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.
When an initializing expression is used to initialize a var parameter,
we need to create the storage earlier in SemIR than the initializing
expression. To do so, pass a pending block to initialization containing
the var storage.
Also stop using `temporary` for this purpose, since we treat temporaries
as potentially-constant and immutable, but `var` parameters can be
mutated by the callee. We should ideally introduce a new kind of
instruction for this purpose but for now we just use `var_storage`.
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>
This includes checking and lowering for concrete form literals. Support
for symbolic forms is future work.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
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
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>
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)
```
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>
This changes `Destroy` to use an interface for its implementation.
Note that this change includes a lot of test updates. Even when
`Destroy` is a no-op, it still causes code generation as part of
determining that.
Originally I was trying to use ranges to cut down the scope of this, and
to a degree I think they have. But a flipside here is that cases where
no destructors should be generated -- particularly globals -- would be
needed to completely remove destructor calls. Even for ranges, the range
can often include the destructor placement. So I've shifted
frame-of-thought a little: accept a bunch of destructor churn, because
destructors are needed and will be prevalent. The verbosity is a feature
of the design to make desugaring apparent in IR, not a bug.
Previously we created allocas for temporaries at whatever point in the
output LLVM function we'd reached. This would result in these being
dynamic allocas (performing a dynamic stack allocation), which is
inefficent and can lead to a stack overflow if it happens in a loop.
Switch to putting the allocas in the entry block instead, and instead
generate a lifetime start marker when we reach the point where the
temporary is introduced. We already did this for local variables; this
is just factoring out and reusing that code.
Adds min-preludes to a few more slowest tests, and adds them to most of
the lowering tests, with a few exceptions that make use of operators.
This take the runtime of file_test down from about 8s to about 7s on my
machine.
We add support for Negate on uints in the min-preludes.
This drops the wall clock time for running file_test from 10s to 8s on
my machine. There's many more tests to convert, as each one takes the
test from ~1s to ~100ms. Compiling the full prelude is a bit slow now
since #5653, and before that file_test was taking about 3.5s.
We introduce a few more flavours of min_prelude to support more tests.
- The actual reason I started this: minor lowering updates in the golden
LLVM IR
- Process.inc changed enough to need a patch context update.
- https://github.com/llvm/llvm-project/pull/123126 added `proto_library`
uses without a `load`, which is broken in bazel 8
- Just commenting these out because we don't use them. I'll follow up
separately about a possible fix, but continuing to use `WORKSPACE` is a
bigger issue LLVM probably should address.
- Note this update is also triggering removal of `migrate_cpp`, in #4887
Include the index rather than the name in the fingerprint of a symbolic
binding. While both the index and the name contribute to the canonical
identity, using either one of them in the fingerprint is sufficient to
ensure that distinct entities get different fingerprints. Changing the
name of a symbolic binding should ideally not result in fingerprint
changes, so exclude the name from the fingerprint when we have an index.
Use the canonical type and constraint when fingerprinting an impl, so
that uses of names in `name_ref` instructions aren't considered, only
the entity the name resolves to, and different ways of spelling the same
type have the same fingerprint. This similarly allows compatible changes
to be made to impls without changing the fingerprint.
Exclude the declaration block when determining the fingerprint of a
declaration. The declaration block contains the declarations of
parameters of the declaration, which do affect whether two declarations
are identical, but not whether they denote the same entity, because it
would be invalid to have different declaration blocks for declarations
with the same name in the same scope. Therefore changes to the
declaration block are compatible, and it's useful for such changes to
not affect the fingerprint.
This is not easy to test in isolation with our current testing
machinery. However, a follow-on PR will change the name of a parameter
in the prelude, and with this in place, will not cause any changes to
occur elsewhere in the toolchain tests.
Use it in the instruction namer to make instruction names more stable
across unrelated changes to the toolchain or the prelude.
---------
Co-authored-by: Dana Jansens <danakj@orodu.net>
Non-entry-block allocas will allocate new stack memory each time they're
reached, resulting in leaking stack memory over time for allocas in a
loop. Move all such allocas to the entry block instead, and use an LLVM
intrinsic to mark when the lifetime of the variable actually begins.
Goal is to reduce churn in names in test updates (by churning a lot of
them in this PR).
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
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>
When an `IntLiteral` appears as an operand of an `if` expression,
convert it to `i32` for now, so that we don't reject things like `if
cond then 1 else 2` due to having a non-constant value of type
`IntLiteral`.
For tuple indexing expressions such as `(a, b).0`, convert the index to
type `IntLiteral`, not to type `i32`. This isn't strictly necessary to
do in this PR, but avoids the need to provide an `IntLiteral` -> `i32`
implicit conversion for `no_prelude` tests using this syntax.
Also propagate the pattern IR along with the pattern-match IR, and use
it where appropriate.
