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[lldb][TypeSystemClang] Don't create VLAs of explicitly 0-size as IncompleteArrayTypes
1 parent 11a7ee5 commit 59f8a16

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7 files changed

+120
-35
lines changed

7 files changed

+120
-35
lines changed

‎lldb/include/lldb/Symbol/SymbolFile.h‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -211,7 +211,7 @@ class SymbolFile : public PluginInterface {
211211
/// The characteristics of an array type.
212212
struct ArrayInfo {
213213
int64_t first_index = 0;
214-
llvm::SmallVector<uint64_t, 1> element_orders;
214+
llvm::SmallVector<std::optional<uint64_t>, 1> element_orders;
215215
uint32_t byte_stride = 0;
216216
uint32_t bit_stride = 0;
217217
};

‎lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.cpp‎

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -37,7 +37,7 @@ DWARFASTParser::ParseChildArrayInfo(const DWARFDIE &parent_die,
3737
if (attributes.Size() == 0)
3838
continue;
3939

40-
uint64_t num_elements = 0;
40+
std::optional<uint64_t> num_elements;
4141
uint64_t lower_bound = 0;
4242
uint64_t upper_bound = 0;
4343
bool upper_bound_valid = false;
@@ -66,6 +66,7 @@ DWARFASTParser::ParseChildArrayInfo(const DWARFDIE &parent_die,
6666
}
6767
} else
6868
num_elements = form_value.Unsigned();
69+
6970
break;
7071

7172
case DW_AT_bit_stride:
@@ -91,7 +92,7 @@ DWARFASTParser::ParseChildArrayInfo(const DWARFDIE &parent_die,
9192
}
9293
}
9394

94-
if (num_elements == 0) {
95+
if (!num_elements || *num_elements == 0) {
9596
if (upper_bound_valid && upper_bound >= lower_bound)
9697
num_elements = upper_bound - lower_bound + 1;
9798
}

‎lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp‎

Lines changed: 6 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -1395,20 +1395,20 @@ DWARFASTParserClang::ParseArrayType(const DWARFDIE &die,
13951395
uint64_t array_element_bit_stride = byte_stride * 8 + bit_stride;
13961396
CompilerType clang_type;
13971397
if (array_info && array_info->element_orders.size() > 0) {
1398-
uint64_t num_elements = 0;
13991398
auto end = array_info->element_orders.rend();
14001399
for (auto pos = array_info->element_orders.rbegin(); pos != end; ++pos) {
1401-
num_elements = *pos;
1402-
clang_type = m_ast.CreateArrayType(array_element_type, num_elements,
1403-
attrs.is_vector);
1400+
clang_type = m_ast.CreateArrayType(
1401+
array_element_type, /*element_count=*/*pos, attrs.is_vector);
1402+
1403+
uint64_t num_elements = pos->value_or(0);
14041404
array_element_type = clang_type;
14051405
array_element_bit_stride = num_elements
14061406
? array_element_bit_stride * num_elements
14071407
: array_element_bit_stride;
14081408
}
14091409
} else {
1410-
clang_type =
1411-
m_ast.CreateArrayType(array_element_type, 0, attrs.is_vector);
1410+
clang_type = m_ast.CreateArrayType(
1411+
array_element_type, /*element_count=*/std::nullopt, attrs.is_vector);
14121412
}
14131413
ConstString empty_name;
14141414
TypeSP type_sp =

‎lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp‎

Lines changed: 26 additions & 24 deletions
Original file line numberDiff line numberDiff line change
@@ -2233,30 +2233,31 @@ TypeSystemClang::CreateBlockPointerType(const CompilerType &function_type) {
22332233

