Commit Graph
110 Commits
Author SHA1 Message Date
Dana Jansens f51c075f8b Avoid symbolic witnesses for .Self in an impl decl (#7564)
Point symbolic witnesses into `.Self` written inside an impl decl at the
impl that is being declared. This is tricky because the impl does not
yet exist. So we use a new instruction `ImplSelfWitness` which _will_ be
replaced by the `ImplWitness` once it becomes available. The
`ImplSelfWitness` acts like a symbolic witness, except it does not
perform lookup, since we know which impl we will get a witness from.

This prevents us from finding other impls when performing lookups into
`.Self` in an impl decl, which produces incorrect/incoherent results.
2026-07-29 16:25:23 +00:00
Richard SmithandGeoff Romer 6e62a7d4a2 Destroy locals at the end of blocks, not only on return (#7448)
Destroy local variables and temporaries at each `}`, and when branching
with `break` and `continue`. In `for` statements, destroy loop variables
along with anything created within the loop at the end of each loop
iteration, and destroy the cursor and range object when the loop
terminates.

Assisted-by: Gemini via Antigravity

---------

Co-authored-by: Geoff Romer <gromer@google.com>
2026-07-14 00:59:22 +00:00
Dana Jansens 4261bb2dd2 Track and don't replace active .Self (#7443)
In #7436 we stopped substituting `.Self` when collecting witnesses out
of a facet type. While this was correct, it did not capture all the
cases that need to avoid substituting `.Self`. And it poisoned the
`IdentifiedFacetType` cache by not replacing `.Self` but storing the
result in the cache. This led to incoherent behaviour, where the result
of an impl lookup would change depending on which ones had been done
previously.

Now we use a flag to track for each `.Self` if we're currently
type-checking inside the scope where it was introduced in a facet type.
While inside that scope, identify should not replace the `.Self`. Any
use of it should remain as-is since we don't yet know what value will
replace it. We call this state "frozen" since it should not be modified
by identify. This requires a substitution step when we leave the scope
that introduced the `.Self`, to remove the flag. The flag is set in the
`EntityName` of the `SymbolicBinding`, and is part of the canonical
value, since `.Self` can become part of types, which are constants, and
the flag needs to follow it for correct behaviour.

We also have to ensure the flag is the same when doing comparison with
constants from inside a facet type and constants from outside. For
instance in `(Z where .Z1 = ()) where .Z2 = .Z1`, when we arrive at the
second `.Z1` its `.Self` will be frozen, while the `.Z1 = ()` contains a
non-frozen `.Self`. So we add the frozen flag to the first when storing
it in `where_stack` in order to compare the constant values of the two
`.Z1`.

The `WhereExpr` requirement inst kinds now have an `InstConstantKind` of
`AlwaysUnique` instead of `Never`. This allows us to add them to the
usual InstBlocks, and in an `eval fn` body they have a constant value,
so eval does not fail when trying to call that function. We have to be
careful to not consider `AlwaysUnique` as being actually concrete
though, since their constant value erases `.Self`-dependence. This
allows us to stop special casing them when thawing the requirements
block in a `WhereExpr`, and we can just thaw each `InstId` in the block
in a straightforward manner.

We add the new flag to the instruction's fingerprint and name in
formatted semir.
2026-07-08 18:04:56 +00:00
Geoff Romer ae3c4266d4 Add separators between files in LLVM IR dumps (#7463)
Each file dump now starts with a `; ---` comment and ends with a blank
line. This makes it easier to visually scan the dump for a file of
interest. The comment format is somewhat arbitrary; I chose `---` to
align with the `--- filename.carbon` separator in SemIR dumps, but
without the filename, because that appears on each of the next two lines
already.
2026-07-07 16:31:24 +00:00
David Blaikie 88b3605eac Fix #7289: Add debug info module flags as-needed and verify if already present (#7336)
This avoids duplicate module flags when compiling C++ interop with debug
info.

Assisted-by: Gemini via Antigravity
2026-06-16 03:18:05 +00:00
Geoff RomerandRichard Smith e023f75254 Implement thunking in terms of constant evaluation (#7332)
The bulk of this change is changing most pattern insts to be `Always`
rather than `AlwaysUnique` constants, so that they can be wrapped in
`SpecificConstant`s to perform substitution. That then lets thunking
rely much more on `SpecificConstant` wrappers instead of deep-copying
the inst tree with modified types.

