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13434f0e8a64d5fa8decd6685be6c1a9649e92af
carbon-lang/toolchain/check/eval.cpp
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Geoff RomerandRichard Smith 13434f0e8a Model var as a pattern operator (#4720) 
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2025-01-17 17:51:34 +00:00

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// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "toolchain/check/eval.h"
#include "toolchain/base/kind_switch.h"
#include "toolchain/check/diagnostic_helpers.h"
#include "toolchain/check/generic.h"
#include "toolchain/check/import_ref.h"
#include "toolchain/diagnostics/diagnostic_emitter.h"
#include "toolchain/diagnostics/format_providers.h"
#include "toolchain/sem_ir/builtin_function_kind.h"
#include "toolchain/sem_ir/function.h"
#include "toolchain/sem_ir/generic.h"
#include "toolchain/sem_ir/ids.h"
#include "toolchain/sem_ir/inst_kind.h"
#include "toolchain/sem_ir/typed_insts.h"
namespace Carbon::Check {
namespace {
// Information about an eval block of a specific that we are currently building.
struct SpecificEvalInfo {
// The region within the specific whose eval block we are building.
SemIR::GenericInstIndex::Region region;
// The work-in-progress contents of the eval block.
llvm::ArrayRef<SemIR::InstId> values;
};
// Information about the context within which we are performing evaluation.
class EvalContext {
public:
explicit EvalContext(
Context& context, SemIRLoc fallback_loc,
SemIR::SpecificId specific_id = SemIR::SpecificId::Invalid,
std::optional<SpecificEvalInfo> specific_eval_info = std::nullopt)
: context_(context),
fallback_loc_(fallback_loc),
specific_id_(specific_id),
specific_eval_info_(specific_eval_info) {}
// Gets the location to use for diagnostics if a better location is
// unavailable.
// TODO: This is also sometimes unavailable.
auto fallback_loc() const -> SemIRLoc { return fallback_loc_; }
// Returns a location to use to point at an instruction in a diagnostic, given
// a list of instructions that might have an attached location. This is the
// location of the first instruction in the list that has a location if there
// is one, and otherwise the fallback location.
auto GetDiagnosticLoc(llvm::ArrayRef<SemIR::InstId> inst_ids) -> SemIRLoc {
for (auto inst_id : inst_ids) {
if (inst_id.is_valid() && context_.insts().GetLocId(inst_id).is_valid()) {
return inst_id;
}
}
return fallback_loc_;
}
// Gets the value of the specified compile-time binding in this context.
// Returns `Invalid` if the value is not fixed in this context.
auto GetCompileTimeBindValue(SemIR::CompileTimeBindIndex bind_index)
-> SemIR::ConstantId {
if (!bind_index.is_valid() || !specific_id_.is_valid()) {
return SemIR::ConstantId::Invalid;
}
const auto& specific = specifics().Get(specific_id_);
auto args = inst_blocks().Get(specific.args_id);
// Bindings past the ones with known arguments can appear as local
// bindings of entities declared within this generic.
if (static_cast<size_t>(bind_index.index) >= args.size()) {
return SemIR::ConstantId::Invalid;
}
return constant_values().Get(args[bind_index.index]);
}
// Given a constant value from the SemIR we're evaluating, finds the
// corresponding constant value to use in the context of this evaluation.
// This can be different if the original SemIR is for a generic and we are
// evaluating with specific arguments for the generic parameters.
auto GetInContext(SemIR::ConstantId const_id) -> SemIR::ConstantId {
if (!const_id.is_symbolic()) {
return const_id;
}
// While resolving a specific, map from previous instructions in the eval
// block into their evaluated values. These values won't be present on the
// specific itself yet, so `GetConstantInSpecific` won't be able to find
// them.
if (specific_eval_info_) {
const auto& symbolic_info =
constant_values().GetSymbolicConstant(const_id);
if (symbolic_info.index.is_valid() &&
symbolic_info.generic_id ==
specifics().Get(specific_id_).generic_id &&
symbolic_info.index.region() == specific_eval_info_->region) {
auto inst_id = specific_eval_info_->values[symbolic_info.index.index()];
CARBON_CHECK(inst_id.is_valid(),
"Forward reference in eval block: index {0} referenced "
"before evaluation",
symbolic_info.index.index());
return constant_values().Get(inst_id);
}
}
// Map from a specific constant value to the canonical value.
return GetConstantInSpecific(sem_ir(), specific_id_, const_id);
}
// Gets the constant value of the specified instruction in this context.
auto GetConstantValue(SemIR::InstId inst_id) -> SemIR::ConstantId {
return GetInContext(constant_values().Get(inst_id));
}
// Gets the constant value of the specified type in this context.
auto GetConstantValue(SemIR::TypeId type_id) -> SemIR::ConstantId {
return GetInContext(types().GetConstantId(type_id));
}
// Gets the constant value of the specified type in this context.
auto GetConstantValueAsType(SemIR::TypeId id) -> SemIR::TypeId {
return context().GetTypeIdForTypeConstant(GetConstantValue(id));
}
// Gets the instruction describing the constant value of the specified type in
// this context.
auto GetConstantValueAsInst(SemIR::TypeId id) -> SemIR::Inst {
return insts().Get(
context().constant_values().GetInstId(GetConstantValue(id)));
}
auto ints() -> SharedValueStores::IntStore& { return sem_ir().ints(); }
auto floats() -> SharedValueStores::FloatStore& { return sem_ir().floats(); }
auto entity_names() -> SemIR::EntityNameStore& {
return sem_ir().entity_names();
}
auto functions() -> const ValueStore<SemIR::FunctionId>& {
return sem_ir().functions();
}
auto classes() -> const ValueStore<SemIR::ClassId>& {
return sem_ir().classes();
}
auto interfaces() -> const ValueStore<SemIR::InterfaceId>& {
return sem_ir().interfaces();
}
auto facet_types() -> CanonicalValueStore<SemIR::FacetTypeId>& {
return sem_ir().facet_types();
}
auto specifics() -> const SemIR::SpecificStore& {
return sem_ir().specifics();
}
auto type_blocks() -> SemIR::BlockValueStore<SemIR::TypeBlockId>& {
return sem_ir().type_blocks();
}
auto insts() -> const SemIR::InstStore& { return sem_ir().insts(); }
auto inst_blocks() -> SemIR::InstBlockStore& {
return sem_ir().inst_blocks();
}
// Gets the constant value store. Note that this does not provide the constant
// values that should be used from this evaluation context, and so should be
// used with caution.
auto constant_values() -> const SemIR::ConstantValueStore& {
return sem_ir().constant_values();
}
// Gets the types store. Note that this does not provide the type values that
// should be used from this evaluation context, and so should be used with
// caution.
auto types() -> const SemIR::TypeStore& { return sem_ir().types(); }
auto context() -> Context& { return context_; }
auto sem_ir() -> SemIR::File& { return context().sem_ir(); }
auto emitter() -> Context::DiagnosticEmitter& { return context().emitter(); }
private:
// The type-checking context in which we're performing evaluation.
Context& context_;
// The location to use for diagnostics when a better location isn't available.
SemIRLoc fallback_loc_;
// The specific that we are evaluating within.
SemIR::SpecificId specific_id_;
// If we are currently evaluating an eval block for `specific_id_`,
// information about that evaluation.
std::optional<SpecificEvalInfo> specific_eval_info_;
};
} // namespace
namespace {
// The evaluation phase for an expression, computed by evaluation. These are
// ordered so that the phase of an expression is the numerically highest phase
// of its constituent evaluations. Note that an expression with any runtime
// component is known to have Runtime phase even if it involves an evaluation
// with UnknownDueToError phase.
enum class Phase : uint8_t {
// Value could be entirely and concretely computed.
Template,
// Evaluation phase is symbolic because the expression involves specifically a
// reference to `.Self`.
PeriodSelfSymbolic,
// Evaluation phase is symbolic because the expression involves a reference to
// a symbolic binding.
Symbolic,
// The evaluation phase is unknown because evaluation encountered an
// already-diagnosed semantic or syntax error. This is treated as being
// potentially constant, but with an unknown phase.
UnknownDueToError,
// The expression has runtime phase because of a non-constant subexpression.
Runtime,
};
} // namespace
// Gets the phase in which the value of a constant will become available.
static auto GetPhase(EvalContext& eval_context, SemIR::ConstantId constant_id)
-> Phase {
if (!constant_id.is_constant()) {
return Phase::Runtime;
} else if (constant_id == SemIR::ErrorInst::SingletonConstantId) {
return Phase::UnknownDueToError;
} else if (constant_id.is_template()) {
return Phase::Template;
} else if (eval_context.constant_values().DependsOnGenericParameter(
constant_id)) {
return Phase::Symbolic;
} else {
CARBON_CHECK(constant_id.is_symbolic());
return Phase::PeriodSelfSymbolic;
}
}
// Returns the later of two phases.
static auto LatestPhase(Phase a, Phase b) -> Phase {
return static_cast<Phase>(
std::max(static_cast<uint8_t>(a), static_cast<uint8_t>(b)));
}
// `where` expressions using `.Self` should not be considered symbolic
// - `Interface where .Self impls I and .A = bool` -> template
// - `T:! type` ... `Interface where .A = T` -> symbolic, since uses `T` which
// is symbolic and not due to `.Self`.
static auto UpdatePhaseIgnorePeriodSelf(EvalContext& eval_context,
SemIR::ConstantId constant_id,
Phase* phase) {
Phase constant_phase = GetPhase(eval_context, constant_id);
// Since LatestPhase(x, Phase::Template) == x, this is equivalent to replacing
// Phase::PeriodSelfSymbolic with Phase::Template.
if (constant_phase != Phase::PeriodSelfSymbolic) {
*phase = LatestPhase(*phase, constant_phase);
}
}
// Forms a `constant_id` describing a given evaluation result.
static auto MakeConstantResult(Context& context, SemIR::Inst inst, Phase phase)
-> SemIR::ConstantId {
switch (phase) {
case Phase::Template:
return context.constants().GetOrAdd(inst,
SemIR::ConstantStore::IsTemplate);
case Phase::PeriodSelfSymbolic:
return context.constants().GetOrAdd(
inst, SemIR::ConstantStore::IsPeriodSelfSymbolic);
case Phase::Symbolic:
return context.constants().GetOrAdd(inst,
SemIR::ConstantStore::IsSymbolic);
case Phase::UnknownDueToError:
return SemIR::ErrorInst::SingletonConstantId;
case Phase::Runtime:
return SemIR::ConstantId::NotConstant;
}
}
// Forms a `constant_id` describing why an evaluation was not constant.
static auto MakeNonConstantResult(Phase phase) -> SemIR::ConstantId {
return phase == Phase::UnknownDueToError
? SemIR::ErrorInst::SingletonConstantId
: SemIR::ConstantId::NotConstant;
}
// Converts a bool value into a ConstantId.
static auto MakeBoolResult(Context& context, SemIR::TypeId bool_type_id,
bool result) -> SemIR::ConstantId {
return MakeConstantResult(
context,
SemIR::BoolLiteral{.type_id = bool_type_id,
.value = SemIR::BoolValue::From(result)},
Phase::Template);
}
// Converts an APInt value into a ConstantId.
static auto MakeIntResult(Context& context, SemIR::TypeId type_id,
bool is_signed, llvm::APInt value)
-> SemIR::ConstantId {
CARBON_CHECK(is_signed == context.types().IsSignedInt(type_id));
auto result = is_signed ? context.ints().AddSigned(std::move(value))
: context.ints().AddUnsigned(std::move(value));
return MakeConstantResult(
context, SemIR::IntValue{.type_id = type_id, .int_id = result},
Phase::Template);
}
// Converts an APFloat value into a ConstantId.
static auto MakeFloatResult(Context& context, SemIR::TypeId type_id,
llvm::APFloat value) -> SemIR::ConstantId {
auto result = context.floats().Add(std::move(value));
return MakeConstantResult(
context, SemIR::FloatLiteral{.type_id = type_id, .float_id = result},
Phase::Template);
}
// `GetConstantValue` checks to see whether the provided ID describes a value
// with constant phase, and if so, returns the corresponding constant value.
