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Jon Ross-PerkinsandGeoff Romer
03e693873b
Right now, return_scope_stack is being used to determine whether logic
is in a function scope. However, we need to handle nested entities
inside function scopes. For example where this crashes right now:
```
base class C(B:! bool) {}
fn F() {
class B {
extend base: C(true or false);
}
}
```
This is doing a few things to make this kind of code not crash:
- Split `scope_stack().Push` into `PushForDeclName`, `PushForEntity`,
`PushForExpr`, and `PushForFunction` so that better decisions can be
made about behaviors.
- Hide `return_scope_stack` in the API, instead using interfaces to get
at the underlying data.
- Also using `PushForFunction` to update it similar to the other stacks
that `ScopeStack` manages.
- Add `IsInFunctionScope` as the best way to determine presence in
function scope.
- Remove `PeekIsLexicalScope` since destruction really wants function
scope information anyways.
- Clean up `destroy_id_stack` handling to be for function scopes rather
than lexical scopes.
- Return after related `context.TODO`s in a couple more spots, so that
code doesn't proceed to add control flow in spite of the lack of
support.
---------
Co-authored-by: Geoff Romer <gromer@google.com>
100 lines
3.8 KiB
C++
100 lines
3.8 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/literal.h"
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namespace Carbon::Check {
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auto HandleParseNode(Context& context, Parse::IfExprIfId node_id) -> bool {
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// Alias node_id for if/then/else consistency.
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auto& if_node = node_id;
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auto [cond_node, cond_value_id] = context.node_stack().PopExprWithNodeId();
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// Convert the condition to `bool`, and branch on it.
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cond_value_id = ConvertToBoolValue(context, if_node, cond_value_id);
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context.node_stack().Push(cond_node, cond_value_id);
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auto then_block_id =
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AddDominatedBlockAndBranchIf(context, if_node, cond_value_id);
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auto else_block_id = AddDominatedBlockAndBranch(context, if_node);
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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(if_node, else_block_id);
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return true;
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}
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// If the operand is an `IntLiteral`, convert it to a suitably-sized `Int` type.
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// TODO: For now we always pick `i32`.
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static auto DecayIntLiteralToSizedInt(Context& context, Parse::NodeId node_id,
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SemIR::InstId operand_id)
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-> SemIR::InstId {
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if (context.types().GetInstId(context.insts().Get(operand_id).type_id()) ==
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SemIR::IntLiteralType::TypeInstId) {
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operand_id = ConvertToValueOfType(
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context, node_id, operand_id,
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MakeIntType(context, node_id, SemIR::IntKind::Signed,
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context.ints().Add(32)));
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}
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return operand_id;
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}
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auto HandleParseNode(Context& context, Parse::IfExprThenId node_id) -> bool {
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auto then_value_id = context.node_stack().PopExpr();
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auto else_block_id = context.node_stack().Peek<Parse::NodeKind::IfExprIf>();
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// Convert the first operand to a value.
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then_value_id = ConvertToValueExpr(context, then_value_id);
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then_value_id = DecayIntLiteralToSizedInt(context, node_id, then_value_id);
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// Start 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, then_value_id);
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return true;
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}
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auto HandleParseNode(Context& context, Parse::IfExprElseId node_id) -> bool {
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if (!context.scope_stack().IsInFunctionScope()) {
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return context.TODO(node_id,
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"Control flow expressions are currently only supported "
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"inside functions.");
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}
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// Alias node_id for if/then/else consistency.
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auto& else_node = node_id;
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auto else_value_id = context.node_stack().PopExpr();
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auto then_value_id = context.node_stack().Pop<Parse::NodeKind::IfExprThen>();
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auto [if_node, _] =
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context.node_stack().PopWithNodeId<Parse::NodeKind::IfExprIf>();
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auto cond_value_id = context.node_stack().PopExpr();
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// Convert the `else` value to the `then` value's type, and finish the `else`
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// block.
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// TODO: Find a common type, and convert both operands to it instead.
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auto result_type_id = context.insts().Get(then_value_id).type_id();
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else_value_id =
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ConvertToValueOfType(context, else_node, else_value_id, result_type_id);
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// Create a resumption block and branches to it.
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auto chosen_value_id = AddConvergenceBlockWithArgAndPush(
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context, if_node, {else_value_id, then_value_id});
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SetBlockArgResultBeforeConstantUse(context, chosen_value_id, cond_value_id,
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then_value_id, else_value_id);
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// Push the result value.
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context.node_stack().Push(else_node, chosen_value_id);
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return true;
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}
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} // namespace Carbon::Check
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