This approach to thunking should scale better, particularly as things
like form generics make function signatures more complex, because we can
leverage the existing support for constant evaluation and substitution.
Unfortunately, applying this approach to binding patterns will require
more work; see the TODO near the top of `thunk.cpp` for details.

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2026-06-13 00:22:00 +00:00
Richard Smith 25e72882fc Implement Core.CharLiteral operations from #6710 and #7314 (#7316)
Adds support for arithmetic and comparison operators on
`Core.CharLiteral`s, as well as conversions between `CharLiteral` and
integer types.

Make some minor tweaks to fix skill issues encountered while making this
change.

Assisted-by: Gemini via Antigravity
2026-06-11 16:45:39 +00:00
Chandler Carruthandjosh11b 7871237c15 Move self to the explicit () parameter list (proposal #7016) (#7272)
Implements proposal #7016: `self` moves from the deduced implicit list
(`fn F[self: Self]()`) to the front of the explicit list. Its type may
be written explicitly (`fn F(self: Self)`) or omitted, in which case it
defaults to `Self` (`fn F(self)`, `fn F(ref self)`); `self` in the
implicit list is rejected.

Throughout checking, `self` is modeled as the first explicit parameter.
Because a method is just a function whose first parameter is `self`, it
can also be called as an ordinary function with the receiver passed
explicitly (`Type.M(obj, ...)`), not only as `obj.M(...)`. A new
`SemIR::CallArgParamPatterns` helper chooses the parameters matched
against the explicit arguments, excluding a leading `self` only when it
is supplied as a method-call receiver; arity checking, conversion, and
generic deduction use it. The resulting SemIR and lowering are
unchanged: `self` is still `call_param0`, and witnesses, thunks, and
vtables are unaffected.

An omitted `self` type is parsed as a `SelfBindingPattern` node with no
type expression; checking synthesizes the `Self` type so it behaves
exactly like `self: Self`. However, the exact spelling used must match
between a forward declaration and a definition, following #3763's rules
around declaration matching.

Generated functions, thunks, and C++ interop import/export build `self`
as the first explicit parameter, and the `self`-type override (e.g.
Derived->Base for a virtual override) applies to the explicit `self`.
Placement is validated by new diagnostics: `SelfInImplicitParamList`,
`SelfNotFirstParam`, and `SelfOutsideParamList`. The benchmark source
generator and the documentation adopt the `(self)` shorthand; the
prelude, the examples, and the test data are migrated in the following
commits.

Assisted-by: Claude Code with Claude Opus 4.7

---------

Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
2026-06-10 15:30:43 +00:00
Christopher Di Bella eaf16a5250 Adapters should only be destroyable if their adapted type is destroyable (#7271)
Adapters were erroneously satisfying `Core.Destroy` because we were
directly getting the object's representation without consideration for
abstract and adapted types. This change ensures that adapted types'
representations are used instead of the adapter types.
2026-06-10 00:48:33 +00:00
Richard Smith cefa0397bb More fixes to package and library fingerprinting. (#7297)
Fix import logic to make all imported packages be children of the
`NameScopeId::Package` scope. Previously, indirectly-imported packages
would end up as children of their importing package's scope, which
resulted in them not being treated as packages at all, and in particular
not being fingerprinted as packages.

Fixing that caused a failure in the fingerprinting logic as we started
to encounter packages with no correspoding import scopes. Instead of
looking for import scopes, use a simpler mechanism to map packages to
their package names, and clean up.

Unfortunately the latter change churns all the fingerprints again :(
Hopefully this is the last time for a while.
2026-06-04 17:41:46 +00:00
Richard Smith c69b882379 Fix crash lowering reference return. (#7301)
Fix a lowering crash when lowering a return by reference of a type with
an in-place initializing representation. We previously misinterpreted
this as an in-place initializing return.

