+
+struct Foo {
+ static constexpr int n = 1;
+ int m_vlaN[n];
+
+ int m_vla0[0];
+};
+
+int main() {
+ Foo f;
+ f.m_vlaN[0] = 60;
+
+ // CHECK: (lldb) frame var --show-types f
+ // CHECK-NEXT: (Foo) f = {
+ // CHECK-NEXT: (int[1]) m_vlaN = {
+ // CHECK-NEXT: (int) [0] = 60
+ // CHECK-NEXT: }
+ // CHECK-NEXT: (int[0]) m_vla0 = {}
+ // CHECK-NEXT: }
+
+ int vla0[0] = {};
+
+ // CHECK: (lldb) frame var vla0
+ // CHECK-NEXT: (int[0]) vla0 = {}
+
+ int fla0[] = {};
+
+ // CHECK: (lldb) frame var fla0
+ // CHECK-NEXT: (int[0]) fla0 = {}
+
+ int fla1[] = {42};
+
+ // CHECK: (lldb) frame var fla1
+ // CHECK-NEXT: (int[1]) fla1 = ([0] = 42)
+
+ int vla01[0][1];
+
+ // CHECK: (lldb) frame var vla01
+ // CHECK-NEXT: (int[0][1]) vla01 = {}
+
+ int vla10[1][0];
+
+ // CHECK: (lldb) frame var vla10
+ // CHECK-NEXT: (int[1][0]) vla10 = ([0] = int[0]
+
+ int n = 3;
+ int vlaN[n];
+ for (int i = 0; i < n; ++i)
+ vlaN[i] = -i;
+
+ // CHECK: (lldb) frame var vlaN
+ // CHECK-NEXT: (int[]) vlaN = ([0] = 0, [1] = -1, [2] = -2)
+
+ int m = 2;
+ int vlaNM[n][m];
+ for (int i = 0; i < n; ++i)
+ for (int j = 0; j < m; ++j)
+ vlaNM[i][j] = i + j;
+
+ // FIXME: multi-dimensional VLAs aren't well supported
+ // CHECK: (lldb) frame var vlaNM
+ // CHECK-NEXT: (int[][]) vlaNM = {
+ // CHECK-NEXT: [0] = ([0] = 0, [1] = 1, [2] = 1)
+ // CHECK-NEXT: [1] = ([0] = 1, [1] = 1, [2] = 2)
+ // CHECK-NEXT: }
+
+ __builtin_debugtrap();
+}
>From 4cc93e1735286da3962976d65c1b3b827eeeb0fc Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Fri, 26 Jul 2024 11:00:32 +0100
Subject: [PATCH 3/3] fixup! add doxygen comment to element_orders member;
revert redundant whitespace change
---
lldb/include/lldb/Symbol/SymbolFile.h | 8 ++++++++
lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.cpp | 1 -
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/lldb/include/lldb/Symbol/SymbolFile.h b/lldb/include/lldb/Symbol/SymbolFile.h
index a050a04a5573b..8419495da73a2 100644
--- a/lldb/include/lldb/Symbol/SymbolFile.h
+++ b/lldb/include/lldb/Symbol/SymbolFile.h
@@ -211,6 +211,14 @@ class SymbolFile : public PluginInterface {
/// The characteristics of an array type.
struct ArrayInfo {
int64_t first_index = 0;
+
+ ///< Each entry belongs to a distinct DW_TAG_subrange_type.
+ ///< For multi-dimensional DW_TAG_array_types we would have
+ ///< an entry for each dimension. An entry represents the
+ ///< optional element count of the subrange.
+ ///
+ ///< The order of entries follows the order of the DW_TAG_subrange_type
+ ///< children of this DW_TAG_array_type.
llvm::SmallVector<std::optional<uint64_t>, 1> element_orders;
uint32_t byte_stride = 0;
uint32_t bit_stride = 0;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.cpp
index b3d231604aa44..4ed523bbb9e76 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.cpp
@@ -66,7 +66,6 @@ DWARFASTParser::ParseChildArrayInfo(const DWARFDIE &parent_die,
}
} else
num_elements = form_value.Unsigned();
-
break;
case DW_AT_bit_stride:
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