// Overloads are provided for different kinds of ID.
// If the given instruction is constant, returns its constant value.
static auto GetConstantValue(EvalContext& eval_context, SemIR::InstId inst_id,
Phase* phase) -> SemIR::InstId {
auto const_id = eval_context.GetConstantValue(inst_id);
*phase = LatestPhase(*phase, GetPhase(eval_context, const_id));
return eval_context.constant_values().GetInstId(const_id);
}
// Given a type which may refer to a generic parameter, returns the
// corresponding type in the evaluation context.
static auto GetConstantValue(EvalContext& eval_context, SemIR::TypeId type_id,
Phase* phase) -> SemIR::TypeId {
auto const_id = eval_context.GetConstantValue(type_id);
*phase = LatestPhase(*phase, GetPhase(eval_context, const_id));
return eval_context.context().GetTypeIdForTypeConstant(const_id);
}
// If the given instruction block contains only constants, returns a
// corresponding block of those values.
static auto GetConstantValue(EvalContext& eval_context,
SemIR::InstBlockId inst_block_id, Phase* phase)
-> SemIR::InstBlockId {
if (!inst_block_id.is_valid()) {
return SemIR::InstBlockId::Invalid;
}
auto insts = eval_context.inst_blocks().Get(inst_block_id);
llvm::SmallVector<SemIR::InstId> const_insts;
for (auto inst_id : insts) {
auto const_inst_id = GetConstantValue(eval_context, inst_id, phase);
if (!const_inst_id.is_valid()) {
return SemIR::InstBlockId::Invalid;
}
// Once we leave the small buffer, we know the first few elements are all
// constant, so it's likely that the entire block is constant. Resize to the
// target size given that we're going to allocate memory now anyway.
if (const_insts.size() == const_insts.capacity()) {
const_insts.reserve(insts.size());
}
const_insts.push_back(const_inst_id);
}
// TODO: If the new block is identical to the original block, and we know the
// old ID was canonical, return the original ID.
return eval_context.inst_blocks().AddCanonical(const_insts);
}
// Compute the constant value of a type block. This may be different from the
// input type block if we have known generic arguments.
static auto GetConstantValue(EvalContext& eval_context,
SemIR::StructTypeFieldsId fields_id, Phase* phase)
-> SemIR::StructTypeFieldsId {
if (!fields_id.is_valid()) {
return SemIR::StructTypeFieldsId::Invalid;
}
auto fields = eval_context.context().struct_type_fields().Get(fields_id);
llvm::SmallVector<SemIR::StructTypeField> new_fields;
for (auto field : fields) {
auto new_type_id = GetConstantValue(eval_context, field.type_id, phase);
if (!new_type_id.is_valid()) {
return SemIR::StructTypeFieldsId::Invalid;
}
// Once we leave the small buffer, we know the first few elements are all
// constant, so it's likely that the entire block is constant. Resize to the
// target size given that we're going to allocate memory now anyway.
if (new_fields.size() == new_fields.capacity()) {
new_fields.reserve(fields.size());
}
new_fields.push_back({.name_id = field.name_id, .type_id = new_type_id});
}
// TODO: If the new block is identical to the original block, and we know the
// old ID was canonical, return the original ID.
return eval_context.context().struct_type_fields().AddCanonical(new_fields);
}
// Compute the constant value of a type block. This may be different from the
// input type block if we have known generic arguments.
static auto GetConstantValue(EvalContext& eval_context,
SemIR::TypeBlockId type_block_id, Phase* phase)
-> SemIR::TypeBlockId {
if (!type_block_id.is_valid()) {
return SemIR::TypeBlockId::Invalid;
}
auto types = eval_context.type_blocks().Get(type_block_id);
llvm::SmallVector<SemIR::TypeId> new_types;
for (auto type_id : types) {
auto new_type_id = GetConstantValue(eval_context, type_id, phase);
if (!new_type_id.is_valid()) {
return SemIR::TypeBlockId::Invalid;
}
// Once we leave the small buffer, we know the first few elements are all
// constant, so it's likely that the entire block is constant. Resize to the
// target size given that we're going to allocate memory now anyway.
if (new_types.size() == new_types.capacity()) {
new_types.reserve(types.size());
}
new_types.push_back(new_type_id);
}
// TODO: If the new block is identical to the original block, and we know the
// old ID was canonical, return the original ID.
return eval_context.type_blocks().AddCanonical(new_types);
}
// The constant value of a specific is the specific with the corresponding
// constant values for its arguments.
static auto GetConstantValue(EvalContext& eval_context,
SemIR::SpecificId specific_id, Phase* phase)
-> SemIR::SpecificId {
if (!specific_id.is_valid()) {
return SemIR::SpecificId::Invalid;
}
const auto& specific = eval_context.specifics().Get(specific_id);
auto args_id = GetConstantValue(eval_context, specific.args_id, phase);
if (!args_id.is_valid()) {
return SemIR::SpecificId::Invalid;
}
if (args_id == specific.args_id) {
return specific_id;
}
return MakeSpecific(eval_context.context(), eval_context.fallback_loc(),
specific.generic_id, args_id);
}
// Like `GetConstantValue` but does a `FacetTypeId` -> `FacetTypeInfo`
// conversion. Does not perform canonicalization.
static auto GetConstantFacetTypeInfo(EvalContext& eval_context,
SemIR::FacetTypeId facet_type_id,
Phase* phase) -> SemIR::FacetTypeInfo {
SemIR::FacetTypeInfo info = eval_context.facet_types().Get(facet_type_id);
for (auto& interface : info.impls_constraints) {
interface.specific_id =
GetConstantValue(eval_context, interface.specific_id, phase);
}
for (auto& rewrite : info.rewrite_constraints) {
rewrite.lhs_const_id = eval_context.GetInContext(rewrite.lhs_const_id);
rewrite.rhs_const_id = eval_context.GetInContext(rewrite.rhs_const_id);
// `where` requirements using `.Self` should not be considered symbolic
UpdatePhaseIgnorePeriodSelf(eval_context, rewrite.lhs_const_id, phase);
UpdatePhaseIgnorePeriodSelf(eval_context, rewrite.rhs_const_id, phase);
}
// TODO: Process other requirements.
return info;
}
// Replaces the specified field of the given typed instruction with its constant
// value, if it has constant phase. Returns true on success, false if the value
// has runtime phase.
template <typename InstT, typename FieldIdT>
static auto ReplaceFieldWithConstantValue(EvalContext& eval_context,
InstT* inst, FieldIdT InstT::*field,
Phase* phase) -> bool {
auto unwrapped = GetConstantValue(eval_context, inst->*field, phase);
if (!unwrapped.is_valid() && (inst->*field).is_valid()) {
return false;
}
inst->*field = unwrapped;
return true;
}
// If the specified fields of the given typed instruction have constant values,
// replaces the fields with their constant values and builds a corresponding
// constant value. Otherwise returns `ConstantId::NotConstant`. Returns
// `ErrorInst::SingletonConstantId` if any subexpression is an error.
//
// The constant value is then checked by calling `validate_fn(typed_inst)`,
// which should return a `bool` indicating whether the new constant is valid. If
// validation passes, `transform_fn(typed_inst)` is called to produce the final
// constant instruction, and a corresponding ConstantId for the new constant is
// returned. If validation fails, it should produce a suitable error message.
// `ErrorInst::SingletonConstantId` is returned.
template <typename InstT, typename ValidateFn, typename TransformFn,
typename... EachFieldIdT>
static auto RebuildIfFieldsAreConstantImpl(
EvalContext& eval_context, SemIR::Inst inst, ValidateFn validate_fn,
TransformFn transform_fn, EachFieldIdT InstT::*... each_field_id)
-> SemIR::ConstantId {
// Build a constant instruction by replacing each non-constant operand with
// its constant value.
auto typed_inst = inst.As<InstT>();
Phase phase = Phase::Template;
if ((ReplaceFieldWithConstantValue(eval_context, &typed_inst, each_field_id,
&phase) &&
...)) {
if (phase == Phase::UnknownDueToError || !validate_fn(typed_inst)) {
return SemIR::ErrorInst::SingletonConstantId;
}
return MakeConstantResult(eval_context.context(), transform_fn(typed_inst),
phase);
}
return MakeNonConstantResult(phase);
}
// Same as above but with an identity transform function.
template <typename InstT, typename ValidateFn, typename... EachFieldIdT>
static auto RebuildAndValidateIfFieldsAreConstant(
EvalContext& eval_context, SemIR::Inst inst, ValidateFn validate_fn,
EachFieldIdT InstT::*... each_field_id) -> SemIR::ConstantId {
return RebuildIfFieldsAreConstantImpl(eval_context, inst, validate_fn,
std::identity{}, each_field_id...);
}
// Same as above but with no validation step.
template <typename InstT, typename TransformFn, typename... EachFieldIdT>
static auto TransformIfFieldsAreConstant(EvalContext& eval_context,
SemIR::Inst inst,
TransformFn transform_fn,
EachFieldIdT InstT::*... each_field_id)
-> SemIR::ConstantId {
return RebuildIfFieldsAreConstantImpl(
eval_context, inst, [](...) { return true; }, transform_fn,
each_field_id...);
}
// Same as above but with no validation or transform step.
template <typename InstT, typename... EachFieldIdT>
static auto RebuildIfFieldsAreConstant(EvalContext& eval_context,
SemIR::Inst inst,
EachFieldIdT InstT::*... each_field_id)
-> SemIR::ConstantId {
return RebuildIfFieldsAreConstantImpl(
eval_context, inst, [](...) { return true; }, std::identity{},
each_field_id...);
}
// Rebuilds the given aggregate initialization instruction as a corresponding
// constant aggregate value, if its elements are all constants.