This is addressed by changing lowering to interpret a `ReturnExpr` of a
reference expression as a reference return. However, that exposes
another issue: `return var;` produces a `ReturnExpr` of a reference
expression in the case where it returns in place! To fix that, we switch
`return var;` to producing a `ReturnExpr` of a value expression
regardless of whether the function has a return slot. This makes the
representation of `return var;` more uniform:

* If the expression is a reference, we're performing a `ref` return.
* If the expression is an initializing expression, we're performing a
normal by-initialization return.
* If the expression is a value expression, we're performing a `return
var;`.
2026-06-04 15:51:28 +00:00
Richard Smith 7fe3e35aec Support for float <-> int conversions. (#7275)
Implement support for floating-point <-> integer type conversions as
described in #820 and #845, extended to support `unsafe as` conversions
for the conversions that can't be expressed as either implicit
conversions or `as` conversions.

One tricky part here is conversions from floating-point literals to
integer types. Such literals may have both a very large mantissa and a
corresponding somewhat large negative exponent, and still produce a
result that is in the range of values that a small integer type can
represent. In order to support that while avoiding building very large
2^N or 10^N constants in general, we first compute a conservative
approximation of the number of bits necessary to represent the integer
result, with an early exit if the number is either definitely too large
or definitely zero. The remaining cases have a reasonable bound on the
size of integer necessary to compute the base^exponent multiplicand.

Assisted-by: Gemini via Antigravity
2026-06-03 23:41:20 +00:00
Richard Smith f5e9c61f11 Don't include the library name in most fingerprints. (#7292)
When we import from another library in the same package, its entities
end up with our library as their parent scope, resulting in cross-file
fingerprint mismatches. Instead, only include the library ID when
fingerprinting either a package-private entity or an `ImportIRId` that
refers to a particular `SemIR::File`.
2026-06-02 19:31:30 +00:00
Richard Smith b7f11e4c61 Propagate Carbon type alignments into LLVM IR. (#7290)
Use the Carbon-computed alignment for allocas, loads, stores, and
memcpys. Previously we used whatever LLVM felt like giving us, which
would result in ABI mismatches and runtime crashes due to misalignment
when creating objects of imported C++ class types, as well as resulting
in some surprising choices like `(i32, i32)` and `()` having 8-byte
alignment instead of 4 and 1, respectively.
2026-06-02 01:35:03 +00:00
Richard Smith 49e5e15138 Fix mangling collisions for library-private entities. (#7283)
Include the library name in the fingerprint of an entity declared
`private` at namespace scope. Include the entity's fingerprint in the
mangling of a library-private entity.

This fixes miscompiles if two libraries in the same package declare
`private` entites with the same name. We can't fix this with internal
linkage because library-private entities can be reachable through
generics defined in the API file of the library.

Assisted-by: Gemini via Antigravity
2026-06-01 19:19:08 +00:00
Richard Smith 09d1331e85 Make Optional(T) copyable. (#7268)
`Optional` is already restricted to only be able to store copyable
types, so it should always implement `Core.Copy`.
2026-05-27 18:13:26 +00:00
Richard Smith 05cc09daca Fix cross-package signature mismatches. (#7232)
Fixes link failures when referencing a symbol involving a fingerprint
from a different package.

Previously we included the `Namespace`'s `import_id` as part of its
fingerprint, which caused local and imported namespaces to get different
fingerprints. We now store the `import_id` on the `NameScope` instead of
on the `Namespace` inst to avoid this problem.

Also, when we reach a package-level `NameScopeId`, consistently
fingerprint it as a (package name, library name) pair. Previously the
fingerprinting depended on whether it was imported or not, as an
imported `NameScopeId` had a parent scope (the current package). We need
to include the library name here so that private entities with the same
name in different libraries have different fingerprints.
2026-05-21 00:02:29 +00:00
josh11bandJosh L 832d46f01b Update LLVM (#7221)
Assisted-by: Google Antigravity

---------

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
2026-05-18 17:06:58 +00:00
Lucile Rose Nihlen bc1ae703c3 return 0 from Run when it doesn't specify a return value (#7180)
https://carbon.compiler-explorer.com/z/88K9Kh5Wo shows the program
exiting with a garbage value copied from uninitialized memory.

This PR modifies `lower` to detect if the function lowered is the
entry point and doesn't specify a return type. If so, it emits
different LLVM IR to return int32 0, and modifies the lowered
function signature to match the int32 return type.
2026-05-08 19:00:47 +00:00
Richard Smith bc06f6c5ec Mangle the signature decl when mangling a thunk. (#7177)
Fixes mangling collisions when two thunks with the same name (eg, `Op`)
are created in the same context, which in turn would lead to LLVM
verifier failures and miscompiles.

