Global variables as type descriptors

[ahueck]

• Type description/type id system for parallel compilation of target codes:
  • file: place user-defined type descriptor in central yaml file (serial compilation needed)
  • hybrid: place type descriptors as globals for user-defined types in each module.
  • inline: also for all (supported) built-in types

Type descriptors

• Types descriptors are placed inside a module as a r/w global. For startup registration with runtime constructor functions are used. Format, 48 bytes per type + members:

struct GlobalTypeInfo {
  std::int32_t type_id;
  const std::uint32_t extent;
  const std::uint16_t num_members;
  const std::uint16_t flag;
  const char* name;
  const std::uint16_t* offsets;
  const std::uint16_t* array_sizes;
  const GlobalTypeInfo** member_types;
};

• Callback:

void __typeart_register_type(const void* type_ptr);

• Globals are parsed at runtime during startup, and the actual type-id is computed and set for each of these globals:

void GlobalTypeTranslator::register_type(const void* type) {
  const auto* info_struct = reinterpret_cast<const GlobalTypeInfo*>(type);
  const auto type_id      = pImpl->register_t(info_struct);
  const_cast<GlobalTypeInfo*>(info_struct)->type_id = type_id;
}

Misc

• Update CI: clang-format-18 on github action runner has bug, use LLVM repo
• Abseil's hashmap clashes with ASan: use std::unordered_map when using ASan and Abseil

ToDos ?

• Save some space by defining the type as, e.g.:

struct GlobalTypeInfo {
  std::int32_t type_id;
  const std::uint32_t extent;
  const std::uint16_t flag;
  const char* name;
  const MemberTypeInfo* info;
};
struct MemberTypeInfo {
  const std::uint16_t num_members;
  const std::uint16_t* offsets;
  const std::uint16_t* array_sizes;
  const GlobalTypeInfo** member_types;
}

[coveralls]

Pull Request Test Coverage Report for Build 19192146139

Details

• 597 of 629 (94.91%) changed or added relevant lines in 25 files are covered.
• 3 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+1.4%) to 90.318%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
lib/runtime/TypeResolution.cpp	15	16	93.75%
lib/passes/TypeARTPass.cpp	26	28	92.86%
lib/runtime/GlobalTypeDefCallbacks.h	4	6	66.67%
lib/typelib/TypeDB.cpp	4	6	66.67%
lib/runtime/GlobalTypeDefCallbacks.cpp	60	64	93.75%
lib/passes/instrumentation/TypeARTFunctions.cpp	100	106	94.34%
lib/runtime/AllocationTracking.cpp	41	56	73.21%

Files with Coverage Reduction	New Missed Lines	%
lib/runtime/AllocationTracking.cpp	1	91.62%
lib/typelib/TypeDB.cpp	1	89.69%
lib/typelib/TypeDB.h	1	94.74%

Totals
Change from base Build 15098967331:	1.4%
Covered Lines:	4767
Relevant Lines:	5278

---

💛 - Coveralls