[NFC] Use the Correct const-Qualification in Dependency Code

T *const does not prevent logically non-const accesses to the underlying data, it merely indicates that the pointer value itself is const. This modifier can be cast off by a copy, so it's not generally what you want here. Switch to const T * instead.

Author: CodaFi

include/swift/AST/FineGrainedDependencies.h

@@ -351,7 +351,7 @@ class BiIndexedTwoStageMap {
 ///
 /// \Note The returned graph should not be escaped from the callback.
 bool withReferenceDependencies(
-    llvm::PointerUnion<ModuleDecl *, SourceFile *> MSF,
+    llvm::PointerUnion<const ModuleDecl *, const SourceFile *> MSF,
     const DependencyTracker &depTracker, StringRef outputPath,
     bool alsoEmitDotFile, llvm::function_ref<bool(SourceFileDepGraph &&)>);
 

lib/AST/FrontendSourceFileDepGraphFactory.cpp

@@ -193,16 +193,16 @@ std::string DependencyKey::computeNameForProvidedEntity<
 //==============================================================================
 
 bool fine_grained_dependencies::withReferenceDependencies(
-    llvm::PointerUnion<ModuleDecl *, SourceFile *> MSF,
+    llvm::PointerUnion<const ModuleDecl *, const SourceFile *> MSF,
     const DependencyTracker &depTracker, StringRef outputPath,
     bool alsoEmitDotFile,
     llvm::function_ref<bool(SourceFileDepGraph &&)> cont) {
-  if (auto *MD = MSF.dyn_cast<ModuleDecl *>()) {
+  if (auto *MD = MSF.dyn_cast<const ModuleDecl *>()) {
     SourceFileDepGraph g =
         ModuleDepGraphFactory(MD, alsoEmitDotFile).construct();
     return cont(std::move(g));
   } else {
-    auto *SF = MSF.get<SourceFile *>();
+    auto *SF = MSF.get<const SourceFile *>();
     SourceFileDepGraph g = FrontendSourceFileDepGraphFactory(
                                SF, outputPath, depTracker, alsoEmitDotFile)
                                .construct();
@@ -215,22 +215,22 @@ bool fine_grained_dependencies::withReferenceDependencies(
 //==============================================================================
 
 FrontendSourceFileDepGraphFactory::FrontendSourceFileDepGraphFactory(
-    SourceFile *SF, StringRef outputPath, const DependencyTracker &depTracker,
-    const bool alsoEmitDotFile)
+    const SourceFile *SF, StringRef outputPath,
+    const DependencyTracker &depTracker, const bool alsoEmitDotFile)
     : AbstractSourceFileDepGraphFactory(
-          SF->getASTContext().hadError(),
-          outputPath, getInterfaceHash(SF), alsoEmitDotFile,
-          SF->getASTContext().Diags),
+          SF->getASTContext().hadError(), outputPath, getInterfaceHash(SF),
+          alsoEmitDotFile, SF->getASTContext().Diags),
       SF(SF), depTracker(depTracker) {}
 
 /// Centralize the invariant that the fingerprint of the whole file is the
 /// interface hash
-std::string FrontendSourceFileDepGraphFactory::getFingerprint(SourceFile *SF) {
+std::string
+FrontendSourceFileDepGraphFactory::getFingerprint(const SourceFile *SF) {
   return getInterfaceHash(SF);
 }
 
 std::string
-FrontendSourceFileDepGraphFactory::getInterfaceHash(SourceFile *SF) {
+FrontendSourceFileDepGraphFactory::getInterfaceHash(const SourceFile *SF) {
   llvm::SmallString<32> interfaceHash;
   SF->getInterfaceHash(interfaceHash);
   return interfaceHash.str().str();
@@ -415,7 +415,7 @@ void FrontendSourceFileDepGraphFactory::addAllDefinedDecls() {
 namespace {
 /// Extracts uses out of a SourceFile
 class UsedDeclEnumerator {
-  SourceFile *SF;
+  const SourceFile *SF;
   const DependencyTracker &depTracker;
   StringRef swiftDeps;
 