To support this, add a new value store to track a little more
information about thunks beyond what's in the `Function`.
2026-05-07 21:58:29 +00:00
Dana Jansens f8dd4d85bf Do not treat impls in different scopes as redeclarations (#7161)
An impl in a different scope, with the same parameters, will overlap and
get diagnosed for that later by the [prioritization
rule](https://docs.carbon-lang.dev/docs/design/generics/details.html#prioritization-rule),
if they are not in a match_first block. But they are not considered as
redeclarations.

See [proposal
p5366](https://github.com/carbon-language/carbon-lang/blob/62b94f79322039acc3fc8e175896a64a32df470e/proposals/p5366.md)
for the rule.
2026-05-04 19:11:51 +00:00
Dana Jansens 554b1b8d10 Remove SymbolicBindingType (#7114)
This inst was meant to support tracking the depth of a `.Self` facet,
but we have now implemented substitution of `.Self` in facet type
identification, and in eval of where expressions, without needing to
track the depth.

See history here:
-
[2025-06-30](https://docs.google.com/document/d/1Yt-i5AmF76LSvD4TrWRIAE_92kii6j5yFiW-S7ahzlg/edit?tab=t.0#heading=h.4qd5dkyfn2k3)
-
[2025-07-07](https://docs.google.com/document/d/1Yt-i5AmF76LSvD4TrWRIAE_92kii6j5yFiW-S7ahzlg/edit?tab=t.0#heading=h.7urbxcq23olv)
- #6026
2026-04-27 19:04:59 +00:00
Richard Smith a6061d975c Compute type layouts in SemIR / Check (#7066)
Instead of allowing lower to pick whatever type layout it desires,
compute the layouts of types as part of completing the type, and make
lower build types that match that representation.

For now we assume that all pointers are 64-bit, since we don't have
access to target information. We allow tail padding reuse for structs
and tuple types (and by extension, for classes, since they use structs
as their object representation), but not for arrays.

In order to build matching LLVM types, we create LLVM packed structs
where necessary, and we insert inter-field padding on the end of the
previous field so that GEP indexes still always match Carbon's
ElementIndexes.

We don't yet use the computed alignment much in LLVM IR generation -- in
particular, `alloca`s, `load`s, and `store`s should probably use the
computed type alignment, but don't.

Assisted-by: Gemini via Antigravity
2026-04-16 22:37:48 +00:00
Richard Smith 8e0d856725 Improve InPlaceInitializing conversion. (#7021)
Fix some situations where we'd drop the storage argument when building
an in-place initializing expression. We now guarantee that an expression
with the in-place initializing category always has a storage argument.
2026-04-03 21:28:54 +00:00
Jon Ross-Perkinsandjonmeow 9266ced4e3 Improve CanDestroyType to handle remaining cases (#6943)
This is only fixing the decision about *whether* to produce a witness.
Implementation of the witness is still a TODO, though where a body is
generated, it should also precisely reflect where one _needs_ to be
generated.

Note the tests:

- toolchain/lower/testdata/function/generic/import_core_witness.carbon
- toolchain/lower/testdata/function/generic/import_unused_def.carbon

These tests can probably be produced _without_ Core.Destroy, but I found
the essence of them while trying to build //examples with Core.Destroy
and a simpler minimization wasn't striking me.

Assisted-by: Google Antigravity with Gemini

---------

Co-authored-by: jonmeow <jperkins@google.com>
2026-04-02 22:54:58 +00:00
Richard Smith dfac728571 Fix pointer sizes in debug info. (#7002)
The size is in bits, so 8 is an unlikely value. Also, don't hardcode a
size, ask the data layout for it.
2026-04-01 16:35:12 +00:00
Nicholas Bishop 396756c151 Handle Temporary values when const-evaling AcquireValue (#6992)
This will be used for const-evaling functions. Splitting into a separate
commit since it touches a lot of test files, and a couple fail_todo
tests are no longer failing.
2026-03-31 15:50:54 +00:00
Nicholas Bishop bf6a14ac39 Support Temporary constants (#6983)
Evaluate `Temporary` constants to a `Temporary` with the `storage` field
set to `None`.
2026-03-30 19:07:46 +00:00
Richard SmithandGeoff Romer ce50f181f1 Add an interface for initialization of vars without an explicit initializer (#6934)
When a `var` is not explicitly given an initializer, initialize it in
one of two ways:

* If its type implements the new interface `Core.Default`, call
`Core.Default.Op` to initialize it.
* Otherwise, if its type implements `UnformedInit`, leave it in an
unformed state. For now, this is always an uninitialized state, but that
will change in the future.
* If neither of those apply, the `var` declaration is ill-formed.

