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a5df8ad736d1e02c1756e662ff908fead94982bb
carbon-lang/toolchain/sem_ir/file.cpp
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Jon Ross-Perkins a5df8ad736 Support destruction of storage (#5171) 
What this does:

- Adds tracking where storage is allocated.
- Determines if that storage supports destruction and, if so, records
the `destroy` function for it.
- Calls any found `destroy` functions when going out-of-scope.

What this does not do:

- Precise scope tracking of temporaries. We currently don't define
temporary scopes, which would probably be the solution.
- Destruction for anything but a `class` with `fn destroy`, in an
implicit return. That excludes:
- Classes with members that need destruction, particularly in the
absence of `fn destroy`.
  - Structs, tuples, and arrays.
  - Explicit returns, break, continue, nested scopes.

Noting the exclusions in particular, I think those will need work to
support, but this should set the right framework.

The cleanup block concept stems from clang and trying to share code
across cleanups, from discussion with chandlerc. Note in this
implementation I try to find `destroy` functions early on: that's so
that, when destruction is present on multiple paths, particularly
non-shared paths, we only bind the `destroy` method once.

Implementation-wise, I'll note this adds a `has_cleanup` flag to
`TemporaryStorage` and `VarStorage`. There are several related options,
but this felt similar to other information we're trying to track on
instructions. My goal with this is to mitigate the chance of accidental
calls where the storage may not be tracked for destruction. Alternatives
I considered were to not add the flag (I was worried about heightened
risk of errors), or to just add a concept for the relevant `requires`
(which just felt inconsistent).

