mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-24 21:50:14 +01:00
Jon Ross-Perkins
2c6d9c7f66
Discussed briefly [on Discord](https://discord.com/channels/655572317891461132/655578254970716160/1470442830118912265), done to reduce confusion. Assisted-by: Google Antigravity with Gemini 3 Flash
97 lines
4.0 KiB
C++
97 lines
4.0 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#include <optional>
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#include "toolchain/base/kind_switch.h"
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#include "toolchain/check/context.h"
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#include "toolchain/check/convert.h"
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#include "toolchain/check/handle.h"
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#include "toolchain/check/inst.h"
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#include "toolchain/check/literal.h"
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#include "toolchain/check/name_lookup.h"
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#include "toolchain/check/operator.h"
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#include "toolchain/check/type.h"
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#include "toolchain/diagnostics/diagnostic.h"
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#include "toolchain/sem_ir/expr_info.h"
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#include "toolchain/sem_ir/inst.h"
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#include "toolchain/sem_ir/typed_insts.h"
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namespace Carbon::Check {
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auto HandleParseNode(Context& /*context*/, Parse::IndexExprStartId /*node_id*/)
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-> bool {
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// Leave the expression on the stack for IndexExpr.
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return true;
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}
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// Performs an index with base expression `operand_inst_id` and
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// `operand_type_id` for types that are not an array. This checks if
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// the base expression implements the `IndexWith` interface; if so, uses the
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// `At` associative method, otherwise prints a diagnostic.
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static auto PerformIndexWith(Context& context, Parse::NodeId node_id,
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SemIR::InstId operand_inst_id,
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SemIR::InstId index_inst_id) -> SemIR::InstId {
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SemIR::InstId args[] = {context.types().GetTypeInstId(
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context.insts().Get(index_inst_id).type_id())};
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Operator op{.interface_name = CoreIdentifier::IndexWith,
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.interface_args_ref = args,
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.op_name = CoreIdentifier::At};
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return BuildBinaryOperator(context, node_id, op, operand_inst_id,
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index_inst_id);
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}
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auto HandleParseNode(Context& context, Parse::IndexExprId node_id) -> bool {
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auto index_inst_id = context.node_stack().PopExpr();
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auto operand_inst_id = context.node_stack().PopExpr();
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operand_inst_id = ConvertToValueOrRefExpr(context, operand_inst_id);
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auto operand_inst = context.insts().Get(operand_inst_id);
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auto operand_type_id = operand_inst.type_id();
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CARBON_KIND_SWITCH(context.types().GetAsInst(operand_type_id)) {
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case CARBON_KIND(SemIR::ArrayType array_type): {
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auto cast_index_id = ConvertToValueOfType(
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context, SemIR::LocId(index_inst_id), index_inst_id,
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// TODO: Replace this with impl lookup rather than hardcoding `i32`.
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MakeIntType(context, node_id, SemIR::IntKind::Signed,
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context.ints().Add(32)));
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auto array_cat =
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SemIR::GetExprCategory(context.sem_ir(), operand_inst_id);
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if (array_cat == SemIR::ExprCategory::Value) {
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// If the operand is an array value, convert it to an ephemeral
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// reference to an array so we can perform a primitive indexing into it.
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operand_inst_id = AddInst<SemIR::ValueAsRef>(
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context, node_id,
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{.type_id = operand_type_id, .value_id = operand_inst_id});
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}
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// Constant evaluation will perform a bounds check on this array indexing
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// if the index is constant.
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auto elem_id = AddInst<SemIR::ArrayIndex>(
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context, node_id,
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{.type_id = context.types().GetTypeIdForTypeInstId(
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array_type.element_type_inst_id),
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.array_id = operand_inst_id,
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.index_id = cast_index_id});
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if (array_cat != SemIR::ExprCategory::DurableRef) {
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// Indexing a durable reference gives a durable reference expression.
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// Indexing anything else gives a value expression.
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// TODO: This should be replaced by a choice between using `IndexWith`
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// and `IndirectIndexWith`.
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elem_id = ConvertToValueExpr(context, elem_id);
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}
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context.node_stack().Push(node_id, elem_id);
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return true;
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}
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default: {
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auto elem_id =
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PerformIndexWith(context, node_id, operand_inst_id, index_inst_id);
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context.node_stack().Push(node_id, elem_id);
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return true;
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}
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}
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}
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} // namespace Carbon::Check
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