The general strategy here is to force use of a thunk when we want to use
default arguments, and have Clang generate uses of the default arguments
on its side of the thunk.
To support this, change the key type used in `clang_decls` from being
just a `Decl*` to being a pair of `Decl*` and number of parameters in
the case of function decls. Import distinct `SemIR::Function`s for each
number of parameters that's used, and corresponding distinct thunks.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
* Rename the type.
* Change lowering to lower FloatLiteralType values as the placeholder
`{}` value we use for literals instead of as an LLVM f64.
* Change eval to convert the type as part of a floating point
conversion, so that lowering can lower converted constants properly.
For now we still represent a value of FloatLiteralType as a
double-precision APFloat. (That will need to change so that we can
losslessly convert literals to f80 / f128 values, and so that we can
convert literals to f32 values without double-rounding.)
When the C++ function has a parameter that is not a pointer and not a
signed integer of 32 or 64 bits, generate a thunk.
Terminology:
* Callee function: The C++ function we actually want to call.
* Thunk function: The C++ function we generated that calls the callee
function.
* A simple ABI type, for now, is one of:
* A pointer
* signed integer with 32 bits
* signed integer with 64 bits
The thunk function is marked `always_inline` and uses the `asm`
attribute to set its mangled to the callee function mangled name
suffixed with `".carbon_thunk"`.
When importing a C++ function, we decide whether calling it requires a
thunk and if so we generate it and import it as well, which is currently
a recursive call.
When calling the thunk function, we initialize a temporary storage for
each non simple ABI parameter type and take its address. This can be
optimized when the variable is already in storage.
Not supported yet:
* Functions with non void return values.
* Member methods.
Moved unsigned int param test from `arithmetic_types_direct.carbon` to
`arithmetic_types_bridged.carbon`, since only signed integers aren't
bridged using a thunk.
C++ Interop Demo:
```c++
// hello_world.h
struct S {
S() {}
S(const S&) { x = 1; }
int x;
};
void hello_world(S s);
```
```c++
// hello_world.cpp
#include "hello_world.h"
#include <cstdio>
void hello_world2(S s) { printf("hello_world2: %d\n", s.x); }
void hello_world(S s) {
printf("hello_world: %d\n", s.x);
hello_world2(s);
}
```
```carbon
// main.carbon
library "Main";
import Cpp library "hello_world.h";
fn Run() -> i32 {
var s : Cpp.S;
Cpp.hello_world(s);
return 0;
}
```
```shell
$ clang -c hello_world.cpp
$ bazel-bin/toolchain/carbon compile main.carbon
$ bazel-bin/toolchain/carbon link hello_world.o main.o --output=demo
$ ./demo
hello_world: 1
hello_world2: 1
```
Before this change (no thunk - copy constructor not called when calling
`hello_world()`):
```shell
$ ./demo
hello_world: -1219172304
hello_world2: 1
```
This is from a quick discussion with zygoloid. There's a mix of uses,
we're both comfortable with a "minimum syntax" decision here to use ADL.
Note this doesn't touch llvm::cast uses in yaml_test_helpers, but ADL
doesn't work there (because the objects are in a `llvm::yaml`
namespace). This gets to another choice made here: if we specify a
namespace, prefer `llvm::` because it's shorter. `clang` has a using of
them, but it's probably better to point at the canonical version if
we're being explicit about it.
Some specific features:
* Use `SpecificFunction` for vtable entries for generic classes.
* Create specific constants for vtable entries in classes derived from
generic classes to reference the appropriate specific of the function
in the context of such a derived class.
* Create specific constants for vtable_ptrs for uses of specific generic
classes.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
This doesn't support actually passing the value of the struct, which is
planned to be implemented using thunks.
`ClangDeclId` value is now `ClangDecl` which includes the mapped Carbon
instruction in addition to the Clang declaration. This allows finding
the Carbon instruction for a given Clang declaration, which is necessary
for mapping a Clang struct parameter type to the Carbon class without
doing name lookup. We don't take the instruction as part of the hash
key, as discussed in
[Discord](https://discord.com/channels/655572317891461132/768530752592805919/1380575881050718469).
To map the type, we also need to map namespaces. To avoid recursion for
inner namespaces, we use a vector.
Note that the first commit just changes the order of functions in the
file to make review easier.