Cleanup logic ends up in control_flow in this change because I thought
it was a reasonably consistent place for the cleanup block concept and
its pretty direct control flow interactions.
2025-03-28 00:29:17 +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/sem_ir/file.h"
#include "common/check.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "toolchain/base/kind_switch.h"
#include "toolchain/base/shared_value_stores.h"
#include "toolchain/base/yaml.h"
#include "toolchain/parse/node_ids.h"
#include "toolchain/sem_ir/ids.h"
#include "toolchain/sem_ir/inst.h"
#include "toolchain/sem_ir/inst_kind.h"
#include "toolchain/sem_ir/typed_insts.h"
namespace Carbon::SemIR {
File::File(const Parse::Tree* parse_tree, CheckIRId check_ir_id,
const std::optional<Parse::Tree::PackagingDecl>& packaging_decl,
SharedValueStores& value_stores, std::string filename)
: parse_tree_(parse_tree),
check_ir_id_(check_ir_id),
package_id_(packaging_decl ? packaging_decl->names.package_id
: PackageNameId::None),
library_id_(packaging_decl ? LibraryNameId::ForStringLiteralValueId(
packaging_decl->names.library_id)
: LibraryNameId::Default),
value_stores_(&value_stores),
filename_(std::move(filename)),
impls_(*this),
type_blocks_(allocator_),
constant_values_(ConstantId::NotConstant),
inst_blocks_(allocator_),
constants_(this) {
// `type` and the error type are both complete & concrete types.
types_.SetComplete(TypeType::SingletonTypeId,
{.value_repr = {.kind = ValueRepr::Copy,
.type_id = TypeType::SingletonTypeId}});
types_.SetComplete(ErrorInst::SingletonTypeId,
{.value_repr = {.kind = ValueRepr::Copy,
.type_id = ErrorInst::SingletonTypeId}});
insts_.Reserve(SingletonInstKinds.size());
for (auto kind : SingletonInstKinds) {
auto inst_id =
insts_.AddInNoBlock(LocIdAndInst::NoLoc(Inst::MakeSingleton(kind)));
constant_values_.Set(inst_id,
SemIR::ConstantId::ForConcreteConstant(inst_id));
}
}
auto File::Verify() const -> ErrorOr<Success> {
// Invariants don't necessarily hold for invalid IR.
if (has_errors_) {
return Success();
}
// Check that every code block has a terminator sequence that appears at the
// end of the block.
for (const Function& function : functions_.array_ref()) {
for (InstBlockId block_id : function.body_block_ids) {
TerminatorKind prior_kind = TerminatorKind::NotTerminator;
for (InstId inst_id : inst_blocks().Get(block_id)) {
TerminatorKind inst_kind =
insts().Get(inst_id).kind().terminator_kind();
if (prior_kind == TerminatorKind::Terminator) {
return Error(llvm::formatv("Inst {0} in block {1} follows terminator",
inst_id, block_id));
}
if (prior_kind > inst_kind) {
return Error(
llvm::formatv("Non-terminator inst {0} in block {1} follows "
"terminator sequence",
inst_id, block_id));
}
prior_kind = inst_kind;
}
if (prior_kind != TerminatorKind::Terminator) {
return Error(llvm::formatv("No terminator in block {0}", block_id));
}
}
}
// TODO: Check that an instruction only references other instructions that are
// either global or that dominate it.
return Success();
}
auto File::OutputYaml(bool include_singletons) const -> Yaml::OutputMapping {
return Yaml::OutputMapping([this, include_singletons](
Yaml::OutputMapping::Map map) {
map.Add("filename", filename_);
map.Add(
"sem_ir", Yaml::OutputMapping([&](Yaml::OutputMapping::Map map) {
map.Add("import_irs", import_irs_.OutputYaml());
map.Add("import_ir_insts", import_ir_insts_.OutputYaml());
map.Add("name_scopes", name_scopes_.OutputYaml());
map.Add("entity_names", entity_names_.OutputYaml());
map.Add("functions", functions_.OutputYaml());
map.Add("classes", classes_.OutputYaml());
map.Add("generics", generics_.OutputYaml());
map.Add("specifics", specifics_.OutputYaml());
map.Add("struct_type_fields", struct_type_fields_.OutputYaml());
map.Add("types", types_.OutputYaml());
map.Add("type_blocks", type_blocks_.OutputYaml());
map.Add("insts",
Yaml::OutputMapping([&](Yaml::OutputMapping::Map map) {
for (auto [id, inst] : insts_.enumerate()) {
if (!include_singletons && IsSingletonInstId(id)) {
continue;
}
map.Add(PrintToString(id), Yaml::OutputScalar(inst));
}
}));
map.Add("constant_values",
Yaml::OutputMapping([&](Yaml::OutputMapping::Map map) {
for (auto [id, _] : insts_.enumerate()) {
if (!include_singletons && IsSingletonInstId(id)) {
continue;
}
auto value = constant_values_.Get(id);
if (!value.has_value() || value.is_constant()) {
map.Add(PrintToString(id), Yaml::OutputScalar(value));
}
}
}));
map.Add(
"symbolic_constants",
Yaml::OutputMapping([&](Yaml::OutputMapping::Map map) {
for (const auto& [i, symbolic] :
llvm::enumerate(constant_values().symbolic_constants())) {
map.Add(
PrintToString(ConstantId::ForSymbolicConstantIndex(i)),
Yaml::OutputScalar(symbolic));
}
}));
map.Add("inst_blocks", inst_blocks_.OutputYaml());
}));
});
}
auto File::CollectMemUsage(MemUsage& mem_usage, llvm::StringRef label) const
-> void {
mem_usage.Collect(MemUsage::ConcatLabel(label, "allocator_"), allocator_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "entity_names_"),
entity_names_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "functions_"), functions_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "classes_"), classes_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "interfaces_"), interfaces_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "impls_"), impls_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "generics_"), generics_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "specifics_"), specifics_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "import_irs_"), import_irs_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "import_ir_insts_"),
import_ir_insts_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "struct_type_fields_"),
