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carbon-lang/toolchain/semantics/semantics_node_block_stack.h
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Richard Smith 06ce3b0161 Parsing, semantic analysis, and lowering for and, or, not. (#2897)
Lowering for `and` and `or` is not yet complete because `Branch` lowering isn't done yet.
2023-06-14 13:03:13 -07:00

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2.6 KiB
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// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#ifndef CARBON_TOOLCHAIN_SEMANTICS_SEMANTICS_NODE_BLOCK_STACK_H_
#define CARBON_TOOLCHAIN_SEMANTICS_SEMANTICS_NODE_BLOCK_STACK_H_
#include <type_traits>
#include "llvm/ADT/SmallVector.h"
#include "toolchain/semantics/semantics_node.h"
namespace Carbon {
// Wraps the stack of node blocks for SemanticsParseTreeHandler.
//
// All pushes and pops will be vlogged.
class SemanticsNodeBlockStack {
public:
explicit SemanticsNodeBlockStack(
llvm::StringLiteral name,
llvm::SmallVector<llvm::SmallVector<SemanticsNodeId>>& node_blocks,
llvm::raw_ostream* vlog_stream)
: name_(name), node_blocks_(&node_blocks), vlog_stream_(vlog_stream) {}
// Pushes a new node block. It will be invalid unless PeekForAdd is called in
// order to support lazy allocation.
auto Push() -> void;
// Allocates and pushes a new node block.
auto PushForAdd() -> SemanticsNodeBlockId {
Push();
return PeekForAdd();
}
// Peeks at the top node block. This does not trigger lazy allocation, so the
// returned node block may be invalid.
auto Peek() -> SemanticsNodeBlockId { return stack_.back(); }
// Returns the top node block, allocating one if it's still invalid.
auto PeekForAdd() -> SemanticsNodeBlockId;
// Pops the top node block. This will always return a valid node block;
// SemanticsNodeBlockId::Empty is returned if one wasn't allocated.
auto Pop() -> SemanticsNodeBlockId;
// Pops the top node block, ensuring that it is lazily allocated if it's
// empty. For use when more nodes will be added to the block later.
auto PopForAdd() -> SemanticsNodeBlockId {
PeekForAdd();
return Pop();
}
// Prints the stack for a stack dump.
auto PrintForStackDump(llvm::raw_ostream& output) const -> void;
auto empty() const -> bool { return stack_.empty(); }
auto size() const -> size_t { return stack_.size(); }
private:
// A name for debugging.
llvm::StringLiteral name_;
// The underlying node block storage on SemanticsIR. Always non-null.
llvm::SmallVector<llvm::SmallVector<SemanticsNodeId>>* const node_blocks_;
// Whether to print verbose output.
llvm::raw_ostream* vlog_stream_;
// The actual stack.
// PushEntry and PopEntry control modification in order to centralize
// vlogging.
llvm::SmallVector<SemanticsNodeBlockId> stack_;
};
} // namespace Carbon
#endif // CARBON_TOOLCHAIN_SEMANTICS_SEMANTICS_NODE_BLOCK_STACK_H_