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https://github.com/carbon-language/carbon-lang.git
synced 2026-09-24 21:30:12 +01:00
Richard Smith
703529fc55
Instead of tracking the cleanup scope depth on entry to each scope, track an "ambient" cleanup scope depth that's *after* the destructors of local variables in that scope. This gets increased to include the destructors of local variables when we create a name-binding declaration. Then, when we reach a point where temporaries should be destroyed, run cleanups that are after the ambient cleanup scope depth on the stack. This happens: * At the `;` of a statement expression. * At the `)` of an `if` or `while` statement. * After performing the implied `HasValue()` call in a `for` statement. Per informal agreement with leads, this means we lifetime-extend all temporaries created in the initializer of a name-binding declaration to the full scope of that declaration, but that temporaries created in an expression statement are destroyed at the `;`.
85 lines
2.9 KiB
C++
85 lines
2.9 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 "toolchain/check/context.h"
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#include "toolchain/check/control_flow.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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namespace Carbon::Check {
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auto HandleParseNode(Context& /*context*/,
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Parse::IfConditionStartId /*node_id*/) -> bool {
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return true;
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}
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auto HandleParseNode(Context& context, Parse::IfConditionId node_id) -> bool {
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// Convert the condition to `bool`.
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auto cond_value_id = context.node_stack().PopExpr();
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cond_value_id = ConvertToBoolValue(context, node_id, cond_value_id);
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// Destroy any temporaries created in the condition.
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AddAndDiscardTemporaryCleanups(context);
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// Create the then block and the else block, and branch to the right one. If
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// there is no `else`, the then block will terminate with a branch to the
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// else block, which will be reused as the resumption block.
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auto then_block_id =
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AddDominatedBlockAndBranchIf(context, node_id, cond_value_id);
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auto else_block_id = AddDominatedBlockAndBranch(context, node_id);
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// Start emitting the `then` block.
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context.inst_block_stack().Pop();
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context.inst_block_stack().Push(then_block_id);
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context.region_stack().AddToRegion(then_block_id, node_id);
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context.node_stack().Push(node_id, else_block_id);
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return true;
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}
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auto HandleParseNode(Context& context, Parse::IfStatementElseId node_id)
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-> bool {
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auto else_block_id = context.node_stack().Pop<Parse::NodeKind::IfCondition>();
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// Switch to emitting the `else` block.
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context.inst_block_stack().Push(else_block_id);
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context.region_stack().AddToRegion(else_block_id, node_id);
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context.node_stack().Push(node_id);
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return true;
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}
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auto HandleParseNode(Context& context, Parse::IfStatementId node_id) -> bool {
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switch (auto kind = context.node_stack().PeekNodeKind()) {
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case Parse::NodeKind::IfCondition: {
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// Branch from then block to else block, and start emitting the else
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// block.
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auto else_block_id =
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context.node_stack().Pop<Parse::NodeKind::IfCondition>();
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AddInst<SemIR::Branch>(context, node_id, {.target_id = else_block_id});
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context.inst_block_stack().Pop();
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context.inst_block_stack().Push(else_block_id);
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context.region_stack().AddToRegion(else_block_id, node_id);
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break;
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}
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case Parse::NodeKind::IfStatementElse: {
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// Branch from the then and else blocks to a new resumption block.
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context.node_stack()
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.PopAndDiscardSoloNodeId<Parse::NodeKind::IfStatementElse>();
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AddConvergenceBlockAndPush(context, node_id, /*num_blocks=*/2);
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break;
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}
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default: {
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CARBON_FATAL("Unexpected parse node at start of `if`: {0}", kind);
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}
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}
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return true;
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}
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} // namespace Carbon::Check
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