This is a step towards implementing leads decision #6739 and proposals
#257 and #5913.

Assisted-by: Gemini 3.1 Pro via Antigravity

---------

Co-authored-by: Geoff Romer <gromer@google.com>
2026-03-19 23:46:06 +00:00
Richard Smith c297344937 Support conversion between integer types. (#6856)
Add an `IntFitsIn` interface with a custom witness, such that `T impls
IntFitsIn(U)` if `T` is an integer type all of whose values fit
losslessly into the integer type `U`. Use it to constrain implicit
conversions between integer types.

So far, this has not been extended to the
`CppCompat.[U]{Long32,LongLong64}` types, only to `Core.Int(N)` and
`Core.UInt(N)`.

Assisted-by: Gemini 3 Pro via Antigravity
2026-03-10 01:40:16 +00:00
Jon Ross-Perkins b14015602b Make Destroy.Op functions able to have a body (#6729)
This is iterating on how `Destroy.Op` generates, to start adding body
capabilities. This changes the way the signature is created, and adds a
`CoreWitness` function kind so that mangling can prevent name
collisions. The result is that what _was_ `DestroyOp` is now
`Core.Destroy.Op` or, as can be seen in
toolchain/lower/testdata/interop/cpp/nullptr.carbon,
`_COp.<hash>:core.Destroy.Core` where `:core` is indicating that it's a
core witness (taking a note from `:thunk`).

Assisted-by: Google Antigravity with Gemini 3 Flash
2026-03-02 17:57:31 +00:00
fdb188ccfd Implement unused pattern bindings, continued (#6518)
Implementation of unused pattern bindings #2022, continued.

Whereas previous PR #6460 took care of parsing, and PR #6479 prepared
the stage by using _ in some test cases, this PR has the the actual
implementation, using a simple dataflow analysis.

---------

Co-authored-by: Burak Emir <bqe@google.com>
Co-authored-by: jonmeow <jperkins@google.com>
2026-02-19 23:33:36 +00:00
Richard Smith 8353965ca3 Allow conversions between all pointer types with unsafe as. (#6635)
Previously we only allowed conversions from `void*` to `U*` this way,
requiring casting via `void*` to get from `T*` to `U*`. That seems like
an unnecessary circumlocution.
2026-01-21 15:47:51 +00:00
Richard Smith 31919afa24 Allow conversion between T* and Cpp.void*. (#6575)
Support an implicit conversion from `T*` to `Cpp.void*` and to `const
Cpp.void*`, and an `unsafe as` conversion in the opposite direction.

In order to support C++ calls taking and returning `void*` (which get
mapped to Carbon `Optional(Cpp.void*)`, also support conversions from
`Optional(T)` to `Optional(U)` if there's a conversion from `T` to `U`.

Fix a bug in `OptionalStorage` for `T*` where its `HasValue` was exactly
backwards.
2026-01-12 16:32:15 +00:00
Özgür 29018f38a6 Fix name mangling of generic impls (#6533)
### Description
Mangling collisions occur when implementing interfaces with generic
parameters. The mangler does not use the specific id, causing the same
symbol `_C[FunctionName].[PackageName]:[InterfaceName].[PackageName]` to
be generated for all of the implementations below:
```carbon
// Generic interface parameters ignored
impl C as I(A)
impl C as I(B)

// Generic class parameters ignored
impl D(A) as I
impl D(B) as I

// Both ignored
impl D(A) as I(A)
impl D(B) as I(B)
```

### Changes
Updated the mangling logic for `SemIR::ClassDecl` and
`SemIR::InterfaceDecl` to include the specific id. Now the mangling
ensures unique symbols for generic implementations using the format:

`_C[FunctionName].[FunctionSpecificId].[PackageName]:[InterfaceName].[InterfaceSpecificId].[PackageName]`.