C++ Interop Demo (that shows missing behavior):
```c++
// hello_world.h
struct S {
S(const S&) { x = 1; }
int x;
};
void hello_world(S s);
```
```c++
// hello_world.cpp
#include "hello_world.h"
#include <cstdio>
void hello_world2(S s) { printf("hello_world2: %d\n", s.x); }
void hello_world(S s) {
printf("hello_world: %d\n", s.x);
hello_world2(s);
}
```
```carbon
// main.carbon
library "Main";
import Cpp library "hello_world.h";
fn Run() -> i32 {
var s : Cpp.S;
Cpp.hello_world(s);
return 0;
}
```
```shell
$ clang -c hello_world.cpp
$ bazel-bin/toolchain/carbon compile main.carbon
$ bazel-bin/toolchain/carbon link hello_world.o main.o --output=demo
$ ./demo
hello_world: -1108224096
hello_world2: 1
```
Part of #5533.
This preserves the constant values of the arguments to the thunk, which
is important if the thunk requires conversion of an `IntLiteral` to some
other type. This should become unnecessary once we have form support,
but avoiding the indirection through a thunk function seems valuable
even once that support is in place.
To support this, track whether a function is a thunk on the Function
object, and if so, what the callee of the thunk is. This information is
also included in formatted SemIR when dumping the thunk.
When lowering a specific function whose generic was defined in a
different file, switch to that other file's `FileContext` and lower the
generic there. Also pass the `FileContext` corresponding to the specific
into the `FunctionContext`, and use that `FileContext` for resolving
requests for constants and types from the specific.
- Track the `VarPattern` instruction on the `VarStorage` instruction so
that it's available for name mangling.
- Mangle global variables based on the first binding name within their
pattern.
- Give global variables external rather than internal linkage, except if
they have no bindings whatsoever in their pattern.
- To support lowering references to bindings nested within a global var,
such as for `var (x: i32, b: i32)`, add some basic initial support for
reference constant expressions. Treat a global `var` as a reference
constant, and treat an aggregate access into a reference constant as a
reference constant.
One of the remaining three steps for proof-of-concept virtual function
lowering (the other two being: initializing vptrs to point to these
tables, and using the vptr+table at call sites).
Introduces a (placeholder?) mangling of vtables as ".$vtable" at the end
of the mangling of the class name.
Uses a scheme similar to clang's relative vtables - though those are
relative to the vtable slot, and this is relative to the start of the
vtable (seemed simpler? though I haven't looked at it in detail, perhaps
in lowering call sites I'll find the relative-to-vtable-slot is nicer,
easy enough to change).
Change representation of package names from `IdentifierId` to
`PackageNameId`, and add a special value `PackageNameId::Core` for the
Core package. Add a `Core` expression to name the Core package, and
support for parsing the `Core` keyword in `package` and `import`
declarations.
For now, I've made no changes to instruction fingerprinting or name
mangling. This means that fingerprints and mangled names will collide
between names in the `Core` package and names in a `r#Core` package. See
#4908.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
High level, replacing `Id::Invalid` with `Id::None` and `Id::is_valid`
with `Id::has_value` for clarity, as discussed
[here](https://discord.com/channels/655572317891461132/655578254970716160/1331664574545395794).
The `IntId` refactoring is needed together with `AnyIdBase` because it's
also used with `ValueStore`.
Note, trying to be careful not to rewrite `EnumBase::InvalidIndex`, or
`is_valid` in general (e.g., `IdKind::is_valid`).
I've tried to sequence commits here:
1. Automatic replacements:
- `((?:Id|Index)(?: |::|\(|Base(?:\(|::)))Invalid((?:Index)?\W)` ->
`$1None$2`
- `<invalid>` -> `<none>`
- `InvalidNodeId` -> `NoneNodeId`
- `/\*invalid\*/` -> `/*none*/`
- `id((?:_|\(\))(?:\.|->))is_valid` -> `id$1has_value`
2. Manual edits:
- In `int.h` and `int_test.cpp`
- `IntT` has `is_value`, which I'm renaming to `is_embedded_value`.
- Manual edits to comments in this file.
- `AnyIdBase` and `IdBase`
- Declaration of `is_valid` -> `has_value`, `InvalidIndex` ->
`NoneIndex`.
- In `ids.h` and `ids.cpp`
- `is_valid` -> `has_value`
- `// An explicitly invalid ID.` -> `// An ID with no value.`; similar
for index
- Various math on `InvalidIndex` -> `NoneIndex`
- Various mentions of "valid" in comments
- In `value_store.h`, for `IdT::Invalid`, plus one comment
- In `impl.h` and `tokenized_buffer.h`, we had different initialization
of `::None` values (versus `ids.h` syntax) that I fixed manually.