static auto RebuildInitAsValue(EvalContext& eval_context, SemIR::Inst inst,
SemIR::InstKind value_kind)
-> SemIR::ConstantId {
return TransformIfFieldsAreConstant(
eval_context, inst,
[&](SemIR::AnyAggregateInit result) {
return SemIR::AnyAggregateValue{.kind = value_kind,
.type_id = result.type_id,
.elements_id = result.elements_id};
},
&SemIR::AnyAggregateInit::type_id, &SemIR::AnyAggregateInit::elements_id);
}
// Performs an access into an aggregate, retrieving the specified element.
static auto PerformAggregateAccess(EvalContext& eval_context, SemIR::Inst inst)
-> SemIR::ConstantId {
auto access_inst = inst.As<SemIR::AnyAggregateAccess>();
Phase phase = Phase::Template;
if (ReplaceFieldWithConstantValue(eval_context, &access_inst,
&SemIR::AnyAggregateAccess::aggregate_id,
&phase)) {
if (auto aggregate =
eval_context.insts().TryGetAs<SemIR::AnyAggregateValue>(
access_inst.aggregate_id)) {
auto elements = eval_context.inst_blocks().Get(aggregate->elements_id);
auto index = static_cast<size_t>(access_inst.index.index);
CARBON_CHECK(index < elements.size(), "Access out of bounds.");
// `Phase` is not used here. If this element is a template constant, then
// so is the result of indexing, even if the aggregate also contains a
// symbolic context.
return eval_context.GetConstantValue(elements[index]);
} else {
CARBON_CHECK(phase != Phase::Template,
"Failed to evaluate template constant {0} arg0: {1}", inst,
eval_context.insts().Get(access_inst.aggregate_id));
}
return MakeConstantResult(eval_context.context(), access_inst, phase);
}
return MakeNonConstantResult(phase);
}
// Performs an index into a homogeneous aggregate, retrieving the specified
// element.
static auto PerformArrayIndex(EvalContext& eval_context, SemIR::ArrayIndex inst)
-> SemIR::ConstantId {
Phase phase = Phase::Template;
auto index_id = GetConstantValue(eval_context, inst.index_id, &phase);
if (!index_id.is_valid()) {
return MakeNonConstantResult(phase);
}
auto index = eval_context.insts().TryGetAs<SemIR::IntValue>(index_id);
if (!index) {
CARBON_CHECK(phase != Phase::Template,
"Template constant integer should be a literal");
return MakeNonConstantResult(phase);
}
// Array indexing is invalid if the index is constant and out of range,
// regardless of whether the array itself is constant.
const auto& index_val = eval_context.ints().Get(index->int_id);
auto aggregate_type_id = eval_context.GetConstantValueAsType(
eval_context.insts().Get(inst.array_id).type_id());
if (auto array_type =
eval_context.types().TryGetAs<SemIR::ArrayType>(aggregate_type_id)) {
if (auto bound = eval_context.insts().TryGetAs<SemIR::IntValue>(
array_type->bound_id)) {
// This awkward call to `getZExtValue` is a workaround for APInt not
// supporting comparisons between integers of different bit widths.
if (index_val.getActiveBits() > 64 ||
eval_context.ints()
.Get(bound->int_id)
.ule(index_val.getZExtValue())) {
CARBON_DIAGNOSTIC(ArrayIndexOutOfBounds, Error,
"array index `{0}` is past the end of type {1}",
TypedInt, SemIR::TypeId);
eval_context.emitter().Emit(
eval_context.GetDiagnosticLoc(inst.index_id), ArrayIndexOutOfBounds,
{.type = index->type_id, .value = index_val}, aggregate_type_id);
return SemIR::ErrorInst::SingletonConstantId;
}
}
}
auto aggregate_id = GetConstantValue(eval_context, inst.array_id, &phase);
if (!aggregate_id.is_valid()) {
return MakeNonConstantResult(phase);
}
auto aggregate =
eval_context.insts().TryGetAs<SemIR::AnyAggregateValue>(aggregate_id);
if (!aggregate) {
CARBON_CHECK(phase != Phase::Template,
"Unexpected representation for template constant aggregate");
return MakeNonConstantResult(phase);
}
auto elements = eval_context.inst_blocks().Get(aggregate->elements_id);
return eval_context.GetConstantValue(elements[index_val.getZExtValue()]);
}
// Enforces that an integer type has a valid bit width.
static auto ValidateIntType(Context& context, SemIRLoc loc,
SemIR::IntType result) -> bool {
auto bit_width =
context.insts().TryGetAs<SemIR::IntValue>(result.bit_width_id);
if (!bit_width) {
// Symbolic bit width.
return true;
}
const auto& bit_width_val = context.ints().Get(bit_width->int_id);
if (bit_width_val.isZero() ||
(context.types().IsSignedInt(bit_width->type_id) &&
bit_width_val.isNegative())) {
CARBON_DIAGNOSTIC(IntWidthNotPositive, Error,
"integer type width of {0} is not positive", TypedInt);
context.emitter().Emit(
loc, IntWidthNotPositive,
{.type = bit_width->type_id, .value = bit_width_val});
return false;
}
if (bit_width_val.ugt(IntStore::MaxIntWidth)) {
CARBON_DIAGNOSTIC(IntWidthTooLarge, Error,
"integer type width of {0} is greater than the "
"maximum supported width of {1}",
TypedInt, int);
context.emitter().Emit(loc, IntWidthTooLarge,
{.type = bit_width->type_id, .value = bit_width_val},
IntStore::MaxIntWidth);
return false;
}
return true;
}
// Forms a constant int type as an evaluation result. Requires that width_id is
// constant.
static auto MakeIntTypeResult(Context& context, SemIRLoc loc,
SemIR::IntKind int_kind, SemIR::InstId width_id,
Phase phase) -> SemIR::ConstantId {
auto result = SemIR::IntType{
.type_id = context.GetSingletonType(SemIR::TypeType::SingletonInstId),
.int_kind = int_kind,
.bit_width_id = width_id};
if (!ValidateIntType(context, loc, result)) {
return SemIR::ErrorInst::SingletonConstantId;
}
return MakeConstantResult(context, result, phase);
}
// Enforces that the bit width is 64 for a float.
static auto ValidateFloatBitWidth(Context& context, SemIRLoc loc,
SemIR::InstId inst_id) -> bool {
auto inst = context.insts().GetAs<SemIR::IntValue>(inst_id);
if (context.ints().Get(inst.int_id) == 64) {
return true;
}
CARBON_DIAGNOSTIC(CompileTimeFloatBitWidth, Error, "bit width must be 64");
context.emitter().Emit(loc, CompileTimeFloatBitWidth);
return false;
}
// Enforces that a float type has a valid bit width.
static auto ValidateFloatType(Context& context, SemIRLoc loc,
SemIR::FloatType result) -> bool {
auto bit_width =
context.insts().TryGetAs<SemIR::IntValue>(result.bit_width_id);
if (!bit_width) {
// Symbolic bit width.
return true;
}
return ValidateFloatBitWidth(context, loc, result.bit_width_id);
}
// Performs a conversion between integer types, truncating if the value doesn't
// fit in the destination type.
static auto PerformIntConvert(Context& context, SemIR::InstId arg_id,
SemIR::TypeId dest_type_id) -> SemIR::ConstantId {
auto arg_val =
context.ints().Get(context.insts().GetAs<SemIR::IntValue>(arg_id).int_id);
auto [dest_is_signed, bit_width_id] =
context.sem_ir().types().GetIntTypeInfo(dest_type_id);
if (bit_width_id.is_valid()) {
// TODO: If the value fits in the destination type, reuse the existing
// int_id rather than recomputing it. This is probably the most common case.
bool src_is_signed = context.sem_ir().types().IsSignedInt(
context.insts().Get(arg_id).type_id());
unsigned width = context.ints().Get(bit_width_id).getZExtValue();
arg_val =
src_is_signed ? arg_val.sextOrTrunc(width) : arg_val.zextOrTrunc(width);
}
return MakeIntResult(context, dest_type_id, dest_is_signed, arg_val);
}
// Performs a conversion between integer types, diagnosing if the value doesn't
// fit in the destination type.
static auto PerformCheckedIntConvert(Context& context, SemIRLoc loc,
SemIR::InstId arg_id,
SemIR::TypeId dest_type_id)
-> SemIR::ConstantId {
auto arg = context.insts().GetAs<SemIR::IntValue>(arg_id);
auto arg_val = context.ints().Get(arg.int_id);
auto [is_signed, bit_width_id] =
context.sem_ir().types().GetIntTypeInfo(dest_type_id);
auto width = bit_width_id.is_valid()
? context.ints().Get(bit_width_id).getZExtValue()
: arg_val.getBitWidth();
if (!is_signed && arg_val.isNegative()) {
CARBON_DIAGNOSTIC(
NegativeIntInUnsignedType, Error,
"negative integer value {0} converted to unsigned type {1}", TypedInt,
SemIR::TypeId);
context.emitter().Emit(loc, NegativeIntInUnsignedType,
{.type = arg.type_id, .value = arg_val},
dest_type_id);
}
unsigned arg_non_sign_bits = arg_val.getSignificantBits() - 1;
if (arg_non_sign_bits + is_signed > width) {
CARBON_DIAGNOSTIC(IntTooLargeForType, Error,
"integer value {0} too large for type {1}", TypedInt,
SemIR::TypeId);
context.emitter().Emit(loc, IntTooLargeForType,
{.type = arg.type_id, .value = arg_val},
dest_type_id);
}
return MakeConstantResult(
context, SemIR::IntValue{.type_id = dest_type_id, .int_id = arg.int_id},
Phase::Template);
}
// Issues a diagnostic for a compile-time division by zero.
static auto DiagnoseDivisionByZero(Context& context, SemIRLoc loc) -> void {
CARBON_DIAGNOSTIC(CompileTimeDivisionByZero, Error, "division by zero");
context.emitter().Emit(loc, CompileTimeDivisionByZero);
}
// Get an integer at a suitable bit-width: either `bit_width_id` if it is valid,
// or the canonical width from the value store if not.
static auto GetIntAtSuitableWidth(Context& context, IntId int_id,
IntId bit_width_id) -> llvm::APInt {
return bit_width_id.is_valid()
? context.ints().GetAtWidth(int_id, bit_width_id)
: context.ints().Get(int_id);
}
// Performs a builtin unary integer -> integer operation.
static auto PerformBuiltinUnaryIntOp(Context& context, SemIRLoc loc,
SemIR::BuiltinFunctionKind builtin_kind,
SemIR::InstId arg_id)
-> SemIR::ConstantId {
auto op = context.insts().GetAs<SemIR::IntValue>(arg_id);
auto [is_signed, bit_width_id] =
context.sem_ir().types().GetIntTypeInfo(op.type_id);
llvm::APInt op_val = GetIntAtSuitableWidth(context, op.int_id, bit_width_id);
switch (builtin_kind) {
case SemIR::BuiltinFunctionKind::IntSNegate:
if (op_val.isMinSignedValue()) {
if (bit_width_id.is_valid()) {
CARBON_DIAGNOSTIC(CompileTimeIntegerNegateOverflow, Error,
"integer overflow in negation of {0}", TypedInt);
context.emitter().Emit(loc, CompileTimeIntegerNegateOverflow,
{.type = op.type_id, .value = op_val});
} else {
// Widen the integer so we don't overflow into the sign bit.