Closes #6498
2025-12-23 00:36:03 +00:00
Jon Ross-Perkins c5eba90317 Change Destroy to use a CustomWitness instead of a blanket impl (#6512)
Pursuant to recent decisions on #6124, switch `Destroy` to use a
`CustomWitness` for its implementation. Right now this is manufacturing
no-op implementation functions on each lookup, which obviously isn't
ideal but is intended as a first pass. I'm mostly trying to find the
right balance between updating the approach to reflect new decisions,
while still breaking apart work in a way.

The `CoreInterface` logic is intended to build on `CoreIdentifier`
support. We have a number of additional interfaces that require
specialized logic, and that'll extend pretty far with C++ interop, so it
seemed easiest to have a generic function for it. That's what's
replacing the logic inside C++ interop that was doing string comparisons
(which could have already been moved to `CoreIdentifier`, I just missed
it in my first pass).

This adds `CustomWitness` support because the `Destroy` witnesses can be
imported cross-file. `CustomWitness` was previously only used for C++
types, which don't yet support import, which is why that wasn't
previously an issue. The addition of `query_specific_interface_id` is
similarly needed in order to get correct sorting of witness blocks when
imported.

This PR also removes builtin constraint logic (note this is in a
separate commit to help review; it's not a separate PR because it's
difficult to split apart without tests breaking). This had been made
generic with the expectation that destroy, copy, move, and conversions
would all need related support. Under the new decision, we are not going
to do blanket impls and will instead just manufacture a `CustomWitness`
for everything.

A lot of SemIR fingerprints change, but that's probably because the
addition of `Destroy` on core classes is yielding structural changes.
2025-12-19 18:36:06 +00:00
Burak Emir 992d435023 Replace unused bindings with anonymous binding in lower/testdata. (#6479)
This updates lower/testdata to use _ instead of proper names, in order
to avoid the "unused binding" warnings from #2022 which are being
implemented. These changes do not depend on the implementation which
should make everything easier to review.

See #6460 with part 1 of the implementation. It was split upon request
in order to make reviewing easier, the original state of the PR was
updating hundreds of test cases.
The PR has thus been split, part 2 including test cases changes can be
viewed at
https://github.com/burakemir/carbon-lang/tree/unused_pattern_bindings_p2022_impl_part2
... many tests need to be updated, so it seems best to get those tests
out of the way that are not interesting.

These are not all tests in lower/testdata - a few of them are
interesting in the sense that they cannot use '_' because it leads to
failed redeclaration check. This is exactly the scenario described in
#3763 which requires the 'unused' marker. Those are left untouched here
but are updated in
https://github.com/burakemir/carbon-lang/tree/unused_pattern_bindings_p2022_impl_part2
2025-12-17 15:43:04 +00:00
Jon Ross-Perkins 47e551141f Change the package namespace to use the package name (#6495)
Instead of naming the root namespace `package` (because it's accessed by
the `package` keyword), change it to use the current package name. Note,
buried in the checksum changes,
`toolchain/check/testdata/package_expr/fail_not_found.carbon`:

```
-  // CHECK:STDERR: fail_not_found.carbon:[[@LINE+4]]:16: error: member name `x` not found in `package` [MemberNameNotFoundInInstScope]
+  // CHECK:STDERR: fail_not_found.carbon:[[@LINE+4]]:16: error: member name `x` not found in `Main` [MemberNameNotFoundInInstScope]
```

for:

```
  // CHECK:STDERR:   var y: i32 = package.x;
  // CHECK:STDERR:                ^~~~~~~~~
```

I'll leave it to you if you prefer this; the alternative I see is to
just rename `IsCorePackage` to `IsImportedCorePackage`, and/or change it
to a helper that takes a `Context` and does the right thing with
`parse_tree` (which, I need for `Destroy`-related reasons and was my
default approach).
2025-12-16 01:33:53 +00:00
Richard Smith 154e4012c4 Include the parent scope when fingerprinting an entity name. (#6473)
This is a prerequisite for support for interop with C++ template names.
No behavior change here, except that it sadly changes the fingerprinting
for a lot of tests.
2025-12-08 15:31:13 +00:00
David BlaikieandDana Jansens a179bd461b Start plumbing through debug info type information with function parameters/return value (#6410)
This adds just enough debug info for i32/int parameters and return
values, with a path forward for adding DWARF type metadata for other
types.