- Spot checks to compile
- Particularly where `is_valid` replacements didn't catch spots due to
different naming.
3. Autoupdate tests
4. verbose.carbon (NOAUTOUPDATE)
5. Comment spot checks
Note there are probably other mentions of "Invalid" that should be swept
up, but I'd like to argue for merging and separating out remaining
cleanup since this is so sweeping (and likely to hit merge conflicts
from churn). We'll probably have lingering mentions of "invalid" for a
bit regardless, just because there are uses of "invalid" in non-Id APIs.
This adds a RawStringOstream. Versus TestRawOstream, which is
consolidated over to RawStringOstream, it uses a string for storage
instead of a vector, mainly to support move-to-string semantics. Versus
llvm::raw_string_ostream, it owns the string and supports pwrite (which
is needed for driver and its fd_ostream compatibility requirement).
This converts most uses of llvm::raw_string_ostream, leaving behind a
few in InstNamer that explicitly cannot own the string, such as:
```
llvm::raw_string_ostream(name)
<< "_" << tree.tokens().GetColumnNumber(token);
```
I have this as its own library so that it can use CHECK.
Yes this doesn't save much code, but it's code we repeatedly write.
---------
Co-authored-by: Geoff Romer <gromer@google.com>
Instead of including the raw index of the specific, which is unstable
across files and across unrelated changes, use a fingerprint of the
constant values of the specific arguments. This is a placeholder until
we decide on how we want to mangle specific functions.
This is a preparation change for adding name poisoning support
(https://github.com/carbon-language/carbon-lang/issues/4622), which is
expected to require more elaborate logic around NameScope since a name
can be not defined yet, defined, or poisoned.
The API separates looking up a name from getting the full entry since we
have cases where the entries are invalidated between the time we're
looking for the name and when we access (and sometimes modify) the
entry.
This change has the following benefits:
* `names` and `name_map` are internal to `NameScope` and are guaranteed
to match.
* `extended_scopes` and `import_ir_scopes` can not be manipulated (only
new scopes can be added).
* `inst_id`, `name_id` and `parent_scope_id` are constants.
* `has_error` can only be mutated from false to true.
---------
Co-authored-by: jonmeow <jperkins@google.com>
This is stamping out the per-instruction structs, similar to what we do
elsewhere. `BuiltinInstKind::label` then finishes shifting to
`InstKind::ir_name`.
Adds per-builtin instructions, removing `BuiltinInst`. This collapses
`builtin_inst_kind.def` into `inst_kind.def` so that we have a single
place for all macro uses. I still want to remove `BuiltinInstKind`, but
it's something I think is better separated from the `BuiltinInst`
removal.
I'm collapsing the build targets `ids` and `inst_kind` into one because
they both have links to builtin kind information now. It's hard to
separate without a cycle. I'm using the `typed_insts` name because that
seems like the actual most significant thing there, and more interesting
relative to the `inst` target.
For the few remaining uses of the builtin `i32` type, manually build an
`IntType(Signed, 32)` value instead. These are:
- The return type of `Run`.
- The type that int literals in an `if` expression are converted into.
- The type of an array index expression.
We should consider converting those three cases away from `i32` over
time.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
This does a few things:
* Replaces the single `TypeId` in the `FacetTypeInfo` struct with a
vector of `InterfaceId`, `SpecificId` pairs (sorted in id order)
representing the set of interface requirements of the facet type. This
will later be used to support facet types with multiple interface
requirements (as in `I & J` or `I where .Self impls J`).
* Replace `InterfaceType` instructions (used as the type of an
`InterfaceDecl` instruction) with `FacetType` instructions (introduced
in #4460) with a (newly introduced) `FacetTypeFromInterface()` function.
* Replace code that consumed `InterfaceType` values with code that
consumed `FaceType` values. I've generally left the assumption in the
code that it is dealing with a single interface, using the (newly
introduced) `FacetTypeInfo::TryAsSingleInterface`, and producing an
error otherwise. There isn't yet support for the `&` operator or `where
.Self impls`, so this is generally a good assumption for now, except you
can get a facet type with no associated interfaces from a `type
where`... expression. In some cases, the facet type value is pulled from
the evaluation of an `InterfaceDecl` instruction, where the single
interface assumption will hold permanently.
* Some related cleans up: nicer stringification and formatting of facet
types, suppression of some errors when there already was an error.
There is still a lot left to do, including:
* Type `type` should be a facet type with a reserved id, replacing the
built-in instruction.