op_val = op_val.sext(op_val.getBitWidth() +
llvm::APInt::APINT_BITS_PER_WORD);
}
}
op_val.negate();
break;
case SemIR::BuiltinFunctionKind::IntUNegate:
CARBON_CHECK(bit_width_id.is_valid(), "Unsigned negate on unsized int");
op_val.negate();
break;
case SemIR::BuiltinFunctionKind::IntComplement:
// TODO: Should we have separate builtins for signed and unsigned
// complement? Like with signed/unsigned negate, these operations do
// different things to the integer value, even though they do the same
// thing to the bits. We treat IntLiteral complement as signed complement,
// given that the result of unsigned complement depends on the bit width.
op_val.flipAllBits();
break;
default:
CARBON_FATAL("Unexpected builtin kind");
}
return MakeIntResult(context, op.type_id, is_signed, std::move(op_val));
}
namespace {
// A pair of APInts that are the operands of a binary operator. We use an
// aggregate rather than `std::pair` to allow RVO of the individual ints.
struct APIntBinaryOperands {
llvm::APInt lhs;
llvm::APInt rhs;
};
} // namespace
// Get a pair of integers at the same suitable bit-width: either their actual
// width if they have a fixed width, or the smallest canonical width in which
// they both fit otherwise.
static auto GetIntsAtSuitableWidth(Context& context, IntId lhs_id, IntId rhs_id,
IntId bit_width_id) -> APIntBinaryOperands {
// Unsized operands: take the wider of the bit widths.
if (!bit_width_id.is_valid()) {
APIntBinaryOperands result = {.lhs = context.ints().Get(lhs_id),
.rhs = context.ints().Get(rhs_id)};
if (result.lhs.getBitWidth() != result.rhs.getBitWidth()) {
if (result.lhs.getBitWidth() > result.rhs.getBitWidth()) {
result.rhs = result.rhs.sext(result.lhs.getBitWidth());
} else {
result.lhs = result.lhs.sext(result.rhs.getBitWidth());
}
}
return result;
}
return {.lhs = context.ints().GetAtWidth(lhs_id, bit_width_id),
.rhs = context.ints().GetAtWidth(rhs_id, bit_width_id)};
}
namespace {
// The result of performing a binary int operation.
struct BinaryIntOpResult {
llvm::APInt result_val;
bool overflow;
Lex::TokenKind op_token;
};
} // namespace
// Computes the result of a homogeneous binary (int, int) -> int operation.
static auto ComputeBinaryIntOpResult(SemIR::BuiltinFunctionKind builtin_kind,
const llvm::APInt& lhs_val,
const llvm::APInt& rhs_val)
-> BinaryIntOpResult {
llvm::APInt result_val;
bool overflow = false;
Lex::TokenKind op_token = Lex::TokenKind::Not;
switch (builtin_kind) {
// Arithmetic.
case SemIR::BuiltinFunctionKind::IntSAdd:
result_val = lhs_val.sadd_ov(rhs_val, overflow);
op_token = Lex::TokenKind::Plus;
break;
case SemIR::BuiltinFunctionKind::IntSSub:
result_val = lhs_val.ssub_ov(rhs_val, overflow);
op_token = Lex::TokenKind::Minus;
break;
case SemIR::BuiltinFunctionKind::IntSMul:
result_val = lhs_val.smul_ov(rhs_val, overflow);
op_token = Lex::TokenKind::Star;
break;
case SemIR::BuiltinFunctionKind::IntSDiv:
result_val = lhs_val.sdiv_ov(rhs_val, overflow);
op_token = Lex::TokenKind::Slash;
break;
case SemIR::BuiltinFunctionKind::IntSMod:
result_val = lhs_val.srem(rhs_val);
// LLVM weirdly lacks `srem_ov`, so we work it out for ourselves:
// <signed min> % -1 overflows because <signed min> / -1 overflows.
overflow = lhs_val.isMinSignedValue() && rhs_val.isAllOnes();
op_token = Lex::TokenKind::Percent;
break;
case SemIR::BuiltinFunctionKind::IntUAdd:
result_val = lhs_val + rhs_val;
op_token = Lex::TokenKind::Plus;
break;
case SemIR::BuiltinFunctionKind::IntUSub:
result_val = lhs_val - rhs_val;
op_token = Lex::TokenKind::Minus;
break;
case SemIR::BuiltinFunctionKind::IntUMul:
result_val = lhs_val * rhs_val;
op_token = Lex::TokenKind::Star;
break;
case SemIR::BuiltinFunctionKind::IntUDiv:
result_val = lhs_val.udiv(rhs_val);
op_token = Lex::TokenKind::Slash;
break;
case SemIR::BuiltinFunctionKind::IntUMod:
result_val = lhs_val.urem(rhs_val);
op_token = Lex::TokenKind::Percent;
break;
// Bitwise.
case SemIR::BuiltinFunctionKind::IntAnd:
result_val = lhs_val & rhs_val;
op_token = Lex::TokenKind::And;
break;
case SemIR::BuiltinFunctionKind::IntOr:
result_val = lhs_val | rhs_val;
op_token = Lex::TokenKind::Pipe;
break;
case SemIR::BuiltinFunctionKind::IntXor:
result_val = lhs_val ^ rhs_val;
op_token = Lex::TokenKind::Caret;
break;
case SemIR::BuiltinFunctionKind::IntLeftShift:
case SemIR::BuiltinFunctionKind::IntRightShift:
CARBON_FATAL("Non-homogeneous operation handled separately.");
default:
CARBON_FATAL("Unexpected operation kind.");
}
return {.result_val = std::move(result_val),
.overflow = overflow,
.op_token = op_token};
}
// Performs a builtin integer bit shift operation.
static auto PerformBuiltinIntShiftOp(Context& context, SemIRLoc loc,
SemIR::BuiltinFunctionKind builtin_kind,
SemIR::InstId lhs_id, SemIR::InstId rhs_id)
-> SemIR::ConstantId {
auto lhs = context.insts().GetAs<SemIR::IntValue>(lhs_id);
auto rhs = context.insts().GetAs<SemIR::IntValue>(rhs_id);
auto [lhs_is_signed, lhs_bit_width_id] =
context.sem_ir().types().GetIntTypeInfo(lhs.type_id);
llvm::APInt lhs_val =
GetIntAtSuitableWidth(context, lhs.int_id, lhs_bit_width_id);
const auto& rhs_orig_val = context.ints().Get(rhs.int_id);
if (lhs_bit_width_id.is_valid() && rhs_orig_val.uge(lhs_val.getBitWidth())) {
CARBON_DIAGNOSTIC(
CompileTimeShiftOutOfRange, Error,
"shift distance >= type width of {0} in `{1} {2:<<|>>} {3}`", unsigned,
TypedInt, BoolAsSelect, TypedInt);
context.emitter().Emit(
loc, CompileTimeShiftOutOfRange, lhs_val.getBitWidth(),
{.type = lhs.type_id, .value = lhs_val},
builtin_kind == SemIR::BuiltinFunctionKind::IntLeftShift,
{.type = rhs.type_id, .value = rhs_orig_val});
// TODO: Is it useful to recover by returning 0 or -1?
return SemIR::ErrorInst::SingletonConstantId;
}
if (rhs_orig_val.isNegative() &&
context.sem_ir().types().IsSignedInt(rhs.type_id)) {
CARBON_DIAGNOSTIC(CompileTimeShiftNegative, Error,
"shift distance negative in `{0} {1:<<|>>} {2}`",
TypedInt, BoolAsSelect, TypedInt);
context.emitter().Emit(
loc, CompileTimeShiftNegative, {.type = lhs.type_id, .value = lhs_val},
builtin_kind == SemIR::BuiltinFunctionKind::IntLeftShift,
{.type = rhs.type_id, .value = rhs_orig_val});
// TODO: Is it useful to recover by returning 0 or -1?
return SemIR::ErrorInst::SingletonConstantId;
}
llvm::APInt result_val;
if (builtin_kind == SemIR::BuiltinFunctionKind::IntLeftShift) {
if (!lhs_bit_width_id.is_valid() && !lhs_val.isZero()) {
// Ensure we don't generate a ridiculously large integer through a bit
// shift.
auto width = rhs_orig_val.trySExtValue();
if (!width ||
*width > IntStore::MaxIntWidth - lhs_val.getSignificantBits()) {
CARBON_DIAGNOSTIC(CompileTimeUnsizedShiftOutOfRange, Error,
"shift distance of {0} would result in an "
"integer whose width is greater than the "
"maximum supported width of {1}",
TypedInt, int);
context.emitter().Emit(loc, CompileTimeUnsizedShiftOutOfRange,
{.type = rhs.type_id, .value = rhs_orig_val},
IntStore::MaxIntWidth);
return SemIR::ErrorInst::SingletonConstantId;
}
lhs_val = lhs_val.sext(
IntStore::CanonicalBitWidth(lhs_val.getSignificantBits() + *width));
}
result_val =
lhs_val.shl(rhs_orig_val.getLimitedValue(lhs_val.getBitWidth()));
} else if (lhs_is_signed) {
result_val =
lhs_val.ashr(rhs_orig_val.getLimitedValue(lhs_val.getBitWidth()));
} else {
CARBON_CHECK(lhs_bit_width_id.is_valid(), "Logical shift on unsized int");
result_val =
lhs_val.lshr(rhs_orig_val.getLimitedValue(lhs_val.getBitWidth()));
}
return MakeIntResult(context, lhs.type_id, lhs_is_signed,
std::move(result_val));
}
// Performs a homogeneous builtin binary integer -> integer operation.
static auto PerformBuiltinBinaryIntOp(Context& context, SemIRLoc loc,
SemIR::BuiltinFunctionKind builtin_kind,
SemIR::InstId lhs_id,
SemIR::InstId rhs_id)
-> SemIR::ConstantId {
auto lhs = context.insts().GetAs<SemIR::IntValue>(lhs_id);
auto rhs = context.insts().GetAs<SemIR::IntValue>(rhs_id);
CARBON_CHECK(rhs.type_id == lhs.type_id, "Heterogeneous builtin integer op!");
auto type_id = lhs.type_id;
auto [is_signed, bit_width_id] =
context.sem_ir().types().GetIntTypeInfo(type_id);
auto [lhs_val, rhs_val] =
GetIntsAtSuitableWidth(context, lhs.int_id, rhs.int_id, bit_width_id);
// Check for division by zero.
switch (builtin_kind) {
case SemIR::BuiltinFunctionKind::IntSDiv:
case SemIR::BuiltinFunctionKind::IntSMod:
case SemIR::BuiltinFunctionKind::IntUDiv:
case SemIR::BuiltinFunctionKind::IntUMod:
if (rhs_val.isZero()) {
DiagnoseDivisionByZero(context, loc);
return SemIR::ErrorInst::SingletonConstantId;
}
break;
default:
break;
}
BinaryIntOpResult result =
ComputeBinaryIntOpResult(builtin_kind, lhs_val, rhs_val);
if (result.overflow && !bit_width_id.is_valid()) {
// Retry with a larger bit width. Most operations can only overflow by one
// bit, but signed n-bit multiplication can overflow to 2n-1 bits. We don't
// need to handle unsigned multiplication here because it's not permitted
// for unsized integers.