As it happens, return type information is carried separately from
parameter information:
* Return type information is carried in the `type` of the `DISubprogram`
  (as a `DISubroutineType` - which does carry parameter type information
  as well, but that's unused when the DWARF is emitted by LLVM)
* Parameter information is carried by `DILocalVariable`s with a non-zero
  `arg` value (representing the order of function parameters)

In the absence of locations for the parameters (future work), nothing
would usually keep the `DILocalVariable` live/reachable when emitting
DWARF - so for cases where this can happen (for clang, this happens in
optimized builds where all references to the parameter variable might be
optimized away) the variables can be "retained" in a list on the
`DISubprogram` - achieved by passing `AlwaysPreserve` parameter to
`createParameterVariable` (adds them to a list, then that list gets
attached to the `DISubprogram` when it's finalized later)

For now, any unsupported types are emitted as `void*` (except void
return, which is implemented as void) as a placeholder.

Given this example:
```
import Core library "io";
class MyClass {
}
fn Unsupported(v: MyClass) {
}
fn Ret() -> i32 {
  return 42;
}
fn Arg(x: i32) {
  Core.Print(x);
}
fn Run() {
}
```
this is the resulting DWARF:
```
DW_TAG_compile_unit
  DW_AT_name    ("test.carbon")
  DW_TAG_subprogram
    DW_AT_name  ("Unsupported")
    DW_TAG_formal_parameter
      DW_AT_type        (0x00000066 "void *")
  DW_TAG_subprogram
    DW_AT_name  ("Ret")
    DW_AT_type  (0x00000062 "int")
  DW_TAG_subprogram
    DW_AT_name  ("Arg")
    DW_TAG_formal_parameter
      DW_AT_type        (0x00000062 "int")
  DW_TAG_subprogram
    DW_AT_name  ("Run")
  DW_TAG_base_type
    DW_AT_name  ("int")
  DW_TAG_pointer_type
```
And the debugger:
```
(gdb) p Ret()
$1 = 42
(gdb) p Arg(4)
4
$2 = void
```

I'm not sure if there's a way this logic should be merged with the logic
for making the `llvm::Function` type (which the `DISubroutineType`
building code was inspired by/copied from) - since they're done at
different times/places, I don't think there's an easy way to do it in
one pass, but maybe the code can be shared (even if it's run twice) in
some generic `SemIR::Function` type walker.

---------

Co-authored-by: Dana Jansens <danakj@orodu.net>
2025-11-25 23:25:09 +00:00
Jon Ross-Perkins 93a8c5230c Ensure a symbolic final impl has a definition produced (#6236)
Right now, the impl lookup can both fail to resolve the specific
definition because it's symbolic, and return a "final" constant because
it's a `final impl`. This is adding an instruction to help ensure the
specific is resolved.

The constant evaluation is fully recursive, but I'm not adding a TODO
since that's a known issue with impl lookup in general.
2025-11-25 18:59:25 +00:00
Geoff Romer 57a2715f10 Remove support for addr (#6375)
Every test that used `addr` before #6283 should be using `ref` after
this PR. In most cases that was done in #6283, but this PR transitions a
few that I missed in that first pass. In addition, #6283 cloned the old
`addr` tests from `foo.carbon` to `foo_addr.carbon` in order to maintain
test coverage during the transition; this PR removes those cloned tests.
2025-11-18 19:48:58 +00:00
David Blaikie bb9942823f DebugInfo: Emit as "C++" rather than "C" (#6361)
This helps at least lldb handle calling functions (currently the debug
info describes every function as `void()`, so no parameters or return
values are supported) - seems gdb and lldb both depend on demangling to
varying degrees in C code (marking a function as "prototyped" in C in
DWARF does seem to also address this problem).

Given:
```
fn PrintThree() {
  Core.Print(3);
}
```
Before:
```
  (lldb) p PrintThree()
  error: Couldn't look up symbols:
    PrintThree
  Hint: The expression tried to call a function that is not present in
    the target, perhaps because it was optimized out by the compiler.
```
After:
```
  (lldb) p PrintThree()
  3
  (lldb)
```
2025-11-18 18:28:56 +00:00
Dana Jansens 5ae5170421 Allow deduction of tuple and struct literals as symbolic generic facet types (#6365)
Give TupleLiteral and StructLiteral a constant value, if their contents
have constant values. Their constant values are TupleValue and
StructValue respectively. This supports their ability to convert to a
constant type (or facet type).

