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Stub out a tool that runs a script over a Swift AST.
The tool is currently hard-coded to find functions in the SwiftUI library that take parameters of type `(...) -> T` where `T: View` but where the parameter isn't annotated with `@ViewBuilder`. The long-term vision here, of course, is that this reads and interprets a script file, but that's quite a bit more work (especially to generate a million bindings to the AST). In the meantime, I think having a functional harness that people familiar with the C++ API can easily hack on to make their own tools is still pretty useful. The harness does try to open a script file and lex the first token of it, because that's exactly as far as I got before deciding to hard-code the query I wanted. Since this input is otherwise ignored, you can just point the tool at any old `.swift` file (or just an empty file) and it'll be fine.
1 parent 48024ec commit d53a88d

8 files changed

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lines changed

‎tools/CMakeLists.txt

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@@ -28,6 +28,7 @@ add_swift_tool_subdirectory(sil-nm)
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add_swift_tool_subdirectory(sil-passpipeline-dumper)
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add_swift_tool_subdirectory(swift-llvm-opt)
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add_swift_tool_subdirectory(swift-api-digester)
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add_swift_tool_subdirectory(swift-ast-script)
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add_swift_tool_subdirectory(swift-syntax-test)
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add_swift_tool_subdirectory(swift-refactor)
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if(SWIFT_BUILD_SYNTAXPARSERLIB)

‎tools/swift-ast-script/ASTScript.h

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//===--- ASTScript.h - AST script type --------------------------*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// The AST for a swift-ast-script script.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_SCRIPTING_ASTSCRIPT_H
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#define SWIFT_SCRIPTING_ASTSCRIPT_H
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#include "swift/Basic/LLVM.h"
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namespace swift {
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namespace scripting {
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class ASTScriptConfiguration;
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class ASTScript {
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ASTScriptConfiguration &Config;
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public:
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ASTScript(ASTScriptConfiguration &config) : Config(config) {}
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static std::unique_ptr<ASTScript> parse(ASTScriptConfiguration &config);
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bool execute() const;
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};
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}
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}
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#endif

‎tools/swift-ast-script/ASTScriptConfiguration.cpp

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//===--- ASTScriptConfiguration.cpp ---------------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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///
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/// Configuration parsing for an AST script.
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///
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//===----------------------------------------------------------------------===//
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#include "ASTScriptConfiguration.h"
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#include "swift/Basic/QuotedString.h"
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace swift;
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using namespace scripting;
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std::unique_ptr<ASTScriptConfiguration>
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ASTScriptConfiguration::parse(CompilerInstance &compiler,
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ArrayRef<const char *> args) {
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bool hadError = false;
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std::unique_ptr<ASTScriptConfiguration> result(
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new ASTScriptConfiguration(compiler));
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#define emitError(WHAT) do { \
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llvm::errs() << "error: " << WHAT << "\n"; \
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hadError = true; \
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} while (0)
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auto popArg = [&](const char *what) -> StringRef {
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// Gracefully handle the case of running out of arguments.
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if (args.empty()) {
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assert(what && "expected explanation here!");
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emitError(what);
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return "";
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}
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auto arg = args.front();
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args = args.slice(1);
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return arg;
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};
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auto setScriptFile = [&](StringRef filename) {
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if (!result->ScriptFile.empty()) {
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emitError("multiple script files ("
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<< QuotedString(result->ScriptFile)
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<< ", "
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<< QuotedString(filename)
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<< ")");
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}
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result->ScriptFile = filename;
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};
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// Parse the arguments.
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while (!hadError && !args.empty()) {
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StringRef arg = popArg(nullptr);
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if (!arg.startswith("-")) {
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setScriptFile(arg);
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} else if (arg == "-f") {
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StringRef filename = popArg("expected path after -f");
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if (!hadError)
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setScriptFile(filename);
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} else if (arg == "-h" || arg == "--help") {
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llvm::errs()
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<< "usage: swift-ast-script <script-args> -- <compiler-args\n"
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"accepted script arguments:\n"
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" <filename>\n"
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" -f <filename>\n"
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" Specify the file to use as the script; required argument\n";
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hadError = true;
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} else {
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emitError("unknown argument " << QuotedString(arg));
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}
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}
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// Check well-formedness.
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if (!hadError) {
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if (result->ScriptFile.empty()) {
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emitError("script file is required");
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}
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}
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if (hadError)
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result.reset();
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return result;
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}