//
// Note that we speculatively first perform the calculation in the width of
// the wider operand: smaller operations are faster and overflow to a wider
// integer is unlikely to be needed, especially given that the width will
// have been rounded up to a multiple of 64 bits by the int store.
CARBON_CHECK(builtin_kind != SemIR::BuiltinFunctionKind::IntUMul,
"Unsigned arithmetic requires a fixed bitwidth");
int new_width =
builtin_kind == SemIR::BuiltinFunctionKind::IntSMul
? lhs_val.getBitWidth() * 2
: IntStore::CanonicalBitWidth(lhs_val.getBitWidth() + 1);
new_width = std::min(new_width, IntStore::MaxIntWidth);
lhs_val = context.ints().GetAtWidth(lhs.int_id, new_width);
rhs_val = context.ints().GetAtWidth(rhs.int_id, new_width);
// Note that this can in theory still overflow if we limited `new_width` to
// `MaxIntWidth`. In that case we fall through to the signed overflow
// diagnostic below.
result = ComputeBinaryIntOpResult(builtin_kind, lhs_val, rhs_val);
CARBON_CHECK(!result.overflow || new_width == IntStore::MaxIntWidth);
}
if (result.overflow) {
CARBON_DIAGNOSTIC(CompileTimeIntegerOverflow, Error,
"integer overflow in calculation `{0} {1} {2}`", TypedInt,
Lex::TokenKind, TypedInt);
context.emitter().Emit(loc, CompileTimeIntegerOverflow,
{.type = type_id, .value = lhs_val}, result.op_token,
{.type = type_id, .value = rhs_val});
}
return MakeIntResult(context, type_id, is_signed,
std::move(result.result_val));
}
// Performs a builtin integer comparison.
static auto PerformBuiltinIntComparison(Context& context,
SemIR::BuiltinFunctionKind builtin_kind,
SemIR::InstId lhs_id,
SemIR::InstId rhs_id,
SemIR::TypeId bool_type_id)
-> SemIR::ConstantId {
auto lhs = context.insts().GetAs<SemIR::IntValue>(lhs_id);
auto rhs = context.insts().GetAs<SemIR::IntValue>(rhs_id);
llvm::APInt lhs_val = context.ints().Get(lhs.int_id);
llvm::APInt rhs_val = context.ints().Get(rhs.int_id);
bool result;
switch (builtin_kind) {
case SemIR::BuiltinFunctionKind::IntEq:
result = (lhs_val == rhs_val);
break;
case SemIR::BuiltinFunctionKind::IntNeq:
result = (lhs_val != rhs_val);
break;
case SemIR::BuiltinFunctionKind::IntLess:
result = lhs_val.slt(rhs_val);
break;
case SemIR::BuiltinFunctionKind::IntLessEq:
result = lhs_val.sle(rhs_val);
break;
case SemIR::BuiltinFunctionKind::IntGreater:
result = lhs_val.sgt(rhs_val);
break;
case SemIR::BuiltinFunctionKind::IntGreaterEq:
result = lhs_val.sge(rhs_val);
break;
default:
CARBON_FATAL("Unexpected operation kind.");
}
return MakeBoolResult(context, bool_type_id, result);
}
// Performs a builtin unary float -> float operation.
static auto PerformBuiltinUnaryFloatOp(Context& context,
SemIR::BuiltinFunctionKind builtin_kind,
SemIR::InstId arg_id)
-> SemIR::ConstantId {
auto op = context.insts().GetAs<SemIR::FloatLiteral>(arg_id);
auto op_val = context.floats().Get(op.float_id);
switch (builtin_kind) {
case SemIR::BuiltinFunctionKind::FloatNegate:
op_val.changeSign();
break;
default:
CARBON_FATAL("Unexpected builtin kind");
}
return MakeFloatResult(context, op.type_id, std::move(op_val));
}
// Performs a builtin binary float -> float operation.
static auto PerformBuiltinBinaryFloatOp(Context& context,
SemIR::BuiltinFunctionKind builtin_kind,
SemIR::InstId lhs_id,
SemIR::InstId rhs_id)
-> SemIR::ConstantId {
auto lhs = context.insts().GetAs<SemIR::FloatLiteral>(lhs_id);
auto rhs = context.insts().GetAs<SemIR::FloatLiteral>(rhs_id);
auto lhs_val = context.floats().Get(lhs.float_id);
auto rhs_val = context.floats().Get(rhs.float_id);
llvm::APFloat result_val(lhs_val.getSemantics());
switch (builtin_kind) {
case SemIR::BuiltinFunctionKind::FloatAdd:
result_val = lhs_val + rhs_val;
break;
case SemIR::BuiltinFunctionKind::FloatSub:
result_val = lhs_val - rhs_val;
break;
case SemIR::BuiltinFunctionKind::FloatMul:
result_val = lhs_val * rhs_val;
break;
case SemIR::BuiltinFunctionKind::FloatDiv:
result_val = lhs_val / rhs_val;
break;
default:
CARBON_FATAL("Unexpected operation kind.");
}
return MakeFloatResult(context, lhs.type_id, std::move(result_val));
}
// Performs a builtin float comparison.
static auto PerformBuiltinFloatComparison(
Context& context, SemIR::BuiltinFunctionKind builtin_kind,
SemIR::InstId lhs_id, SemIR::InstId rhs_id, SemIR::TypeId bool_type_id)
-> SemIR::ConstantId {
auto lhs = context.insts().GetAs<SemIR::FloatLiteral>(lhs_id);
auto rhs = context.insts().GetAs<SemIR::FloatLiteral>(rhs_id);
const auto& lhs_val = context.floats().Get(lhs.float_id);
const auto& rhs_val = context.floats().Get(rhs.float_id);
bool result;
switch (builtin_kind) {
case SemIR::BuiltinFunctionKind::FloatEq:
result = (lhs_val == rhs_val);
break;
case SemIR::BuiltinFunctionKind::FloatNeq:
result = (lhs_val != rhs_val);
break;
case SemIR::BuiltinFunctionKind::FloatLess:
result = lhs_val < rhs_val;
break;
case SemIR::BuiltinFunctionKind::FloatLessEq:
result = lhs_val <= rhs_val;
break;
case SemIR::BuiltinFunctionKind::FloatGreater:
result = lhs_val > rhs_val;
break;
case SemIR::BuiltinFunctionKind::FloatGreaterEq:
result = lhs_val >= rhs_val;
break;
default:
CARBON_FATAL("Unexpected operation kind.");
}
return MakeBoolResult(context, bool_type_id, result);
}
// Performs a builtin boolean comparison.
static auto PerformBuiltinBoolComparison(
Context& context, SemIR::BuiltinFunctionKind builtin_kind,
SemIR::InstId lhs_id, SemIR::InstId rhs_id, SemIR::TypeId bool_type_id) {
bool lhs = context.insts().GetAs<SemIR::BoolLiteral>(lhs_id).value.ToBool();
bool rhs = context.insts().GetAs<SemIR::BoolLiteral>(rhs_id).value.ToBool();
return MakeBoolResult(context, bool_type_id,
builtin_kind == SemIR::BuiltinFunctionKind::BoolEq
? lhs == rhs
: lhs != rhs);
}
// Returns a constant for a call to a builtin function.
static auto MakeConstantForBuiltinCall(Context& context, SemIRLoc loc,
SemIR::Call call,
SemIR::BuiltinFunctionKind builtin_kind,
llvm::ArrayRef<SemIR::InstId> arg_ids,
Phase phase) -> SemIR::ConstantId {
switch (builtin_kind) {
case SemIR::BuiltinFunctionKind::None:
CARBON_FATAL("Not a builtin function.");
case SemIR::BuiltinFunctionKind::PrintChar:
case SemIR::BuiltinFunctionKind::PrintInt:
case SemIR::BuiltinFunctionKind::ReadChar: {
// These are runtime-only builtins.
// TODO: Consider tracking this on the `BuiltinFunctionKind`.
return SemIR::ConstantId::NotConstant;
}
case SemIR::BuiltinFunctionKind::IntLiteralMakeType: {
return context.constant_values().Get(
SemIR::IntLiteralType::SingletonInstId);
}
case SemIR::BuiltinFunctionKind::IntMakeTypeSigned: {
return MakeIntTypeResult(context, loc, SemIR::IntKind::Signed, arg_ids[0],
phase);
}
case SemIR::BuiltinFunctionKind::IntMakeTypeUnsigned: {
return MakeIntTypeResult(context, loc, SemIR::IntKind::Unsigned,
arg_ids[0], phase);
}
case SemIR::BuiltinFunctionKind::FloatMakeType: {
// TODO: Support a symbolic constant width.
if (phase != Phase::Template) {
break;
}
if (!ValidateFloatBitWidth(context, loc, arg_ids[0])) {
return SemIR::ErrorInst::SingletonConstantId;
}
return context.constant_values().Get(
SemIR::LegacyFloatType::SingletonInstId);
}
case SemIR::BuiltinFunctionKind::BoolMakeType: {
return context.constant_values().Get(SemIR::BoolType::SingletonInstId);
}
// Integer conversions.
case SemIR::BuiltinFunctionKind::IntConvert: {
if (phase == Phase::Symbolic) {
return MakeConstantResult(context, call, phase);
}
return PerformIntConvert(context, arg_ids[0], call.type_id);
}
case SemIR::BuiltinFunctionKind::IntConvertChecked: {
if (phase == Phase::Symbolic) {
return MakeConstantResult(context, call, phase);
}
return PerformCheckedIntConvert(context, loc, arg_ids[0], call.type_id);
}
// Unary integer -> integer operations.
case SemIR::BuiltinFunctionKind::IntSNegate:
case SemIR::BuiltinFunctionKind::IntUNegate:
case SemIR::BuiltinFunctionKind::IntComplement: {
if (phase != Phase::Template) {
break;
}
return PerformBuiltinUnaryIntOp(context, loc, builtin_kind, arg_ids[0]);
}
// Homogeneous binary integer -> integer operations.