struct_type_fields_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "type_blocks_"), type_blocks_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "insts_"), insts_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "name_scopes_"), name_scopes_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "constant_values_"),
constant_values_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "inst_blocks_"), inst_blocks_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "constants_"), constants_);
mem_usage.Collect(MemUsage::ConcatLabel(label, "types_"), types_);
}
auto GetExprCategory(const File& file, InstId inst_id) -> ExprCategory {
const File* ir = &file;
// The overall expression category if the current instruction is a value
// expression.
ExprCategory value_category = ExprCategory::Value;
while (true) {
auto untyped_inst = ir->insts().Get(inst_id);
CARBON_KIND_SWITCH(untyped_inst) {
case AdaptDecl::Kind:
case AddrPattern::Kind:
case Assign::Kind:
case BaseDecl::Kind:
case BindingPattern::Kind:
case Branch::Kind:
case BranchIf::Kind:
case BranchWithArg::Kind:
case FieldDecl::Kind:
case FunctionDecl::Kind:
case ImplDecl::Kind:
case NameBindingDecl::Kind:
case Namespace::Kind:
case OutParamPattern::Kind:
case RefParamPattern::Kind:
case RequirementEquivalent::Kind:
case RequirementImpls::Kind:
case RequirementRewrite::Kind:
case Return::Kind:
case ReturnSlotPattern::Kind:
case ReturnExpr::Kind:
case TuplePattern::Kind:
case VarPattern::Kind:
case Vtable::Kind:
return ExprCategory::NotExpr;
case ImportRefUnloaded::Kind:
case ImportRefLoaded::Kind: {
auto import_ir_inst = ir->import_ir_insts().Get(
untyped_inst.As<SemIR::AnyImportRef>().import_ir_inst_id);
ir = ir->import_irs().Get(import_ir_inst.ir_id).sem_ir;
inst_id = import_ir_inst.inst_id;
continue;
}
case CARBON_KIND(AsCompatible inst): {
inst_id = inst.source_id;
continue;
}
case CARBON_KIND(BindAlias inst): {
inst_id = inst.value_id;
continue;
}
case CARBON_KIND(ExportDecl inst): {
inst_id = inst.value_id;
continue;
}
case CARBON_KIND(NameRef inst): {
inst_id = inst.value_id;
continue;
}
case CARBON_KIND(Converted inst): {
inst_id = inst.result_id;
continue;
}
case CARBON_KIND(SpecificConstant inst): {
inst_id = inst.inst_id;
continue;
}
case AccessMemberAction::Kind:
case AccessOptionalMemberAction::Kind:
case AddrOf::Kind:
case ArrayType::Kind:
case AssociatedConstantDecl::Kind:
case AssociatedEntity::Kind:
case AssociatedEntityType::Kind:
case AutoType::Kind:
case BindSymbolicName::Kind:
case BindValue::Kind:
case BlockArg::Kind:
case BoolLiteral::Kind:
case BoolType::Kind:
case BoundMethod::Kind:
case BoundMethodType::Kind:
case ClassDecl::Kind:
case ClassType::Kind:
case CompleteTypeWitness::Kind:
case ConstType::Kind:
case ConvertToValueAction::Kind:
case FacetAccessType::Kind:
case FacetAccessWitness::Kind:
case FacetType::Kind:
case FacetValue::Kind:
case FloatLiteral::Kind:
case FloatType::Kind:
case FunctionType::Kind:
case FunctionTypeWithSelfType::Kind:
case GenericClassType::Kind:
case GenericInterfaceType::Kind:
case LookupImplWitness::Kind:
case ImplWitness::Kind:
case ImplWitnessAccess::Kind:
case ImportCppDecl::Kind:
case ImportDecl::Kind:
case InstType::Kind:
case InstValue::Kind:
case IntLiteralType::Kind:
case IntType::Kind:
case IntValue::Kind:
case InterfaceDecl::Kind:
case LegacyFloatType::Kind:
case NamespaceType::Kind:
case PointerType::Kind:
case RefineTypeAction::Kind:
case RequireCompleteType::Kind:
case SpecificFunction::Kind:
case SpecificFunctionType::Kind:
case SpecificImplFunction::Kind:
case StringLiteral::Kind:
case StringType::Kind:
case StructType::Kind:
case StructValue::Kind:
case SymbolicBindingPattern::Kind:
case TupleType::Kind:
case TupleValue::Kind:
case TypeOfInst::Kind:
case TypeType::Kind:
case UnaryOperatorNot::Kind:
case UnboundElementType::Kind:
case ValueOfInitializer::Kind:
case ValueParam::Kind:
case ValueParamPattern::Kind:
case VtableType::Kind:
case WhereExpr::Kind:
case WitnessType::Kind:
return value_category;
case ErrorInst::Kind:
return ExprCategory::Error;
case CARBON_KIND(BindName inst): {
// TODO: Don't rely on value_id for expression category, since it may
// not be valid yet. This workaround only works because we don't support
// `var` in function signatures yet.
if (!inst.value_id.has_value()) {
return value_category;
}
inst_id = inst.value_id;
continue;
}
case CARBON_KIND(ArrayIndex inst): {
inst_id = inst.array_id;
continue;
}
case VtablePtr::Kind:
return ExprCategory::EphemeralRef;
case CARBON_KIND(ClassElementAccess inst): {
inst_id = inst.base_id;
// A value of class type is a pointer to an object representation.
// Therefore, if the base is a value, the result is an ephemeral
// reference.
value_category = ExprCategory::EphemeralRef;
continue;
}
case CARBON_KIND(StructAccess inst): {
inst_id = inst.struct_id;
continue;
}
case CARBON_KIND(TupleAccess inst): {
inst_id = inst.tuple_id;
continue;
}
case CARBON_KIND(SpliceBlock inst): {
inst_id = inst.result_id;
continue;
}
case SpliceInst::Kind:
// TODO: Add ExprCategory::Dependent.
return value_category;
case StructLiteral::Kind:
case TupleLiteral::Kind:
return ExprCategory::Mixed;
case ArrayInit::Kind:
case Call::Kind:
case InitializeFrom::Kind:
case ClassInit::Kind:
case StructInit::Kind:
case TupleInit::Kind:
return ExprCategory::Initializing;
case Deref::Kind:
case VarStorage::Kind:
case ReturnSlot::Kind:
return ExprCategory::DurableRef;
case Temporary::Kind:
case TemporaryStorage::Kind:
case ValueAsRef::Kind:
return ExprCategory::EphemeralRef;
case OutParam::Kind:
case RefParam::Kind:
// TODO: Consider introducing a separate category for OutParam:
// unlike other DurableRefs, it permits initialization.
return ExprCategory::DurableRef;
}
}
}
} // namespace Carbon::SemIR
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