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Fix nondeterminism in VALIDATE_AND_RETURN caused by comparing uniniti… #3351

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Merged
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Oct 5, 2021
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Fix nondeterminism in VALIDATE_AND_RETURN caused by comparing uniniti… #3351

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22 changes: 15 additions & 7 deletions lldb/source/Plugins/TypeSystem/Swift/TypeSystemSwiftTypeRef.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2490,6 +2490,14 @@ CompilerType TypeSystemSwiftTypeRef::GetChildCompilerTypeAtIndex(
bool &child_is_base_class, bool &child_is_deref_of_parent,
ValueObject *valobj, uint64_t &language_flags) {
LLDB_SCOPED_TIMER();
child_name = "";
child_byte_size = 0;
child_byte_offset = 0;
child_bitfield_bit_size = 0;
child_bitfield_bit_offset = 0;
child_is_base_class = false;
child_is_deref_of_parent = false;
language_flags = 0;
Comment on lines +2493 to +2500
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Why are these reset here? If this is needed, it's missing a #ifndef NDEBUG

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It's because we'll validate them against their ast_* counterparts.
They are initialized unconditionally because the initialization has an effect outside of the function (these are passed in by reference), I really don't want to change LLDB's behavior in asserts/non-asserts build.

auto fallback = [&]() -> CompilerType {
LLDB_LOGF(GetLogIfAllCategoriesSet(LIBLLDB_LOG_TYPES),
"Had to engage SwiftASTContext fallback for type %s.",
Expand Down Expand Up @@ -2648,13 +2656,13 @@ CompilerType TypeSystemSwiftTypeRef::GetChildCompilerTypeAtIndex(

#ifndef NDEBUG
std::string ast_child_name;
uint32_t ast_child_byte_size;
int32_t ast_child_byte_offset;
uint32_t ast_child_bitfield_bit_size;
uint32_t ast_child_bitfield_bit_offset;
bool ast_child_is_base_class;
bool ast_child_is_deref_of_parent;
uint64_t ast_language_flags;
uint32_t ast_child_byte_size = 0;
int32_t ast_child_byte_offset = 0;
uint32_t ast_child_bitfield_bit_size = 0;
uint32_t ast_child_bitfield_bit_offset = 0;
bool ast_child_is_base_class = false;
bool ast_child_is_deref_of_parent = false;
uint64_t ast_language_flags = 0;
auto defer = llvm::make_scope_exit([&] {
if (!ModuleList::GetGlobalModuleListProperties()
.GetSwiftValidateTypeSystem())
Expand Down