Strictly speaking, some parts of the pattern-match IR are allocated
eagerly, while traversing the pattern's parse tree, but they still
aren't actually emitted until we traverse the associated pattern insts.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.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>
There's not much mangling happening yet - but Run -> main (and some
overloading numbering happening, maybe LLVM is doing that 'helpfully'
under the hood?) is enough to demonstrate this improvement/fix.
Ah, here it is:
```
#0 llvm::ValueSymbolTable::makeUniqueName (this=0x50287fe5b6c0, V=0x50287fe827e8, UniqueName="F") at external/_main~llvm_project~llvm-project/llvm/lib/IR/ValueSymbolTable.cpp:45
#1 0x000055555c40f964 in llvm::ValueSymbolTable::reinsertValue (this=0x50287fe5b6c0, V=0x50287fe827e8) at external/_main~llvm_project~llvm-project/llvm/lib/IR/ValueSymbolTable.cpp:100
#2 0x000055555c2a91df in llvm::SymbolTableListTraits<llvm::Function>::addNodeToList (this=0x50287fd16f18, V=0x50287fe827e8) at external/_main~llvm_project~llvm-project/llvm/lib/IR/SymbolTableListTraitsImpl.h:75
#3 0x000055555c2a90e5 in llvm::iplist_impl<llvm::simple_ilist<llvm::Function>, llvm::SymbolTableListTraits<llvm::Function> >::insert (this=0x50287fd16f18, where=..., New=0x50287fe827e8)
at external/_main~llvm_project~llvm-project/llvm/include/llvm/ADT/ilist.h:166
#4 0x000055555c27fef2 in llvm::iplist_impl<llvm::simple_ilist<llvm::Function>, llvm::SymbolTableListTraits<llvm::Function> >::push_back (this=0x50287fd16f18, val=0x50287fe827e8) at external/_main~llvm_project~llvm-project/llvm/include/llvm/ADT/ilist.h:250
#5 0x000055555c27faeb in llvm::Function::Function (this=0x50287fe827e8, Ty=0x50287fd43058, Linkage=llvm::GlobalValue::ExternalLinkage, AddrSpace=0, name="F", ParentModule=0x50287fd16f00) at external/_main~llvm_project~llvm-project/llvm/lib/IR/Function.cpp:521
#6 0x0000555559441f95 in llvm::Function::Create (Ty=0x50287fd43058, Linkage=llvm::GlobalValue::ExternalLinkage, AddrSpace=0, N="F", M=0x50287fd16f00) at external/_main~llvm_project~llvm-project/llvm/include/llvm/IR/Function.h:175
#7 0x000055555c27ebac in llvm::Function::Create (Ty=0x50287fd43058, Linkage=llvm::GlobalValue::ExternalLinkage, N="F", M=...) at external/_main~llvm_project~llvm-project/llvm/lib/IR/Function.cpp:398
#8 0x0000555558ce7bb5 in Carbon::Lower::FileContext::BuildFunctionDecl (this=0x7fffffffc438, function_id=...) at toolchain/lower/file_context.cpp:257
```
That's where LLVM decides to make a new name (name.number) when asked to
create a new global with the same name as an existing global.
It's not a valid mangling scheme - since the name won't be stable
between different compilations, but it is enough to make
single-compilation code build/run for now.
Seems to work with lldb ( https://pastebin.com/igKkNECm ), though gdb
has /some/ trouble with the paths (they aren't complete - just using the
filename directly, not providing the working directory - might be some
quick hacks that can help there).
Refactors a bunch of the SemIRDiagnosticConverter to be able to use that
from Lower to access source locations there to use in debug info.
I assume some of this is a bit jank/would need to be fixed/improved in
the future - like the context functor that's passed into ConvertLoc?
(not totally clear what that's for/what the debug info will be missing
out on in its absence, I could throw a FIXME in there if you like)
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Still doesn't have line tables, so of limited value (at least now
this'll be enough that LLVM really generates debug info into the
resulting object file (whereas with only the compilation unit metadata,
LLVM will consider it empty and avoid emitting any of it)) - but another
step along the path.
This also doesn't attach the right source location to the functions -
I'll do that in a follow-up change because I think it'll require the
majority of the refactoring between driver and check to extract the
essential functionality sem_ir_diagnostic_converter, I think, to allow
retrieving source locations during lowering.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
This adds just the debug info metadata for Compilation Units (the top
level container of debug info) - but without anything in them, LLVM
won't emit them at all, so while this is testable at the IR level, it
isn't observable at the object level until more debug info is added.
A couple of starting points in this patch:
* A flag (`--debug-info`, seems to match the naming/style of other flags
in the carbon driver, though this is different from the naming
conventions of clang/gcc) that enables debug info when lowering. Open to
other names/approaches (on by default? historically debug info's been to
large/expensive to do this, so sticking with that precedent for now).