This way when deduce finds a TupleLiteral as the argument to a
_symbolic_ facet type, it can also find a constant value to use for that
argument. This allows deduction to move onto step two, where it can
substitute into the symbolic parameter from previous deduced arguments,
and then perform the conversion from the TupleValue to the desired facet
type.

Allow `PerformBuiltinConversion()` to convert from a canonical
TupleValue or StructValue to `type` instead of only from literals. Then,
also support conversion from a symbolic binding of type TupleType or
StructType to `type`.
2025-11-13 20:17:44 +00:00
Richard Smith 5db1141f52 Allow adding / removing const with ImplicitAs. (#6323)
If `T` implicitly converts to `U`, then:

 * `const T` implicitly converts to `U`,
 * `T` implicitly converts to `const U`, and
 * `T` implicitly converts to `Optional(U)`.
2025-11-05 07:38:09 +00:00
aa69a484eb Add support for running LLVM optimizer. (#6225)
Adds a flag `--optimize=<mode>` that specifies what to optimize for:

* `--optimize=none` turns off the optimizer as much as possible, but
still respects always_inline.
* `--optimize=debug` aims to be the equivalent of `-Og` / `-O1`, and
provides optimizations that don't affect the ability to debug the
program. This is the default.
* `--optimize=size` optimizes for the size of the produced program, and
aims to be the equivalent of `-Oz`.
* `--optimize=speed` optimizes for the execution time of the produced
program, and aims to be the equivalent of `-O3`.

Following the approach taken by Clang, the optimization level feeds into
both the configuration of the LLVM pass pipeline and the attributes
added to function definitions generated by the frontend.

Optimization is performed in a new phase, `optimize`, which runs between
`lower` and `codegen`.

---------

Co-authored-by: Dana Jansens <danakj@orodu.net>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2025-11-05 00:15:14 +00:00
Geoff Romer 4821eec2f8 Add support for ref patterns (#6283)
Support for `bound`, and for the `ref` tag on arguments, is left as
future work.
2025-10-29 16:28:56 +00:00
Geoff Romer 0811d996e1 Finish renaming BindName and related insts. (#6281)
Resolves the TODO from #6235
2025-10-28 17:17:38 +00:00
Richard Smith 851da43c88 Make Optional support specializing its representation. (#6058)
Switch to using a pair of `MaybeUnformed(T)` and a `bool` as the normal
representation for `Optional(T)`. When `T` is a pointer type, add a
customized representation that uses `MaybeUnformed(T*)`, with a null
representation used for absent values.
2025-10-15 22:34:22 +00:00
Dana Jansens e682a6660d Avoid adding extraneous local instructions while importing witness table entries (#6180)
When deducing arguments for generic parameters of an `impl`, the
deduction calls `Convert` on the input arguments. Often, the input
argument is a facet, and needs to be converted to a type via
FacetAccessType in order to produce a different facet. These
instructions end up being added to the semir, but only their constant
values are needed for the resulting specific returned from Deduce.

In the best case, these extra instructions are just noise in the semir,
or they just cause instruction names to get differentiated with larger
suffixes.

In the worst case, these extra instructions contain references to
instructions from a generic context, and leak them out of that generic
context and into another. In particular, when importing a
LookupImplWitness instruction, the re-evaluation of it can do deduce
(when the lookup is against a generic `impl`). The instructions created
in Deduce are not part of the import, and end up referring to imported
instructions from the local context, which leads to confusion in the
toolchain, and can crash.

The `import_self_specific.carbon` test demonstrates this. It causes the
`I.F` function to be imported from the `I` interface when building the
witness table for the `impl`. Doing so imports the specific of `C` which
includes a LookupImplWitness for `Self.Accoc` in `I`. The `Self` is a
BindSymbolicName with generic binding index 0, in `I`. When Convert
creates instructions in the generic `impl forall D`, however, they end
up referencing and including this BindSymbolicName into its eval block.
But the generic binding 0 in the `impl` is a very different thing (a
value of type `E`). This confusion leads to crashes.
2025-10-09 16:07:30 +00:00