case SemIR::BuiltinFunctionKind::IntSAdd:
case SemIR::BuiltinFunctionKind::IntSSub:
case SemIR::BuiltinFunctionKind::IntSMul:
case SemIR::BuiltinFunctionKind::IntSDiv:
case SemIR::BuiltinFunctionKind::IntSMod:
case SemIR::BuiltinFunctionKind::IntUAdd:
case SemIR::BuiltinFunctionKind::IntUSub:
case SemIR::BuiltinFunctionKind::IntUMul:
case SemIR::BuiltinFunctionKind::IntUDiv:
case SemIR::BuiltinFunctionKind::IntUMod:
case SemIR::BuiltinFunctionKind::IntAnd:
case SemIR::BuiltinFunctionKind::IntOr:
case SemIR::BuiltinFunctionKind::IntXor: {
if (phase != Phase::Template) {
break;
}
return PerformBuiltinBinaryIntOp(context, loc, builtin_kind, arg_ids[0],
arg_ids[1]);
}
// Bit shift operations.
case SemIR::BuiltinFunctionKind::IntLeftShift:
case SemIR::BuiltinFunctionKind::IntRightShift: {
if (phase != Phase::Template) {
break;
}
return PerformBuiltinIntShiftOp(context, loc, builtin_kind, arg_ids[0],
arg_ids[1]);
}
// Integer comparisons.
case SemIR::BuiltinFunctionKind::IntEq:
case SemIR::BuiltinFunctionKind::IntNeq:
case SemIR::BuiltinFunctionKind::IntLess:
case SemIR::BuiltinFunctionKind::IntLessEq:
case SemIR::BuiltinFunctionKind::IntGreater:
case SemIR::BuiltinFunctionKind::IntGreaterEq: {
if (phase != Phase::Template) {
break;
}
return PerformBuiltinIntComparison(context, builtin_kind, arg_ids[0],
arg_ids[1], call.type_id);
}
// Unary float -> float operations.
case SemIR::BuiltinFunctionKind::FloatNegate: {
if (phase != Phase::Template) {
break;
}
return PerformBuiltinUnaryFloatOp(context, builtin_kind, arg_ids[0]);
}
// Binary float -> float operations.
case SemIR::BuiltinFunctionKind::FloatAdd:
case SemIR::BuiltinFunctionKind::FloatSub:
case SemIR::BuiltinFunctionKind::FloatMul:
case SemIR::BuiltinFunctionKind::FloatDiv: {
if (phase != Phase::Template) {
break;
}
return PerformBuiltinBinaryFloatOp(context, builtin_kind, arg_ids[0],
arg_ids[1]);
}
// Float comparisons.
case SemIR::BuiltinFunctionKind::FloatEq:
case SemIR::BuiltinFunctionKind::FloatNeq:
case SemIR::BuiltinFunctionKind::FloatLess:
case SemIR::BuiltinFunctionKind::FloatLessEq:
case SemIR::BuiltinFunctionKind::FloatGreater:
case SemIR::BuiltinFunctionKind::FloatGreaterEq: {
if (phase != Phase::Template) {
break;
}
return PerformBuiltinFloatComparison(context, builtin_kind, arg_ids[0],
arg_ids[1], call.type_id);
}
// Bool comparisons.
case SemIR::BuiltinFunctionKind::BoolEq:
case SemIR::BuiltinFunctionKind::BoolNeq: {
if (phase != Phase::Template) {
break;
}
return PerformBuiltinBoolComparison(context, builtin_kind, arg_ids[0],
arg_ids[1], call.type_id);
}
}
return SemIR::ConstantId::NotConstant;
}
// Makes a constant for a call instruction.
static auto MakeConstantForCall(EvalContext& eval_context, SemIRLoc loc,
SemIR::Call call) -> SemIR::ConstantId {
Phase phase = Phase::Template;
// A call with an invalid argument list is used to represent an erroneous
// call.
//
// TODO: Use a better representation for this.
if (call.args_id == SemIR::InstBlockId::Invalid) {
return SemIR::ErrorInst::SingletonConstantId;
}
// Find the constant value of the callee.
bool has_constant_callee = ReplaceFieldWithConstantValue(
eval_context, &call, &SemIR::Call::callee_id, &phase);
auto callee_function =
SemIR::GetCalleeFunction(eval_context.sem_ir(), call.callee_id);
auto builtin_kind = SemIR::BuiltinFunctionKind::None;
if (callee_function.function_id.is_valid()) {
// Calls to builtins might be constant.
builtin_kind = eval_context.functions()
.Get(callee_function.function_id)
.builtin_function_kind;
if (builtin_kind == SemIR::BuiltinFunctionKind::None) {
// TODO: Eventually we'll want to treat some kinds of non-builtin
// functions as producing constants.
return SemIR::ConstantId::NotConstant;
}
} else {
// Calls to non-functions, such as calls to generic entity names, might be
// constant.
}
// Find the argument values and the return type.
bool has_constant_operands =
has_constant_callee &&
ReplaceFieldWithConstantValue(eval_context, &call, &SemIR::Call::type_id,
&phase) &&
ReplaceFieldWithConstantValue(eval_context, &call, &SemIR::Call::args_id,
&phase);
if (phase == Phase::UnknownDueToError) {
return SemIR::ErrorInst::SingletonConstantId;
}
// If any operand of the call is non-constant, the call is non-constant.
// TODO: Some builtin calls might allow some operands to be non-constant.
if (!has_constant_operands) {
if (builtin_kind.IsCompTimeOnly(
eval_context.sem_ir(), eval_context.inst_blocks().Get(call.args_id),
call.type_id)) {
CARBON_DIAGNOSTIC(NonConstantCallToCompTimeOnlyFunction, Error,
"non-constant call to compile-time-only function");
CARBON_DIAGNOSTIC(CompTimeOnlyFunctionHere, Note,
"compile-time-only function declared here");
eval_context.emitter()
.Build(loc, NonConstantCallToCompTimeOnlyFunction)
.Note(eval_context.functions()
.Get(callee_function.function_id)
.latest_decl_id(),
CompTimeOnlyFunctionHere)
.Emit();
}
return SemIR::ConstantId::NotConstant;
}
// Handle calls to builtins.
if (builtin_kind != SemIR::BuiltinFunctionKind::None) {
return MakeConstantForBuiltinCall(
eval_context.context(), loc, call, builtin_kind,
eval_context.inst_blocks().Get(call.args_id), phase);
}
return SemIR::ConstantId::NotConstant;
}
// Creates a FacetType constant.
static auto MakeFacetTypeResult(Context& context,
const SemIR::FacetTypeInfo& info, Phase phase)
-> SemIR::ConstantId {
SemIR::FacetTypeId facet_type_id = context.facet_types().Add(info);
return MakeConstantResult(
context,
SemIR::FacetType{.type_id = SemIR::TypeType::SingletonTypeId,
.facet_type_id = facet_type_id},
phase);
}
// Implementation for `TryEvalInst`, wrapping `Context` with `EvalContext`.
static auto TryEvalInstInContext(EvalContext& eval_context,
SemIR::InstId inst_id, SemIR::Inst inst)
-> SemIR::ConstantId {
// TODO: Ensure we have test coverage for each of these cases that can result
// in a constant, once those situations are all reachable.
CARBON_KIND_SWITCH(inst) {
// These cases are constants if their operands are.
case SemIR::AddrOf::Kind:
return RebuildIfFieldsAreConstant(eval_context, inst,
&SemIR::AddrOf::type_id,
&SemIR::AddrOf::lvalue_id);
case CARBON_KIND(SemIR::ArrayType array_type): {
return RebuildAndValidateIfFieldsAreConstant(
eval_context, inst,
[&](SemIR::ArrayType result) {
auto bound_id = array_type.bound_id;
auto bound_inst = eval_context.insts().Get(result.bound_id);
auto int_bound = bound_inst.TryAs<SemIR::IntValue>();
if (!int_bound) {
CARBON_CHECK(eval_context.constant_values()
.Get(result.bound_id)
.is_symbolic(),
"Unexpected inst {0} for template constant int",
bound_inst);
return true;
}
// TODO: We should check that the size of the resulting array type
// fits in 64 bits, not just that the bound does. Should we use a
// 32-bit limit for 32-bit targets?
const auto& bound_val = eval_context.ints().Get(int_bound->int_id);
if (eval_context.types().IsSignedInt(int_bound->type_id) &&
bound_val.isNegative()) {
CARBON_DIAGNOSTIC(ArrayBoundNegative, Error,
"array bound of {0} is negative", TypedInt);
eval_context.emitter().Emit(
eval_context.GetDiagnosticLoc(bound_id), ArrayBoundNegative,
{.type = int_bound->type_id, .value = bound_val});
return false;
}
if (bound_val.getActiveBits() > 64) {
CARBON_DIAGNOSTIC(ArrayBoundTooLarge, Error,
"array bound of {0} is too large", TypedInt);
eval_context.emitter().Emit(
eval_context.GetDiagnosticLoc(bound_id), ArrayBoundTooLarge,
{.type = int_bound->type_id, .value = bound_val});
return false;
}
return true;
},
&SemIR::ArrayType::bound_id, &SemIR::ArrayType::element_type_id);
}
case SemIR::AssociatedEntity::Kind:
return RebuildIfFieldsAreConstant(eval_context, inst,
&SemIR::AssociatedEntity::type_id);
case SemIR::AssociatedEntityType::Kind:
return RebuildIfFieldsAreConstant(
eval_context, inst, &SemIR::AssociatedEntityType::interface_type_id,
&SemIR::AssociatedEntityType::entity_type_id);
case SemIR::BoundMethod::Kind:
return RebuildIfFieldsAreConstant(eval_context, inst,
&SemIR::BoundMethod::type_id,
&SemIR::BoundMethod::object_id,
&SemIR::BoundMethod::function_decl_id);
case SemIR::ClassType::Kind:
return RebuildIfFieldsAreConstant(eval_context, inst,
&SemIR::ClassType::specific_id);
case SemIR::CompleteTypeWitness::Kind:
return RebuildIfFieldsAreConstant(
eval_context, inst, &SemIR::CompleteTypeWitness::object_repr_id);
case SemIR::FacetValue::Kind:
return RebuildIfFieldsAreConstant(eval_context, inst,
&SemIR::FacetValue::type_id,
&SemIR::FacetValue::type_inst_id,
&SemIR::FacetValue::witness_inst_id);
case SemIR::FunctionType::Kind:
return RebuildIfFieldsAreConstant(eval_context, inst,
&SemIR::FunctionType::specific_id);
case SemIR::GenericClassType::Kind:
return RebuildIfFieldsAreConstant(
eval_context, inst, &SemIR::GenericClassType::enclosing_specific_id);
case SemIR::GenericInterfaceType::Kind:
return RebuildIfFieldsAreConstant(
eval_context, inst,
&SemIR::GenericInterfaceType::enclosing_specific_id);
case SemIR::ImplWitness::Kind:
// We intentionally don't replace the `elements_id` field here. We want to
// track that specific InstBlock in particular, not coalesce blocks with
// the same members. That block may get updated, and we want to pick up
// those changes.
