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Refactor StringifyTypeExpr (#4597)

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* Make the step stack into a class
* Make the operations on the stack (pushing, popping, test for done)
into methods on the stack class.
* Add more kinds of steps (array bound and name).
* Rewrite cases to use the new kinds of steps. Afterward, none use
`Step::Next()` or the step index, so those get removed.
* Add another convenience method `PushTypeId`.
* Remove the `SemIR::File&` member from the steps, since it doesn't
change.

Hopefully using `step_stack.Push`... calls makes it clear that they are
resolved in the reverse order they are executed.

---------

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
This commit is contained in:
josh11b
2024-11-27 02:20:31 +00:00
committed by GitHub
co-authored by Josh L
parent 14bb9dd5cf
commit b894d4e62c
1 changed files with 148 additions and 130 deletions
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toolchain/sem_ir/stringify_type.cpp
+148 -130
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@@ -24,18 +24,16 @@ static auto GetTypePrecedence(InstKind kind) -> int {
return 0;
}
auto StringifyTypeExpr(const SemIR::File& outer_sem_ir, InstId outer_inst_id)
-> std::string {
std::string str;
llvm::raw_string_ostream out(str);
namespace {
class StepStack {
public:
enum Kind : uint8_t {
Inst,
FixedString,
ArrayBound,
Name,
};
struct Step {
// The instruction's file.
const File& sem_ir;
enum Kind : uint8_t {
Inst,
FixedString,
};
// The kind of step to perform.
Kind kind;
union {
@@ -43,79 +41,100 @@ auto StringifyTypeExpr(const SemIR::File& outer_sem_ir, InstId outer_inst_id)
InstId inst_id;
// The fixed string to print, when kind is FixedString.
const char* fixed_string;
// The array bound to print, when kind is ArrayBound.
InstId bound_id;
// The name to print, when kind is Name.
NameId name_id;
};
// The index within the current step. Not used by all kinds of step.
int index = 0;
};
auto Next() const -> Step {
Step next = *this;
++next.index;
return next;
explicit StepStack(const SemIR::File* file, InstId outer_inst_id)
: sem_ir(file) {
steps.push_back({.kind = Inst, .inst_id = outer_inst_id});
}
auto PushInstId(InstId inst_id) -> void {
steps.push_back({.kind = Inst, .inst_id = inst_id});
}
auto PushString(const char* string) -> void {
steps.push_back({.kind = FixedString, .fixed_string = string});
}
auto PushArrayBound(InstId bound_id) -> void {
steps.push_back({.kind = ArrayBound, .bound_id = bound_id});
}
auto PushNameId(NameId name_id) -> void {
steps.push_back({.kind = Name, .name_id = name_id});
}
auto PushTypeId(TypeId type_id) -> void {
PushInstId(sem_ir->types().GetInstId(type_id));
}
auto PushSpecificId(const EntityWithParamsBase& entity,
SpecificId specific_id) -> void {
if (!entity.param_patterns_id.is_valid()) {
return;
}
};
llvm::SmallVector<Step> steps = {Step{
.sem_ir = outer_sem_ir, .kind = Step::Inst, .inst_id = outer_inst_id}};
int num_params = sem_ir->inst_blocks().Get(entity.param_patterns_id).size();
if (!num_params) {
PushString("()");
return;
}
if (!specific_id.is_valid()) {
// The name of the generic was used within the generic itself.
// TODO: Should we print the names of the generic parameters in this
// case?
return;
}
const auto& specific = sem_ir->specifics().Get(specific_id);
auto args =
sem_ir->inst_blocks().Get(specific.args_id).take_back(num_params);
bool last = true;
for (auto arg : llvm::reverse(args)) {
PushString(last ? ")" : ", ");
PushInstId(arg);
last = false;
}
PushString("(");
}
// Note: The `steps` worklist is a stack and so work is resolved in the
// reverse order from the order added.
auto push_string = [&](const char* string) {
steps.push_back({.sem_ir = outer_sem_ir,
.kind = Step::FixedString,
.fixed_string = string});
};
auto empty() const -> bool { return steps.empty(); }
auto Pop() -> Step { return steps.pop_back_val(); }
while (!steps.empty()) {
auto step = steps.pop_back_val();
private:
const SemIR::File* sem_ir;
llvm::SmallVector<Step> steps;
};
} // namespace
if (step.kind == Step::FixedString) {
auto StringifyTypeExpr(const SemIR::File& sem_ir, InstId outer_inst_id)
-> std::string {
std::string str;
llvm::raw_string_ostream out(str);
// Note: Since this is a stack, work is resolved in the reverse order from the
// order pushed.
StepStack step_stack(&sem_ir, outer_inst_id);
while (!step_stack.empty()) {
auto step = step_stack.Pop();
if (step.kind == StepStack::FixedString) {
out << step.fixed_string;
continue;
}
CARBON_CHECK(step.kind == Step::Inst);
if (step.kind == StepStack::ArrayBound) {
out << sem_ir.GetArrayBoundValue(step.bound_id);
continue;
}
if (step.kind == StepStack::Name) {
out << sem_ir.names().GetFormatted(step.name_id);
continue;
}
CARBON_CHECK(step.kind == StepStack::Inst);
if (!step.inst_id.is_valid()) {
out << "<invalid type>";
continue;
}
const auto& sem_ir = step.sem_ir;
// Helper for instructions with the current sem_ir.
