mirror of
https://github.com/carbon-language/carbon-lang.git
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Richard Smith
4b69264cb1
Add validation that every code block in a function is terminated by a sequence of terminating instructions, and that terminators don't appear anywhere else in code blocks. This required tracking whether we're in a reachable code block. That's done on the fly when we create a new code block; the new `SemanticsNodeBlockId::Unreachable` is used to represent the case where we're not actually creating a code block because we're in unreachable code.
93 lines
3.0 KiB
C++
93 lines
3.0 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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#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_ir.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(llvm::StringLiteral name,
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SemanticsIR& semantics_ir,
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llvm::raw_ostream* vlog_stream)
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: name_(name), semantics_ir_(&semantics_ir), vlog_stream_(vlog_stream) {}
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// Pushes an existing node block.
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auto Push(SemanticsNodeBlockId id) -> void;
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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 { Push(SemanticsNodeBlockId::Invalid); }
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// Pushes a new unreachable code block.
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auto PushUnreachable() -> void { Push(SemanticsNodeBlockId::Unreachable); }
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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 {
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CARBON_CHECK(!stack_.empty()) << "no current block";
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return stack_.back();
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}
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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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// Pops the top node block, ensuring that it is lazily allocated if it's
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// empty. For use when more nodes will be added to the block later.
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auto PopForAdd() -> SemanticsNodeBlockId {
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PeekForAdd();
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return Pop();
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}
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// Returns whether the current block is statically reachable.
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auto is_current_block_reachable() -> bool {
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return Peek() != SemanticsNodeBlockId::Unreachable;
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}
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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 SemanticsIR instance. Always non-null.
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SemanticsIR* semantics_ir_;
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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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