mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-24 22:02:23 +01:00
Richard Smith
202d3f5993
Add semantic analysis and semantics IR building for `if` expressions, and add the first parts of control flow handling to semantics IR. After discussion with @chandlerc, use [block arguments](https://en.wikipedia.org/wiki/Static_single-assignment_form#Block_arguments) to convey values from the two arms of the `if` to the result. For now, only a single block argument is supported, but we should revisit this as we explore more of the requirements of the Semantics IR form. Functions can now contain multiple code blocks, so grab the entry block up-front instead of assuming the entry block will be at the top of the block stack when we reach the end of function emission. Add trivial support for `bool` type literal, because without it we can't write testcases.
72 lines
2.3 KiB
C++
72 lines
2.3 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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#ifndef CARBON_TOOLCHAIN_SEMANTICS_SEMANTICS_NODE_BLOCK_STACK_H_
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#define CARBON_TOOLCHAIN_SEMANTICS_SEMANTICS_NODE_BLOCK_STACK_H_
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#include <type_traits>
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#include "llvm/ADT/SmallVector.h"
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#include "toolchain/semantics/semantics_node.h"
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namespace Carbon {
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// Wraps the stack of node blocks for SemanticsParseTreeHandler.
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//
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// All pushes and pops will be vlogged.
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class SemanticsNodeBlockStack {
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public:
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explicit SemanticsNodeBlockStack(
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llvm::StringLiteral name,
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llvm::SmallVector<llvm::SmallVector<SemanticsNodeId>>& node_blocks,
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llvm::raw_ostream* vlog_stream)
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: name_(name), node_blocks_(&node_blocks), vlog_stream_(vlog_stream) {}
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// Pushes a new node block. It will be invalid unless PeekForAdd is called in
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// order to support lazy allocation.
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auto Push() -> void;
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// Allocates and pushes a new node block.
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auto PushForAdd() -> SemanticsNodeBlockId {
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Push();
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return PeekForAdd();
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}
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// Peeks at the top node block. This does not trigger lazy allocation, so the
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// returned node block may be invalid.
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auto Peek() -> SemanticsNodeBlockId { return stack_.back(); }
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// Returns the top node block, allocating one if it's still invalid.
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auto PeekForAdd() -> SemanticsNodeBlockId;
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// Pops the top node block. This will always return a valid node block;
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// SemanticsNodeBlockId::Empty is returned if one wasn't allocated.
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auto Pop() -> SemanticsNodeBlockId;
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// Prints the stack for a stack dump.
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auto PrintForStackDump(llvm::raw_ostream& output) const -> void;
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auto empty() const -> bool { return stack_.empty(); }
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auto size() const -> size_t { return stack_.size(); }
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private:
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// A name for debugging.
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llvm::StringLiteral name_;
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// The underlying node block storage on SemanticsIR. Always non-null.
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llvm::SmallVector<llvm::SmallVector<SemanticsNodeId>>* const node_blocks_;
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// Whether to print verbose output.
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llvm::raw_ostream* vlog_stream_;
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// The actual stack.
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// PushEntry and PopEntry control modification in order to centralize
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// vlogging.
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llvm::SmallVector<SemanticsNodeBlockId> stack_;
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};
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} // namespace Carbon
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#endif // CARBON_TOOLCHAIN_SEMANTICS_SEMANTICS_NODE_BLOCK_STACK_H_
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