@@ -427,16 +427,16 @@ class UsedDeclEnumerator {
 
 public:
   UsedDeclEnumerator(
-      SourceFile *SF, const DependencyTracker &depTracker, StringRef swiftDeps,
+      const SourceFile *SF, const DependencyTracker &depTracker,
+      StringRef swiftDeps,
       function_ref<void(const DependencyKey &, const DependencyKey &)>
           createDefUse)
       : SF(SF), depTracker(depTracker), swiftDeps(swiftDeps),
         sourceFileInterface(DependencyKey::createKeyForWholeSourceFile(
             DeclAspect::interface, swiftDeps)),
         sourceFileImplementation(DependencyKey::createKeyForWholeSourceFile(
             DeclAspect::implementation, swiftDeps)),
-        createDefUse(createDefUse) {
-  }
+        createDefUse(createDefUse) {}
 
 public:
   void enumerateAllUses() {
@@ -517,10 +517,11 @@ void FrontendSourceFileDepGraphFactory::addAllUsedDecls() {
 // MARK: ModuleDepGraphFactory
 //==============================================================================
 
-ModuleDepGraphFactory::ModuleDepGraphFactory(ModuleDecl *Mod, bool emitDot)
-    : AbstractSourceFileDepGraphFactory(
-          Mod->getASTContext().hadError(),
-          Mod->getNameStr(), "0xBADBEEF", emitDot, Mod->getASTContext().Diags),
+ModuleDepGraphFactory::ModuleDepGraphFactory(const ModuleDecl *Mod,
+                                             bool emitDot)
+    : AbstractSourceFileDepGraphFactory(Mod->getASTContext().hadError(),
+                                        Mod->getNameStr(), "0xBADBEEF", emitDot,
+                                        Mod->getASTContext().Diags),
       Mod(Mod) {}
 
 void ModuleDepGraphFactory::addAllDefinedDecls() {

lib/AST/FrontendSourceFileDepGraphFactory.h

@@ -23,29 +23,29 @@ namespace fine_grained_dependencies {
 
 class FrontendSourceFileDepGraphFactory
     : public AbstractSourceFileDepGraphFactory {
-  SourceFile *const SF;
+  const SourceFile *SF;
   const DependencyTracker &depTracker;
 
 public:
-  FrontendSourceFileDepGraphFactory(SourceFile *SF, StringRef outputPath,
+  FrontendSourceFileDepGraphFactory(const SourceFile *SF, StringRef outputPath,
                                     const DependencyTracker &depTracker,
                                     bool alsoEmitDotFile);
 
   ~FrontendSourceFileDepGraphFactory() override = default;
 
 private:
-  static std::string getFingerprint(SourceFile *SF);
-  static std::string getInterfaceHash(SourceFile *SF);
+  static std::string getFingerprint(const SourceFile *SF);
+  static std::string getInterfaceHash(const SourceFile *SF);
 
   void addAllDefinedDecls() override;
   void addAllUsedDecls() override;
 };
 
 class ModuleDepGraphFactory : public AbstractSourceFileDepGraphFactory {
-  ModuleDecl *const Mod;
+  const ModuleDecl *Mod;
 
 public:
-  ModuleDepGraphFactory(ModuleDecl *Mod, bool emitDot);
+  ModuleDepGraphFactory(const ModuleDecl *Mod, bool emitDot);
 
   ~ModuleDepGraphFactory() override = default;
 

lib/FrontendTool/FrontendTool.cpp

@@ -116,8 +116,8 @@ emitLoadedModuleTraceForAllPrimariesIfNeeded(ModuleDecl *mainModule,
                                              const FrontendOptions &opts) {
   opts.InputsAndOutputs.forEachInputProducingSupplementaryOutput(
       [&](const InputFile &input) -> bool {
-        return emitLoadedModuleTraceIfNeeded(mainModule, depTracker, opts,
-                                             input);
+        return swift::emitLoadedModuleTraceIfNeeded(mainModule, depTracker,
+                                                    opts, input);
       });
 }
 

lib/FrontendTool/LoadedModuleTrace.cpp

@@ -699,7 +699,7 @@ bool swift::emitLoadedModuleTraceIfNeeded(ModuleDecl *mainModule,
   assert(!ctxt.hadError() &&
          "We should've already exited earlier if there was an error.");
 
-  StringRef loadedModuleTracePath = input.loadedModuleTracePath();
+  auto loadedModuleTracePath = input.loadedModuleTracePath();
   if (loadedModuleTracePath.empty())
     return false;
   std::error_code EC;