object-introspection/types/string_type.toml
Jake Hillion 55989a9156 oilgen: migrate to source parsing (#421)
Summary:
oilgen: migrate to source parsing

Using debug information generated from partial source (that is, not the final
binary) has been insufficient to generally generate OIL code.

A particular example is pointers to templates:
```cpp
#include <oi/oi.h>
template <typename T>
struct Foo {
  T t;
};
template <typename T>
struct Bar {
  Foo<T>& f;
};
void foo(const Bar<int>& b) {
  oi::introspect(b);
}
```

The pointer/reference to `Foo<int>` appears in DWARF with
`DW_AT_declaration(true)` because it could be specialised before its usage.
However, with OIL, we are creating an implicit usage site in the
`oi::introspect` call that the compiler is unable to see.

This change reworks OILGen to work from a Clang command line rather than debug
information. We setup and run a compiler on the source, giving us access to an
AST and Semantic Analyser. We then:
- Find the `oi::introspect` template.
- Iterate through each of its callsites for their type.
- Run `ClangTypeParser::parse` on each type.
- Run codegen.
- Compile into an object file.

Having access to the semantic analyser allows us to forcefully complete a type,
as it would be if it was used in the initial code.


Test Plan:
hope

`buck2 run fbcode//mode/opt fbcode//object-introspection/oil/examples/compile-time:compile-time`

Reviewed By: tyroguru

Differential Revision: D51854477

Pulled By: JakeHillion
2023-12-19 13:26:25 -08:00

69 lines
1.9 KiB
TOML

[info]
type_name = "std::basic_string"
stub_template_params = [2]
ctype = "STRING_TYPE"
header = "string"
# Old:
typeName = "std::basic_string<"
ns = ["namespace std"]
numTemplateParams = 1
replaceTemplateParamIndex = []
[codegen]
decl = """
template<typename T, typename Traits, typename Allocator>
void getSizeType(const %1%<T, Traits, Allocator> &container, size_t& returnArg);
"""
func = """
template<typename T, typename Traits, typename Allocator>
void getSizeType(const %1%<T, Traits, Allocator> &container, size_t& returnArg)
{
SAVE_SIZE(sizeof(%1%<T>));
SAVE_DATA((uintptr_t)container.capacity());
SAVE_DATA((uintptr_t)container.size());
// Test for small string optimisation - whether the underlying string is
// contained within the string object.
SAVE_SIZE(
((uintptr_t)container.data() < (uintptr_t)(&container + sizeof(%1%<T>)))
&&
((uintptr_t)container.data() >= (uintptr_t)&container)
? 0 : (container.capacity() * sizeof(T))
);
}
"""
traversal_func = """
bool sso = ((uintptr_t)container.data() <
(uintptr_t)(&container + sizeof(std::__cxx11::basic_string<T0>))) &&
((uintptr_t)container.data() >= (uintptr_t)&container);
return returnArg.write(container.capacity())
.write(sso)
.write(container.size());
"""
[[codegen.processor]]
type = "types::st::VarInt<DB>"
func = """
uint64_t capacity = std::get<ParsedData::VarInt>(d.val).value;
el.container_stats.emplace(result::Element::ContainerStats { .capacity = capacity });
"""
[[codegen.processor]]
type = "types::st::VarInt<DB>"
func = """
bool sso = std::get<ParsedData::VarInt>(d.val).value;
if (!sso)
el.exclusive_size += el.container_stats->capacity * sizeof(T0);
"""
[[codegen.processor]]
type = "types::st::VarInt<DB>"
func = """
el.container_stats->length = std::get<ParsedData::VarInt>(d.val).value;
"""