22342234
#pragma mark Array Types
22352235

2236-
CompilerType TypeSystemClang::CreateArrayType(const CompilerType &element_type,
2237-
size_t element_count,
2238-
bool is_vector) {
2239-
if (element_type.IsValid()) {
2240-
ASTContext &ast = getASTContext();
2236+
CompilerType
2237+
TypeSystemClang::CreateArrayType(const CompilerType &element_type,
2238+
std::optional<size_t> element_count,
2239+
bool is_vector) {
2240+
if (!element_type.IsValid())
2241+
return {};
22412242

2242-
if (is_vector) {
2243-
return GetType(ast.getExtVectorType(ClangUtil::GetQualType(element_type),
2244-
element_count));
2245-
} else {
2243+
ASTContext &ast = getASTContext();
22462244

2247-
llvm::APInt ap_element_count(64, element_count);
2248-
if (element_count == 0) {
2249-
return GetType(
2250-
ast.getIncompleteArrayType(ClangUtil::GetQualType(element_type),
2251-
clang::ArraySizeModifier::Normal, 0));
2252-
} else {
2253-
return GetType(ast.getConstantArrayType(
2254-
ClangUtil::GetQualType(element_type), ap_element_count, nullptr,
2255-
clang::ArraySizeModifier::Normal, 0));
2256-
}
2257-
}
2258-
}
2259-
return CompilerType();
2245+
// Unknown number of elements; this is an incomplete array
2246+
// (e.g., variable length array with non-constant bounds, or
2247+
// a flexible array member).
2248+
if (!element_count)
2249+
return GetType(
2250+
ast.getIncompleteArrayType(ClangUtil::GetQualType(element_type),
2251+
clang::ArraySizeModifier::Normal, 0));
2252+
2253+
if (is_vector)
2254+
return GetType(ast.getExtVectorType(ClangUtil::GetQualType(element_type),
2255+
*element_count));
2256+
2257+
llvm::APInt ap_element_count(64, *element_count);
2258+
return GetType(ast.getConstantArrayType(ClangUtil::GetQualType(element_type),
2259+
ap_element_count, nullptr,
2260+
clang::ArraySizeModifier::Normal, 0));
22602261
}
22612262

22622263
CompilerType TypeSystemClang::CreateStructForIdentifier(
@@ -4767,6 +4768,7 @@ TypeSystemClang::GetBitSize(lldb::opaque_compiler_type_t type,
47674768
clang::QualType qual_type(GetCanonicalQualType(type));
47684769
const clang::Type::TypeClass type_class = qual_type->getTypeClass();
47694770
switch (type_class) {
4771+
case clang::Type::ConstantArray:
47704772
case clang::Type::FunctionProto:
47714773
case clang::Type::Record:
47724774
return getASTContext().getTypeSize(qual_type);
@@ -5457,9 +5459,9 @@ TypeSystemClang::GetNumChildren(lldb::opaque_compiler_type_t type,
54575459
case clang::Type::IncompleteArray:
54585460
if (auto array_info =
54595461
GetDynamicArrayInfo(*this, GetSymbolFile(), qual_type, exe_ctx))
5460-
// Only 1-dimensional arrays are supported.
5462+
// FIXME: Only 1-dimensional arrays are supported.
54615463
num_children = array_info->element_orders.size()
5462-
? array_info->element_orders.back()
5464+
? array_info->element_orders.back().value_or(0)
54635465
: 0;
54645466
break;
54655467

‎lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h‎

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -498,7 +498,8 @@ class TypeSystemClang : public TypeSystem {
498498
// Array Types
499499

500500
CompilerType CreateArrayType(const CompilerType &element_type,
501-
size_t element_count, bool is_vector);
501+
std::optional<size_t> element_count,
502+
bool is_vector);
502503

503504
// Enumeration Types
504505
CompilerType CreateEnumerationType(llvm::StringRef name,