return RebuildIfFieldsAreConstant(eval_context, inst,
&SemIR::ImplWitness::specific_id);
case CARBON_KIND(SemIR::IntType int_type): {
return RebuildAndValidateIfFieldsAreConstant(
eval_context, inst,
[&](SemIR::IntType result) {
return ValidateIntType(
eval_context.context(),
eval_context.GetDiagnosticLoc({inst_id, int_type.bit_width_id}),
result);
},
&SemIR::IntType::bit_width_id);
}
case SemIR::PointerType::Kind:
return RebuildIfFieldsAreConstant(eval_context, inst,
&SemIR::PointerType::pointee_id);
case CARBON_KIND(SemIR::FloatType float_type): {
return RebuildAndValidateIfFieldsAreConstant(
eval_context, inst,
[&](SemIR::FloatType result) {
return ValidateFloatType(eval_context.context(),
eval_context.GetDiagnosticLoc(
{inst_id, float_type.bit_width_id}),
result);
},
&SemIR::FloatType::bit_width_id);
}
case SemIR::SpecificFunction::Kind:
return RebuildIfFieldsAreConstant(eval_context, inst,
&SemIR::SpecificFunction::callee_id,
&SemIR::SpecificFunction::specific_id);
case SemIR::StructType::Kind:
return RebuildIfFieldsAreConstant(eval_context, inst,
&SemIR::StructType::fields_id);
case SemIR::StructValue::Kind:
return RebuildIfFieldsAreConstant(eval_context, inst,
&SemIR::StructValue::type_id,
&SemIR::StructValue::elements_id);
case SemIR::TupleType::Kind:
return RebuildIfFieldsAreConstant(eval_context, inst,
&SemIR::TupleType::elements_id);
case SemIR::TupleValue::Kind:
return RebuildIfFieldsAreConstant(eval_context, inst,
&SemIR::TupleValue::type_id,
&SemIR::TupleValue::elements_id);
case SemIR::UnboundElementType::Kind:
return RebuildIfFieldsAreConstant(
eval_context, inst, &SemIR::UnboundElementType::class_type_id,
&SemIR::UnboundElementType::element_type_id);
// Initializers evaluate to a value of the object representation.
case SemIR::ArrayInit::Kind:
// TODO: Add an `ArrayValue` to represent a constant array object
// representation instead of using a `TupleValue`.
return RebuildInitAsValue(eval_context, inst, SemIR::TupleValue::Kind);
case SemIR::ClassInit::Kind:
// TODO: Add a `ClassValue` to represent a constant class object
// representation instead of using a `StructValue`.
return RebuildInitAsValue(eval_context, inst, SemIR::StructValue::Kind);
case SemIR::StructInit::Kind:
return RebuildInitAsValue(eval_context, inst, SemIR::StructValue::Kind);
case SemIR::TupleInit::Kind:
return RebuildInitAsValue(eval_context, inst, SemIR::TupleValue::Kind);
case SemIR::Vtable::Kind:
return RebuildIfFieldsAreConstant(eval_context, inst,
&SemIR::Vtable::virtual_functions_id);
case SemIR::AutoType::Kind:
case SemIR::BoolType::Kind:
case SemIR::BoundMethodType::Kind:
case SemIR::ErrorInst::Kind:
case SemIR::IntLiteralType::Kind:
case SemIR::LegacyFloatType::Kind:
case SemIR::NamespaceType::Kind:
case SemIR::SpecificFunctionType::Kind:
case SemIR::StringType::Kind:
case SemIR::TypeType::Kind:
case SemIR::VtableType::Kind:
case SemIR::WitnessType::Kind:
// Builtins are always template constants.
return MakeConstantResult(eval_context.context(), inst, Phase::Template);
case CARBON_KIND(SemIR::FunctionDecl fn_decl): {
return TransformIfFieldsAreConstant(
eval_context, fn_decl,
[&](SemIR::FunctionDecl result) {
return SemIR::StructValue{.type_id = result.type_id,
.elements_id = SemIR::InstBlockId::Empty};
},
&SemIR::FunctionDecl::type_id);
}
case CARBON_KIND(SemIR::ClassDecl class_decl): {
// If the class has generic parameters, we don't produce a class type, but
// a callable whose return value is a class type.
if (eval_context.classes().Get(class_decl.class_id).has_parameters()) {
return TransformIfFieldsAreConstant(
eval_context, class_decl,
[&](SemIR::ClassDecl result) {
return SemIR::StructValue{
.type_id = result.type_id,
.elements_id = SemIR::InstBlockId::Empty};
},
&SemIR::ClassDecl::type_id);
}
// A non-generic class declaration evaluates to the class type.
return MakeConstantResult(
eval_context.context(),
SemIR::ClassType{.type_id = SemIR::TypeType::SingletonTypeId,
.class_id = class_decl.class_id,
.specific_id = SemIR::SpecificId::Invalid},
Phase::Template);
}
case CARBON_KIND(SemIR::FacetType facet_type): {
Phase phase = Phase::Template;
SemIR::FacetTypeInfo info = GetConstantFacetTypeInfo(
eval_context, facet_type.facet_type_id, &phase);
info.Canonicalize();
// TODO: Reuse `inst` if we can detect that nothing has changed.
return MakeFacetTypeResult(eval_context.context(), info, phase);
}
case CARBON_KIND(SemIR::InterfaceDecl interface_decl): {
// If the interface has generic parameters, we don't produce an interface
// type, but a callable whose return value is an interface type.
if (eval_context.interfaces()
.Get(interface_decl.interface_id)
.has_parameters()) {
return TransformIfFieldsAreConstant(
eval_context, interface_decl,
[&](SemIR::InterfaceDecl result) {
return SemIR::StructValue{
.type_id = result.type_id,
.elements_id = SemIR::InstBlockId::Empty};
},
&SemIR::InterfaceDecl::type_id);
}
// A non-generic interface declaration evaluates to a facet type.
return MakeConstantResult(
eval_context.context(),
eval_context.context().FacetTypeFromInterface(
interface_decl.interface_id, SemIR::SpecificId::Invalid),
Phase::Template);
}
case CARBON_KIND(SemIR::SpecificConstant specific): {
// Pull the constant value out of the specific.
return SemIR::GetConstantValueInSpecific(
eval_context.sem_ir(), specific.specific_id, specific.inst_id);
}
// These cases are treated as being the unique canonical definition of the
// corresponding constant value.
// TODO: This doesn't properly handle redeclarations. Consider adding a
// corresponding `Value` inst for each of these cases, or returning the
// first declaration.
case SemIR::AdaptDecl::Kind:
case SemIR::AssociatedConstantDecl::Kind:
case SemIR::BaseDecl::Kind:
case SemIR::FieldDecl::Kind:
case SemIR::ImplDecl::Kind:
case SemIR::Namespace::Kind:
return SemIR::ConstantId::ForTemplateConstant(inst_id);
case SemIR::BoolLiteral::Kind:
case SemIR::FloatLiteral::Kind:
case SemIR::IntValue::Kind:
case SemIR::StringLiteral::Kind:
// Promote literals to the constant block.
// TODO: Convert literals into a canonical form. Currently we can form two
// different `i32` constants with the same value if they are represented
// by `APInt`s with different bit widths.
// TODO: Can the type of an IntValue or FloatLiteral be symbolic? If so,
// we may need to rebuild.
return MakeConstantResult(eval_context.context(), inst, Phase::Template);
// The elements of a constant aggregate can be accessed.
case SemIR::ClassElementAccess::Kind:
case SemIR::StructAccess::Kind:
case SemIR::TupleAccess::Kind:
return PerformAggregateAccess(eval_context, inst);
case CARBON_KIND(SemIR::ImplWitnessAccess access_inst): {
// This is PerformAggregateAccess followed by GetConstantInSpecific.
Phase phase = Phase::Template;
if (ReplaceFieldWithConstantValue(eval_context, &access_inst,
&SemIR::ImplWitnessAccess::witness_id,
&phase)) {
if (auto witness = eval_context.insts().TryGetAs<SemIR::ImplWitness>(
access_inst.witness_id)) {
auto elements = eval_context.inst_blocks().Get(witness->elements_id);
auto index = static_cast<size_t>(access_inst.index.index);
CARBON_CHECK(index < elements.size(), "Access out of bounds.");
// `Phase` is not used here. If this element is a template constant,
// then so is the result of indexing, even if the aggregate also
// contains a symbolic context.
auto element = elements[index];
if (!element.is_valid()) {
// TODO: Perhaps this should be a `{}` value with incomplete type?
CARBON_DIAGNOSTIC(ImplAccessMemberBeforeComplete, Error,
"accessing member from impl before the end of "
"its definition");
// TODO: Add note pointing to the impl declaration.
eval_context.emitter().Emit(eval_context.GetDiagnosticLoc(inst_id),
ImplAccessMemberBeforeComplete);
return SemIR::ErrorInst::SingletonConstantId;
}
LoadImportRef(eval_context.context(), element);
return GetConstantValueInSpecific(eval_context.sem_ir(),
witness->specific_id, element);
} else {
CARBON_CHECK(phase != Phase::Template,
"Failed to evaluate template constant {0} arg0: {1}",
inst, eval_context.insts().Get(access_inst.witness_id));
}
return MakeConstantResult(eval_context.context(), access_inst, phase);
}
return MakeNonConstantResult(phase);
}
case CARBON_KIND(SemIR::ArrayIndex index): {
return PerformArrayIndex(eval_context, index);
}
case CARBON_KIND(SemIR::Call call): {
return MakeConstantForCall(eval_context,
eval_context.GetDiagnosticLoc(inst_id), call);
}
// TODO: These need special handling.
case SemIR::BindValue::Kind:
case SemIR::Deref::Kind:
case SemIR::ImportRefLoaded::Kind:
case SemIR::ReturnSlot::Kind:
case SemIR::Temporary::Kind:
case SemIR::TemporaryStorage::Kind:
case SemIR::ValueAsRef::Kind:
case SemIR::VtablePtr::Kind:
break;
case CARBON_KIND(SemIR::SymbolicBindingPattern bind): {
// TODO: Disable constant evaluation of SymbolicBindingPattern once
// DeduceGenericCallArguments no longer needs implicit params to have
// constant values.
const auto& bind_name =
eval_context.entity_names().Get(bind.entity_name_id);
// If we know which specific we're evaluating within and this is an
// argument of that specific, its constant value is the corresponding
// argument value.
if (auto value =
eval_context.GetCompileTimeBindValue(bind_name.bind_index);
value.is_valid()) {
return value;
}
// The constant form of a symbolic binding is an idealized form of the
// original, with no equivalent value.
bind.entity_name_id =
eval_context.entity_names().MakeCanonical(bind.entity_name_id);
return MakeConstantResult(eval_context.context(), bind, Phase::Symbolic);
}
case CARBON_KIND(SemIR::BindSymbolicName bind): {
const auto& bind_name =
eval_context.entity_names().Get(bind.entity_name_id);
Phase phase;
if (bind_name.name_id == SemIR::NameId::PeriodSelf) {
phase = Phase::PeriodSelfSymbolic;
} else {
// If we know which specific we're evaluating within and this is an
// argument of that specific, its constant value is the corresponding
// argument value.