* Code using `TryAsSingleInterface` should generally be upgraded to
handle more than (or less than) one interface. Name lookup should be
particularly exciting.
* Operator `&` should be defined on facet types, unioning their
interface and other requirements.
* Requirements from a `where` clause don't do anything yet.
* Impls and impl lookup need to resolve facet types, and do things like
determine if all the associated constants are given values.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Geoff Romer <gromer@google.com>
Generate declarations of specific functions on demand. Definitions are
not emitted yet, and I'm using a temporary, known-broken scheme for name
mangling.
This switches `DCHECK` and `FATAL` as well.
The goal is to reduce the code size impact of these assertions so that
we can keep more of them enabled. Currently, the largest cost I see from
`CHECK` is not the actual check or the cold code itself, but actually
the failure to inline trivial functions due to the presence of the cold
code. This means that our goal isn't to reduce apparent code size in the
final binary but the LLVM IR cost assessed for these routines in the
inliner, which closely correlates with code size but is a bit different.
As discussed in #4283, experimentation shows that a single function call
with a minimal number of arguments is the lowest cost model for these.
This is easily achieved with a format-string API that internally uses
`llvm::formatv`. This PR is essentially the `CHECK` version of #4283.
However, the check macros are substantially harder to make work with
both format strings and streaming because they also take a condition.
Also, unexpectedly, I was very successful at devising a regular
expression based automated rewrite from the streaming to the format
string form with only low 10s of manual fixes. This includes compacting
strings broken up across lines, etc. Given how well that went, I've
prepared this PR which just directly switches to the format string API
and migrate everything to use it.
One nice side-effect is that the format string approach ends up greatly
simplifying the implementation here as well.
This is ... *shockingly* effective. Parsing speeds up by more than 3%
with just this change. And checking speeds up by **8%** with this change
alone:
```
BM_CompileAPIFileDenseDecls<Phase::Parse>/256 86.3µs ± 1% 82.9µs ± 1% -3.94% (p=0.000 n=17+19)
BM_CompileAPIFileDenseDecls<Phase::Parse>/1024 431µs ± 1% 415µs ± 1% -3.76% (p=0.000 n=18+19)
BM_CompileAPIFileDenseDecls<Phase::Parse>/4096 1.77ms ± 1% 1.71ms ± 1% -3.18% (p=0.000 n=18+19)
BM_CompileAPIFileDenseDecls<Phase::Parse>/16384 7.44ms ± 1% 7.17ms ± 2% -3.56% (p=0.000 n=18+20)
BM_CompileAPIFileDenseDecls<Phase::Parse>/65536 30.7ms ± 1% 29.7ms ± 1% -3.15% (p=0.000 n=18+20)
BM_CompileAPIFileDenseDecls<Phase::Parse>/262144 131ms ± 1% 127ms ± 1% -2.81% (p=0.000 n=18+18)
BM_CompileAPIFileDenseDecls<Phase::Check>/256 878µs ± 2% 800µs ± 1% -8.91% (p=0.000 n=19+20)
BM_CompileAPIFileDenseDecls<Phase::Check>/1024 1.88ms ± 2% 1.72ms ± 1% -8.56% (p=0.000 n=19+20)
BM_CompileAPIFileDenseDecls<Phase::Check>/4096 5.78ms ± 2% 5.28ms ± 1% -8.70% (p=0.000 n=20+18)
BM_CompileAPIFileDenseDecls<Phase::Check>/16384 21.9ms ± 1% 20.1ms ± 1% -8.02% (p=0.000 n=18+20)
BM_CompileAPIFileDenseDecls<Phase::Check>/65536 90.4ms ± 2% 83.1ms ± 1% -8.04% (p=0.000 n=19+20)
BM_CompileAPIFileDenseDecls<Phase::Check>/262144 381ms ± 2% 352ms ± 1% -7.79% (p=0.000 n=19+19)
```
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
This seems to be enough to avoid naming collisions for functions in any
of the current test cases (verified by asserting that the name of the
`llvm::Function` matches the name passed to create it - not triggering
LLVM's numbering that happens when names collide)
It currently implements mangling for namespace scopes, class scopes, and
impls.
Nothing generic is mangled yet - haven't looked at how that works,
though evidently it's not covered by existing testing, I guess.
Follow-up change will document the current mangling algorithm in
`toolchain/docs/lower.md`
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
Richard SmithandJon Ross-Perkins
Boaz Brickner
David BlaikieandRichard Smith
Thomas Köppe