// Note: The `steps` worklist is a stack and so work is resolved in the
// reverse order from the order added.
auto push_inst_id = [&](InstId inst_id) {
steps.push_back(
{.sem_ir = sem_ir, .kind = Step::Inst, .inst_id = inst_id});
};
auto push_specific_id = [&](const EntityWithParamsBase& entity,
SpecificId specific_id) {
if (!entity.param_patterns_id.is_valid()) {
return;
}
int num_params =
sem_ir.inst_blocks().Get(entity.param_patterns_id).size();
if (!num_params) {
out << "()";
return;
}
if (!specific_id.is_valid()) {
// The name of the generic was used within the generic itself.
// TODO: Should we print the names of the generic parameters in this
// case?
return;
}
out << "(";
const auto& specific = sem_ir.specifics().Get(specific_id);
auto args =
sem_ir.inst_blocks().Get(specific.args_id).take_back(num_params);
bool last = true;
for (auto arg : llvm::reverse(args)) {
push_string(last ? ")" : ", ");
push_inst_id(arg);
last = false;
}
};
auto untyped_inst = sem_ir.insts().Get(step.inst_id);
CARBON_KIND_SWITCH(untyped_inst) {
case SemIR::AutoType::Kind:
@@ -135,21 +154,19 @@ auto StringifyTypeExpr(const SemIR::File& outer_sem_ir, InstId outer_inst_id)
break;
}
case CARBON_KIND(ArrayType inst): {
if (step.index == 0) {
out << "[";
steps.push_back(step.Next());
push_inst_id(sem_ir.types().GetInstId(inst.element_type_id));
} else if (step.index == 1) {
out << "; " << sem_ir.GetArrayBoundValue(inst.bound_id) << "]";
}
out << "[";
step_stack.PushString("]");
step_stack.PushArrayBound(inst.bound_id);
step_stack.PushString("; ");
step_stack.PushTypeId(inst.element_type_id);
break;
}
case CARBON_KIND(AssociatedEntityType inst): {
out << "<associated ";
push_string(">");
push_inst_id(sem_ir.types().GetInstId(inst.interface_type_id));
push_string(" in ");
push_inst_id(sem_ir.types().GetInstId(inst.entity_type_id));
step_stack.PushString(">");
step_stack.PushTypeId(inst.interface_type_id);
step_stack.PushString(" in ");
step_stack.PushTypeId(inst.entity_type_id);
break;
}
case BindAlias::Kind:
@@ -164,7 +181,7 @@ auto StringifyTypeExpr(const SemIR::File& outer_sem_ir, InstId outer_inst_id)
case CARBON_KIND(ClassType inst): {
const auto& class_info = sem_ir.classes().Get(inst.class_id);
out << sem_ir.names().GetFormatted(class_info.name_id);
push_specific_id(class_info, inst.specific_id);
step_stack.PushSpecificId(class_info, inst.specific_id);
break;
}
case CARBON_KIND(ConstType inst): {
@@ -175,53 +192,53 @@ auto StringifyTypeExpr(const SemIR::File& outer_sem_ir, InstId outer_inst_id)
if (GetTypePrecedence(sem_ir.insts().Get(inner_type_inst_id).kind()) <
GetTypePrecedence(SemIR::ConstType::Kind)) {
out << "(";
push_string(")");
step_stack.PushString(")");
}
push_inst_id(inner_type_inst_id);
step_stack.PushInstId(inner_type_inst_id);
break;
}
case CARBON_KIND(FacetAccessType inst): {
// Given `T:! I`, print `T as type` as simply `T`.
push_inst_id(inst.facet_value_inst_id);
step_stack.PushInstId(inst.facet_value_inst_id);
break;
}
case CARBON_KIND(FacetAccessWitness inst): {
out << "<witness for ";
push_string(">");
push_inst_id(inst.facet_value_inst_id);
step_stack.PushString(">");
step_stack.PushInstId(inst.facet_value_inst_id);
break;
}
case CARBON_KIND(FacetType inst): {
const FacetTypeInfo& facet_type_info =
sem_ir.facet_types().Get(inst.facet_type_id);
// TODO: Also output other restrictions from facet_type_info.
if (facet_type_info.requirement_block_id.is_valid()) {
step_stack.PushString(" where...");
}
if (facet_type_info.impls_constraints.empty()) {
out << "type";
} else {
const auto& impls = facet_type_info.impls_constraints[step.index];
step_stack.PushString("type");
break;
}
for (auto index : llvm::reverse(
llvm::seq(facet_type_info.impls_constraints.size()))) {
const auto& impls = facet_type_info.impls_constraints[index];
const auto& interface_info =
sem_ir.interfaces().Get(impls.interface_id);
out << sem_ir.names().GetFormatted(interface_info.name_id);
push_specific_id(interface_info, impls.specific_id);
if (step.index + 1 <
static_cast<int>(facet_type_info.impls_constraints.size())) {
steps.push_back(step.Next());
push_string(" & ");
step_stack.PushSpecificId(interface_info, impls.specific_id);
step_stack.PushNameId(interface_info.name_id);
if (index > 0) {
step_stack.PushString(" & ");
}
}
// TODO: Also output other restrictions from facet_type_info.