‎lldb/test/API/lang/c/struct_types/main.c‎

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,3 +1,4 @@
1+
// clang-format off
12
struct things_to_sum {
23
int a;
34
int b;
@@ -18,7 +19,7 @@ int main (int argc, char const *argv[])
1819
}; //% self.expect("frame variable pt.padding[0]", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["pt.padding[0] = "])
1920
//% self.expect("frame variable pt.padding[1]", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["pt.padding[1] = "])
2021
//% self.expect_expr("pt.padding[0]", result_type="char")
21-
//% self.expect("image lookup -t point_tag", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ['padding[]'])
22+
//% self.expect("image lookup -t point_tag", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ['padding[0]'])
2223

2324
struct {} empty;
2425
//% self.expect("frame variable empty", substrs = ["empty = {}"])

‎lldb/test/Shell/SymbolFile/DWARF/vla.cpp‎

Lines changed: 80 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,80 @@
1+
// RUN: %clangxx_host -gdwarf -std=c++11 -o %t %s
2+
// RUN: %lldb %t \
3+
// RUN: -o run \
4+
// RUN: -o "frame var --show-types f" \
5+
// RUN: -o "frame var vla0" \
6+
// RUN: -o "frame var fla0" \
7+
// RUN: -o "frame var fla1" \
8+
// RUN: -o "frame var vla01" \
9+
// RUN: -o "frame var vla10" \
10+
// RUN: -o "frame var vlaN" \
11+
// RUN: -o "frame var vlaNM" \
12+
// RUN: -o exit | FileCheck %s
13+
14+
struct Foo {
15+
static constexpr int n = 1;
16+
int m_vlaN[n];
17+
18+
int m_vla0[0];
19+
};
20+
21+
int main() {
22+
Foo f;
23+
f.m_vlaN[0] = 60;
24+
25+
// CHECK: (lldb) frame var --show-types f
26+
// CHECK-NEXT: (Foo) f = {
27+
// CHECK-NEXT: (int[1]) m_vlaN = {
28+
// CHECK-NEXT: (int) [0] = 60
29+
// CHECK-NEXT: }
30+
// CHECK-NEXT: (int[0]) m_vla0 = {}
31+
// CHECK-NEXT: }
32+
33+
int vla0[0] = {};
34+
35+
// CHECK: (lldb) frame var vla0
36+
// CHECK-NEXT: (int[0]) vla0 = {}
37+
38+
int fla0[] = {};
39+
40+
// CHECK: (lldb) frame var fla0
41+
// CHECK-NEXT: (int[0]) fla0 = {}
42+
43+
int fla1[] = {42};
44+
45+
// CHECK: (lldb) frame var fla1
46+
// CHECK-NEXT: (int[1]) fla1 = ([0] = 42)
47+
48+
int vla01[0][1];
49+
50+
// CHECK: (lldb) frame var vla01
51+
// CHECK-NEXT: (int[0][1]) vla01 = {}
52+
53+
int vla10[1][0];
54+
55+
// CHECK: (lldb) frame var vla10
56+
// CHECK-NEXT: (int[1][0]) vla10 = ([0] = int[0]
57+
58+
int n = 3;
59+
int vlaN[n];
60+
for (int i = 0; i < n; ++i)
61+
vlaN[i] = -i;
62+
63+
// CHECK: (lldb) frame var vlaN
64+
// CHECK-NEXT: (int[]) vlaN = ([0] = 0, [1] = -1, [2] = -2)
65+
66+
int m = 2;
67+
int vlaNM[n][m];
68+
for (int i = 0; i < n; ++i)
69+
for (int j = 0; j < m; ++j)
70+
vlaNM[i][j] = i + j;
71+
72+
// FIXME: multi-dimensional VLAs aren't well supported
73+
// CHECK: (lldb) frame var vlaNM
74+
// CHECK-NEXT: (int[][]) vlaNM = {
75+
// CHECK-NEXT: [0] = ([0] = 0, [1] = 1, [2] = 1)
76+
// CHECK-NEXT: [1] = ([0] = 1, [1] = 1, [2] = 2)
77+
// CHECK-NEXT: }
78+
79+
__builtin_debugtrap();
80+
}

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