if (auto value =
eval_context.GetCompileTimeBindValue(bind_name.bind_index);
value.is_valid()) {
return value;
}
phase = Phase::Symbolic;
}
// The constant form of a symbolic binding is an idealized form of the
// original, with no equivalent value.
bind.entity_name_id =
eval_context.entity_names().MakeCanonical(bind.entity_name_id);
bind.value_id = SemIR::InstId::Invalid;
if (!ReplaceFieldWithConstantValue(
eval_context, &bind, &SemIR::BindSymbolicName::type_id, &phase)) {
return MakeNonConstantResult(phase);
}
return MakeConstantResult(eval_context.context(), bind, phase);
}
// These semantic wrappers don't change the constant value.
case CARBON_KIND(SemIR::AsCompatible inst): {
return eval_context.GetConstantValue(inst.source_id);
}
case CARBON_KIND(SemIR::BindAlias typed_inst): {
return eval_context.GetConstantValue(typed_inst.value_id);
}
case CARBON_KIND(SemIR::ExportDecl typed_inst): {
return eval_context.GetConstantValue(typed_inst.value_id);
}
case CARBON_KIND(SemIR::NameRef typed_inst): {
return eval_context.GetConstantValue(typed_inst.value_id);
}
case CARBON_KIND(SemIR::ValueParamPattern param_pattern): {
// TODO: Treat this as a non-expression (here and in GetExprCategory)
// once generic deduction doesn't need patterns to have constant values.
return eval_context.GetConstantValue(param_pattern.subpattern_id);
}
case CARBON_KIND(SemIR::Converted typed_inst): {
return eval_context.GetConstantValue(typed_inst.result_id);
}
case CARBON_KIND(SemIR::InitializeFrom typed_inst): {
return eval_context.GetConstantValue(typed_inst.src_id);
}
case CARBON_KIND(SemIR::SpliceBlock typed_inst): {
return eval_context.GetConstantValue(typed_inst.result_id);
}
case CARBON_KIND(SemIR::ValueOfInitializer typed_inst): {
return eval_context.GetConstantValue(typed_inst.init_id);
}
case CARBON_KIND(SemIR::FacetAccessType typed_inst): {
Phase phase = Phase::Template;
if (ReplaceFieldWithConstantValue(
eval_context, &typed_inst,
&SemIR::FacetAccessType::facet_value_inst_id, &phase)) {
if (auto facet_value = eval_context.insts().TryGetAs<SemIR::FacetValue>(
typed_inst.facet_value_inst_id)) {
return eval_context.constant_values().Get(facet_value->type_inst_id);
}
return MakeConstantResult(eval_context.context(), typed_inst, phase);
} else {
return MakeNonConstantResult(phase);
}
}
case CARBON_KIND(SemIR::FacetAccessWitness typed_inst): {
Phase phase = Phase::Template;
if (ReplaceFieldWithConstantValue(
eval_context, &typed_inst,
&SemIR::FacetAccessWitness::facet_value_inst_id, &phase)) {
if (auto facet_value = eval_context.insts().TryGetAs<SemIR::FacetValue>(
typed_inst.facet_value_inst_id)) {
return eval_context.constant_values().Get(
facet_value->witness_inst_id);
}
return MakeConstantResult(eval_context.context(), typed_inst, phase);
} else {
return MakeNonConstantResult(phase);
}
}
case CARBON_KIND(SemIR::WhereExpr typed_inst): {
Phase phase = Phase::Template;
SemIR::TypeId base_facet_type_id =
eval_context.insts().Get(typed_inst.period_self_id).type_id();
SemIR::Inst base_facet_inst =
eval_context.GetConstantValueAsInst(base_facet_type_id);
SemIR::FacetTypeInfo info = {.other_requirements = false};
// `where` provides that the base facet is an error, `type`, or a facet
// type.
if (auto facet_type = base_facet_inst.TryAs<SemIR::FacetType>()) {
info = GetConstantFacetTypeInfo(eval_context, facet_type->facet_type_id,
&phase);
} else if (base_facet_type_id == SemIR::ErrorInst::SingletonTypeId) {
return SemIR::ErrorInst::SingletonConstantId;
} else {
CARBON_CHECK(base_facet_type_id == SemIR::TypeType::SingletonTypeId,
"Unexpected type_id: {0}, inst: {1}", base_facet_type_id,
base_facet_inst);
}
if (typed_inst.requirements_id.is_valid()) {
auto insts = eval_context.inst_blocks().Get(typed_inst.requirements_id);
for (auto inst_id : insts) {
if (auto rewrite =
eval_context.insts().TryGetAs<SemIR::RequirementRewrite>(
inst_id)) {
SemIR::ConstantId lhs =
eval_context.GetConstantValue(rewrite->lhs_id);
SemIR::ConstantId rhs =
eval_context.GetConstantValue(rewrite->rhs_id);
// `where` requirements using `.Self` should not be considered
// symbolic
UpdatePhaseIgnorePeriodSelf(eval_context, lhs, &phase);
UpdatePhaseIgnorePeriodSelf(eval_context, rhs, &phase);
info.rewrite_constraints.push_back(
{.lhs_const_id = lhs, .rhs_const_id = rhs});
} else {
// TODO: Handle other requirements
info.other_requirements = true;
}
}
}
info.Canonicalize();
return MakeFacetTypeResult(eval_context.context(), info, phase);
}
// `not true` -> `false`, `not false` -> `true`.
// All other uses of unary `not` are non-constant.
case CARBON_KIND(SemIR::UnaryOperatorNot typed_inst): {
auto const_id = eval_context.GetConstantValue(typed_inst.operand_id);
auto phase = GetPhase(eval_context, const_id);
if (phase == Phase::Template) {
auto value = eval_context.insts().GetAs<SemIR::BoolLiteral>(
eval_context.constant_values().GetInstId(const_id));
return MakeBoolResult(eval_context.context(), value.type_id,
!value.value.ToBool());
}
if (phase == Phase::UnknownDueToError) {
return SemIR::ErrorInst::SingletonConstantId;
}
break;
}
// `const (const T)` evaluates to `const T`. Otherwise, `const T` evaluates
// to itself.
case CARBON_KIND(SemIR::ConstType typed_inst): {
auto phase = Phase::Template;
auto inner_id =
GetConstantValue(eval_context, typed_inst.inner_id, &phase);
if (eval_context.context().types().Is<SemIR::ConstType>(inner_id)) {
return eval_context.context().types().GetConstantId(inner_id);
}
typed_inst.inner_id = inner_id;
return MakeConstantResult(eval_context.context(), typed_inst, phase);
}
case CARBON_KIND(SemIR::RequireCompleteType require_complete): {
auto phase = Phase::Template;
auto witness_type_id = eval_context.context().GetSingletonType(
SemIR::WitnessType::SingletonInstId);
auto complete_type_id = GetConstantValue(
eval_context, require_complete.complete_type_id, &phase);
// If the type is a template constant, require it to be complete now.
if (phase == Phase::Template) {
if (!eval_context.context().TryToCompleteType(
complete_type_id, eval_context.GetDiagnosticLoc(inst_id), [&] {
CARBON_DIAGNOSTIC(IncompleteTypeInMonomorphization, Error,
"{0} evaluates to incomplete type {1}",
SemIR::TypeId, SemIR::TypeId);
return eval_context.emitter().Build(
eval_context.GetDiagnosticLoc(inst_id),
IncompleteTypeInMonomorphization,
require_complete.complete_type_id, complete_type_id);
})) {
return SemIR::ErrorInst::SingletonConstantId;
}
return MakeConstantResult(
eval_context.context(),
SemIR::CompleteTypeWitness{
.type_id = witness_type_id,
.object_repr_id =
eval_context.types().GetObjectRepr(complete_type_id)},
phase);
}
// If it's not a template constant, require it to be complete once it
// becomes one.
return MakeConstantResult(
eval_context.context(),
SemIR::RequireCompleteType{.type_id = witness_type_id,
.complete_type_id = complete_type_id},
phase);
}
// These cases are either not expressions or not constant.
case SemIR::AddrPattern::Kind:
case SemIR::Assign::Kind:
case SemIR::BindName::Kind:
case SemIR::BindingPattern::Kind:
case SemIR::BlockArg::Kind:
case SemIR::Branch::Kind:
case SemIR::BranchIf::Kind:
case SemIR::BranchWithArg::Kind:
case SemIR::ImportDecl::Kind:
case SemIR::NameBindingDecl::Kind:
case SemIR::OutParam::Kind:
case SemIR::OutParamPattern::Kind:
case SemIR::RequirementEquivalent::Kind:
case SemIR::RequirementImpls::Kind:
case SemIR::RequirementRewrite::Kind:
case SemIR::Return::Kind:
case SemIR::ReturnExpr::Kind:
case SemIR::ReturnSlotPattern::Kind:
case SemIR::StructLiteral::Kind:
case SemIR::TupleLiteral::Kind:
case SemIR::ValueParam::Kind:
case SemIR::VarPattern::Kind:
case SemIR::VarStorage::Kind:
break;
case SemIR::ImportRefUnloaded::Kind:
CARBON_FATAL("ImportRefUnloaded should be loaded before TryEvalInst: {0}",
inst);
}
return SemIR::ConstantId::NotConstant;
}
auto TryEvalInst(Context& context, SemIR::InstId inst_id, SemIR::Inst inst)
-> SemIR::ConstantId {
EvalContext eval_context(context, inst_id);
return TryEvalInstInContext(eval_context, inst_id, inst);
}
auto TryEvalBlockForSpecific(Context& context, SemIRLoc loc,
SemIR::SpecificId specific_id,
SemIR::GenericInstIndex::Region region)
-> SemIR::InstBlockId {
auto generic_id = context.specifics().Get(specific_id).generic_id;
auto eval_block_id = context.generics().Get(generic_id).GetEvalBlock(region);
auto eval_block = context.inst_blocks().Get(eval_block_id);
llvm::SmallVector<SemIR::InstId> result;
result.resize(eval_block.size(), SemIR::InstId::Invalid);
EvalContext eval_context(context, loc, specific_id,
SpecificEvalInfo{
.region = region,
.values = result,
});
DiagnosticAnnotationScope annotate_diagnostics(
&context.emitter(), [&](auto& builder) {
CARBON_DIAGNOSTIC(ResolvingSpecificHere, Note, "in {0} used here",
InstIdAsType);
if (loc.is_inst_id && !loc.inst_id.is_valid()) {
return;
}
builder.Note(loc, ResolvingSpecificHere,
GetInstForSpecific(context, specific_id));
});
for (auto [i, inst_id] : llvm::enumerate(eval_block)) {
auto const_id = TryEvalInstInContext(eval_context, inst_id,
context.insts().Get(inst_id));
result[i] = context.constant_values().GetInstId(const_id);
CARBON_CHECK(result[i].is_valid());
}
return context.inst_blocks().Add(result);
}
} // namespace Carbon::Check
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