‎tools/swift-ast-script/ASTScriptConfiguration.h

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//===--- ASTScriptConfiguration.h - AST script configuration ----*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// Types for configuring an AST script invocation.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_SCRIPTING_ASTSCRIPTCONFIGURATION_H
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#define SWIFT_SCRIPTING_ASTSCRIPTCONFIGURATION_H
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#include "swift/Basic/LLVM.h"
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#include "llvm/ADT/StringRef.h"
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namespace swift {
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class CompilerInstance;
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namespace scripting {
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/// A configuration for working with an ASTScript.
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class ASTScriptConfiguration {
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ASTScriptConfiguration(CompilerInstance &compiler) : Compiler(compiler) {}
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public:
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CompilerInstance &Compiler;
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StringRef ScriptFile;
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/// Attempt to parse this configuration.
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///
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/// Returns null if there's a problem.
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static std::unique_ptr<ASTScriptConfiguration>
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parse(CompilerInstance &compiler, ArrayRef<const char *> args);
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};
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}
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}
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#endif

‎tools/swift-ast-script/ASTScriptEvaluator.cpp

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//===--- ASTScriptEvaluator.cpp -------------------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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///
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/// AST script evaluation.
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///
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//===----------------------------------------------------------------------===//
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#include "ASTScript.h"
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#include "ASTScriptConfiguration.h"
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#include "swift/AST/ASTMangler.h"
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#include "swift/AST/ASTWalker.h"
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#include "swift/AST/Decl.h"
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#include "swift/AST/NameLookup.h"
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#include "swift/Frontend/Frontend.h"
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using namespace swift;
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using namespace scripting;
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namespace {
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class ASTScriptWalker : public ASTWalker {
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const ASTScript &Script;
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ProtocolDecl *ViewProtocol;
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public:
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ASTScriptWalker(const ASTScript &script, ProtocolDecl *viewProtocol)
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: Script(script), ViewProtocol(viewProtocol) {}
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bool walkToDeclPre(Decl *D) override {
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visit(D);
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return true;
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}
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void visit(const Decl *D) {
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auto fn = dyn_cast<AbstractFunctionDecl>(D);
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if (!fn) return;
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// Suppress warnings.
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(void) Script;
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for (auto param : *fn->getParameters()) {
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// The parameter must have function type.
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auto paramType = param->getInterfaceType();
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auto paramFnType = paramType->getAs<FunctionType>();
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if (!paramFnType) continue;
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// The parameter function must return a type parameter that
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// conforms to SwiftUI.View.
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auto paramResultType = paramFnType->getResult();
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if (!paramResultType->isTypeParameter()) continue;
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auto sig = fn->getGenericSignature();
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if (!sig->conformsToProtocol(paramResultType, ViewProtocol)) continue;
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// The parameter must not be a @ViewBuilder parameter.
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if (param->getFunctionBuilderType()) continue;
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// Print the function.
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printDecl(fn);
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}
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}
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void printDecl(const ValueDecl *decl) {
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// FIXME: there's got to be some better way to print an exact reference
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// to a declaration, including its context.
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printDecl(llvm::outs(), decl);
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llvm::outs() << "\n";
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}
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void printDecl(llvm::raw_ostream &out, const ValueDecl *decl) {
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if (auto accessor = dyn_cast<AccessorDecl>(decl)) {
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printDecl(out, accessor->getStorage());
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out << ".(accessor)";
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} else {
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printDeclContext(out, decl->getDeclContext());
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out << decl->getFullName();
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}
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}
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void printDeclContext(llvm::raw_ostream &out, const DeclContext *dc) {
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if (!dc) return;
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if (auto module = dyn_cast<ModuleDecl>(dc)) {
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out << module->getName() << ".";
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} else if (auto extension = dyn_cast<ExtensionDecl>(dc)) {
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printDecl(out, extension->getExtendedNominal());
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out << ".";
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} else if (auto decl = dyn_cast_or_null<ValueDecl>(dc->getAsDecl())) {
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printDecl(out, decl);
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out << ".";
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} else {
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printDeclContext(out, dc->getParent());
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}
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}
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};
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}
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bool ASTScript::execute() const {
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// Hardcode the actual query we want to execute here.
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auto &ctx = Config.Compiler.getASTContext();
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auto swiftUI = ctx.getLoadedModule(ctx.getIdentifier("SwiftUI"));
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if (!swiftUI) {
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llvm::errs() << "error: SwiftUI module not loaded\n";
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return true;
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}
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UnqualifiedLookup viewLookup(ctx.getIdentifier("View"), swiftUI, nullptr);
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auto viewProtocol =
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dyn_cast_or_null<ProtocolDecl>(viewLookup.getSingleTypeResult());
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if (!viewProtocol) {
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llvm::errs() << "error: couldn't find SwiftUI.View protocol\n";
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return true;
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}
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SmallVector<Decl*, 128> topLevelDecls;
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swiftUI->getTopLevelDecls(topLevelDecls);
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llvm::errs() << "found " << topLevelDecls.size() << " top-level declarations\n";
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ASTScriptWalker walker(*this, viewProtocol);
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for (auto decl : topLevelDecls) {
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decl->walk(walker);
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}
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return false;
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}

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