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https://github.com/carbon-language/carbon-lang.git
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Chandler Carruth
1b2eb42c5a
An invalid parse due to an error token isn't likely a great diagnostic as it will already have been diagnosed by the lexer. A common case to start handling that is when the parser encounters an invalid token when expecting an expression. This removes a number of unhelpful diagnostics after the lexer has done a good job diagnosing. This also means that there may be parse tree errors that aren't diagnosed when there are lexer-diagnosed errors, so track that. Follow-up to #4430 that almost finishes addressing its diagnostic TODO.
67 lines
2.4 KiB
C++
67 lines
2.4 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/parse/parse.h"
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#include "common/check.h"
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#include "toolchain/base/pretty_stack_trace_function.h"
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#include "toolchain/parse/context.h"
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#include "toolchain/parse/handle.h"
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#include "toolchain/parse/node_kind.h"
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namespace Carbon::Parse {
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auto HandleInvalid(Context& context) -> void {
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CARBON_FATAL("The Invalid state shouldn't be on the stack: {0}",
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context.PopState());
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}
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auto Parse(Lex::TokenizedBuffer& tokens, DiagnosticConsumer& consumer,
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llvm::raw_ostream* vlog_stream) -> Tree {
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Lex::TokenDiagnosticConverter converter(&tokens);
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ErrorTrackingDiagnosticConsumer err_tracker(consumer);
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Lex::TokenDiagnosticEmitter emitter(converter, err_tracker);
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// Delegate to the parser.
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Tree tree(tokens);
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Context context(tree, tokens, emitter, vlog_stream);
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PrettyStackTraceFunction context_dumper(
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[&](llvm::raw_ostream& output) { context.PrintForStackDump(output); });
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context.AddLeafNode(NodeKind::FileStart,
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context.ConsumeChecked(Lex::TokenKind::FileStart));
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context.PushState(State::DeclScopeLoop);
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while (!context.state_stack().empty()) {
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switch (context.state_stack().back().state) {
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#define CARBON_PARSE_STATE(Name) \
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case State::Name: \
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Handle##Name(context); \
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break;
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#include "toolchain/parse/state.def"
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}
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}
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context.AddLeafNode(NodeKind::FileEnd, *context.position());
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// Mark the tree as potentially having errors if there were errors coming in
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// from the tokenized buffer or we diagnosed new errors.
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tree.set_has_errors(tokens.has_errors() || err_tracker.seen_error());
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if (auto verify = tree.Verify(); !verify.ok()) {
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// TODO: This is temporarily printing to stderr directly during development.
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// If we can, restrict this to a subtree with the error and add it to the
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// stack trace (such as with PrettyStackTraceFunction). Otherwise, switch
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// back to vlog_stream prior to broader distribution so that end users are
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// hopefully comfortable copy-pasting stderr when there are bugs in tree
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// construction.
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tree.Print(llvm::errs());
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CARBON_FATAL("Invalid tree returned by Parse(): {0}", verify.error());
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}
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return tree;
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}
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} // namespace Carbon::Parse
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