if (step.index + 1 >=
static_cast<int>(facet_type_info.impls_constraints.size()) &&
facet_type_info.requirement_block_id.is_valid()) {
out << " where...";
}
break;
}
case CARBON_KIND(FacetValue inst): {
// No need to output the witness.
push_inst_id(sem_ir.types().GetInstId(inst.type_id));
push_string(" as ");
push_inst_id(inst.type_inst_id);
step_stack.PushTypeId(inst.type_id);
step_stack.PushString(" as ");
step_stack.PushInstId(inst.type_inst_id);
break;
}
case CARBON_KIND(FloatType inst): {
@@ -232,8 +249,8 @@ auto StringifyTypeExpr(const SemIR::File& outer_sem_ir, InstId outer_inst_id)
sem_ir.ints().Get(width_value->int_id).print(out, /*isSigned=*/false);
} else {
out << "Core.Float(";
push_string(")");
push_inst_id(inst.bit_width_id);
step_stack.PushString(")");
step_stack.PushInstId(inst.bit_width_id);
}
break;
}
@@ -261,8 +278,8 @@ auto StringifyTypeExpr(const SemIR::File& outer_sem_ir, InstId outer_inst_id)
sem_ir.ints().Get(width_value->int_id).print(out, /*isSigned=*/false);
} else {
out << (inst.int_kind.is_signed() ? "Core.Int(" : "Core.UInt(");
push_string(")");
push_inst_id(inst.bit_width_id);
step_stack.PushString(")");
step_stack.PushInstId(inst.bit_width_id);
}
break;
}
@@ -271,8 +288,8 @@ auto StringifyTypeExpr(const SemIR::File& outer_sem_ir, InstId outer_inst_id)
break;
}
case CARBON_KIND(PointerType inst): {
push_string("*");
push_inst_id(sem_ir.types().GetInstId(inst.pointee_id));
step_stack.PushString("*");
step_stack.PushTypeId(inst.pointee_id);
break;
}
case CARBON_KIND(StructType inst): {
@@ -281,17 +298,18 @@ auto StringifyTypeExpr(const SemIR::File& outer_sem_ir, InstId outer_inst_id)
out << "{}";
break;
}
if (step.index >= static_cast<int>(fields.size())) {
out << "}";
break;
out << "{";
step_stack.PushString("}");
for (auto index : llvm::reverse(llvm::seq(fields.size()))) {
const auto& field = fields[index];
step_stack.PushTypeId(field.type_id);
step_stack.PushString(": ");
step_stack.PushNameId(field.name_id);
step_stack.PushString(".");
if (index > 0) {
step_stack.PushString(", ");
}
}
const auto& field = fields[step.index];
out << (step.index == 0 ? "{" : ", ") << "."
<< sem_ir.names().GetFormatted(field.name_id) << ": ";
steps.push_back(step.Next());
push_inst_id(sem_ir.types().GetInstId(field.type_id));
break;
}
case CARBON_KIND(TupleType inst): {
@@ -301,31 +319,31 @@ auto StringifyTypeExpr(const SemIR::File& outer_sem_ir, InstId outer_inst_id)
break;
}
out << "(";
push_string(")");
step_stack.PushString(")");
// A tuple of one element has a comma to disambiguate from an
// expression.
if (refs.size() == 1) {
push_string(",");
step_stack.PushString(",");
}
for (auto i : llvm::reverse(llvm::seq(refs.size()))) {
push_inst_id(sem_ir.types().GetInstId(refs[i]));
step_stack.PushTypeId(refs[i]);
if (i > 0) {
push_string(", ");
step_stack.PushString(", ");
}
}
break;
}
case CARBON_KIND(UnboundElementType inst): {
out << "<unbound element of class ";
push_string(">");
push_inst_id(sem_ir.types().GetInstId(inst.class_type_id));
step_stack.PushString(">");
step_stack.PushTypeId(inst.class_type_id);
break;
}
case CARBON_KIND(WhereExpr inst): {
out << "<where restriction on ";
push_string(">");
step_stack.PushString(">");
TypeId type_id = sem_ir.insts().Get(inst.period_self_id).type_id();
push_inst_id(sem_ir.types().GetInstId(type_id));
step_stack.PushTypeId(type_id);
// TODO: Also output restrictions from the inst block
// inst.requirements_id.
break;
@@ -404,7 +422,7 @@ auto StringifyTypeExpr(const SemIR::File& outer_sem_ir, InstId outer_inst_id)
auto const_inst_id =
sem_ir.constant_values().GetConstantInstId(step.inst_id);
if (const_inst_id.is_valid() && const_inst_id != step.inst_id) {
push_inst_id(const_inst_id);
step_stack.PushInstId(const_inst_id);
break;
}