* Enabling that flag by default in the lowering tests - I do find the
churn on golden tests a bit rough, and adding more features to all the
tests means more churn, but it seems consistent with the approach so far
- keep an eye on this and perhaps revisit this if the churn gets too
annoying
---------
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Don't format the *type of* the function `F` as `"F"`. Instead use
`"<type of F>"`.
Also improve instruction naming for function and generic class name
values: name the value after the function or generic class, and add a
`.type` suffix to the type.
This has is a nice-to-have for me. Frequently I want to run a specific
test, and end up digging through output to be able to copy-paste the run
line. This uses TIP lines to inject the command into the file when using
AUTOUPDATE.
Note, one of the reasons I want this is because "bazel test
//toolchain/testing:file_test --test_output=all" has been regularly
exceeding bazel's output limit for me (workaround is either opening the
output file or specifying an obscure output limit flag), making it a
little harder for me to get the commands. However, frequently I'm adding
a file and want to iterate on it, so that's really the use case I have
in mind here.
Modifies the core package and literal handling to use factory functions
for standard type literals.
Updates function/builtin/import.carbon to stop depending on the prelude,
since it would list all the impls in the core file. Updates
alias/builtins.carbon to be failing (the type values cannot be aliased).
This removes the builtin FunctionType, replacing it with a FunctionType
instruction. The constant for a FunctionDecl is now a StructValue with
type of FunctionType.
Note this means a function declaration produces _both_ a type, and a
value of the type. This has some consequences in terms of circularity,
and makes the importing of function declarations a little more complex.
It'll get particularly peculiar for imports because of the behavior of
the reference, but that's a known issue due to other things such as
`alias`. The impact will hopefully be contained to
ResolvePrevInstForMerge (and ImportRefs).
To note a small formatting change in diagnostics:
```
- // CHECK:STDERR: fail_member_lookup.carbon:[[@LINE+4]]:3: ERROR: Value of type `<associated <function> in Interface>` is not callable.
+ // CHECK:STDERR: fail_member_lookup.carbon:[[@LINE+4]]:3: ERROR: Value of type `<associated F in Interface>` is not callable.
- // CHECK:STDERR: fail_todo_facet_lookup.carbon:[[@LINE+4]]:3: ERROR: Value of type `<associated <function> in Interface>` is not callable.
+ // CHECK:STDERR: fail_todo_facet_lookup.carbon:[[@LINE+4]]:3: ERROR: Value of type `<associated F in Interface>` is not callable.
```
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Change the names for emitted globals for constants with storage to
include both the name of the constant and the name of the use.
This causes the instructions to also be named in SemIR and in LLVM IR
constants.
Make constant emission non-recursive, and stop building a bogus
FunctionContext to emit constants.
To support this, move `InstConstantKind` from the typed instruction
definition into the `.def` file, and add more macros to allow us to
generate case labels based on whether an instruction is a constant.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
First steps towards using constant values in lowering.
For now, we reuse the regular instruction lowering to lower constants.
This mostly works, because we don't actually need an `llvm::Function` or
a current basic block when lowering a constant most of the time.
However, a special case is needed for lowering aggregate value constants
because they would otherwise create a stack alloca to store the
constant. Separate constant lowering code will be added in a future
change to clean this up.
When lowering a constant initializing expression, the result is a value
of the destination type, rather than code to initialize the destination,
so a separate copy step is required when finishing initialization from a
constant for a type that uses in-place initialization. Handling this
required extending `ReturnExpr` to track its destination location.
We currently often create non-constant `*_access` SemIR instructions
that are only used by constant `*_init` instructions. These cause
lowering to leave behind `getelementptr` instructions in the lowered IR
that are now unused. It should be possible to detect this case and avoid
producing these instructions, or to produce them lazily, but for now
we're just leaving them around for LLVM to clean up.
Factor out `SemIR::InstNamer` and also use it when lowering to LLVM IR.
Automatically name all instructions created with our `IRBuilder` based
on the name computed by the `InstNamer`, and likewise name basic blocks
using the label generated by the `InstNamer`.
Move some of the existing naming logic out from lower into `InstNamer`
so that it's also used in SemIR. In particular, we now name call
instructions after their callee, or after the builtin name for calls to
builtins.
Computing and adding these names isn't completely free. This instruction
naming is designed to be optional, so that we can turn it off for builds
where the LLVM IR will only be converted to assembly and won't be seen
by a human, but so far it's enabled unconditionally. We can tune that
later as needed.
Trust semantics to have put them in the right places.
Many parts of lowering still need to be updated to use the value
representation chosen at the semantics layer, but this is an incremental
step towards that.
Richard Smith
Jon Ross-Perkinsandjonmeow
Nicholas Bishop
Geoff RomerandJon Ross-Perkins
Burak Emir
David BlaikieandDana Jansens
josh11bandJosh L
Brymer Meneses
