[clang] [clang][Modules] `checkModuleIsAvailable` should use a const & parameter instead of pointer (PR #67902)

[David Stone via cfe-commits]

https://github.com/davidstone created https://github.com/llvm/llvm-project/pull/67902

The `Module` parameter to `checkModuleIsAvailable` is currently passed by pointer to non-const. However, it requires only const access and it cannot be null. Change this to be a reference to const instead.

This then makes it obvious that it is an input-only parameter, so move it to be before the in-out parameter for diagnostics.

>From 3b7cf88ddf78a1f7fbb15e51a288d7265e262b0d Mon Sep 17 00:00:00 2001
From: David Stone <davidfromonline at gmail.com>
Date: Sun, 1 Oct 2023 00:41:34 -0600
Subject: [PATCH] [clang][Modules] `checkModuleIsAvailable` should use a const
 & parameter instead of pointer

The `Module` parameter to `checkModuleIsAvailable` is currently passed by pointer to non-const. However, it requires only const access and it cannot be null. Change this to be a reference to const instead.

This then makes it obvious that it is an input-only parameter, so move it to be before the in-out parameter for diagnostics.
---
 clang/include/clang/Lex/Preprocessor.h  |  2 +-
 clang/lib/Frontend/CompilerInstance.cpp |  2 +-
 clang/lib/Frontend/FrontendAction.cpp   |  4 ++--
 clang/lib/Lex/PPDirectives.cpp          | 18 ++++++++++--------
 clang/lib/Lex/Pragma.cpp                |  2 +-
 5 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/clang/include/clang/Lex/Preprocessor.h b/clang/include/clang/Lex/Preprocessor.h
index e88164f196c1f7c..b9423640d62f741 100644
--- a/clang/include/clang/Lex/Preprocessor.h
+++ b/clang/include/clang/Lex/Preprocessor.h
@@ -2697,7 +2697,7 @@ class Preprocessor {
   ///         \c false if the module appears to be usable.
   static bool checkModuleIsAvailable(const LangOptions &LangOpts,
                                      const TargetInfo &TargetInfo,
-                                     DiagnosticsEngine &Diags, Module *M);
+                                     const Module &M, DiagnosticsEngine &Diags);
 
   // Module inclusion testing.
   /// Find the module that owns the source or header file that
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index d18371f21a9d86e..d749195585eca5b 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -2116,7 +2116,7 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
 
     // Check whether this module is available.
     if (Preprocessor::checkModuleIsAvailable(getLangOpts(), getTarget(),
-                                             getDiagnostics(), Module)) {
+                                             *Module, getDiagnostics())) {
       getDiagnostics().Report(ImportLoc, diag::note_module_import_here)
         << SourceRange(Path.front().second, Path.back().second);
       LastModuleImportLoc = ImportLoc;
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index 60eac0c6d353048..eb8a96627bb7076 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -510,8 +510,8 @@ static Module *prepareToBuildModule(CompilerInstance &CI,
   }
 
   // Check whether we can build this module at all.
-  if (Preprocessor::checkModuleIsAvailable(CI.getLangOpts(), CI.getTarget(),
-                                           CI.getDiagnostics(), M))
+  if (Preprocessor::checkModuleIsAvailable(CI.getLangOpts(), CI.getTarget(), *M,
+                                           CI.getDiagnostics()))
     return nullptr;
 
   // Inform the preprocessor that includes from within the input buffer should
diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index 7899bfa1c4f5842..e3065c17dc70b43 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -1896,26 +1896,27 @@ static bool trySimplifyPath(SmallVectorImpl<StringRef> &Components,
 
 bool Preprocessor::checkModuleIsAvailable(const LangOptions &LangOpts,
                                           const TargetInfo &TargetInfo,
-                                          DiagnosticsEngine &Diags, Module *M) {
+                                          const Module &M,
+                                          DiagnosticsEngine &Diags) {
   Module::Requirement Requirement;
   Module::UnresolvedHeaderDirective MissingHeader;
   Module *ShadowingModule = nullptr;
-  if (M->isAvailable(LangOpts, TargetInfo, Requirement, MissingHeader,
-                     ShadowingModule))
+  if (M.isAvailable(LangOpts, TargetInfo, Requirement, MissingHeader,
+                    ShadowingModule))
     return false;
 
   if (MissingHeader.FileNameLoc.isValid()) {
     Diags.Report(MissingHeader.FileNameLoc, diag::err_module_header_missing)
         << MissingHeader.IsUmbrella << MissingHeader.FileName;
   } else if (ShadowingModule) {
-    Diags.Report(M->DefinitionLoc, diag::err_module_shadowed) << M->Name;
+    Diags.Report(M.DefinitionLoc, diag::err_module_shadowed) << M.Name;
     Diags.Report(ShadowingModule->DefinitionLoc,
                  diag::note_previous_definition);
   } else {
     // FIXME: Track the location at which the requirement was specified, and
     // use it here.
-    Diags.Report(M->DefinitionLoc, diag::err_module_unavailable)
-        << M->getFullModuleName() << Requirement.second << Requirement.first;
+    Diags.Report(M.DefinitionLoc, diag::err_module_unavailable)
+        << M.getFullModuleName() << Requirement.second << Requirement.first;
   }
   return true;
 }
@@ -2260,8 +2261,9 @@ Preprocessor::ImportAction Preprocessor::HandleHeaderIncludeOrImport(
     // unavailable, diagnose the situation and bail out.
     // FIXME: Remove this; loadModule does the same check (but produces
     // slightly worse diagnostics).
-    if (checkModuleIsAvailable(getLangOpts(), getTargetInfo(), getDiagnostics(),
-                               SuggestedModule.getModule())) {
+    if (checkModuleIsAvailable(getLangOpts(), getTargetInfo(),
+                               *SuggestedModule.getModule(),
+                               getDiagnostics())) {
       Diag(FilenameTok.getLocation(),
            diag::note_implicit_top_level_module_import_here)
           << SuggestedModule.getModule()->getTopLevelModuleName();
diff --git a/clang/lib/Lex/Pragma.cpp b/clang/lib/Lex/Pragma.cpp
index 58da4410dee64a4..35ab42cb6b5ef85 100644
--- a/clang/lib/Lex/Pragma.cpp
+++ b/clang/lib/Lex/Pragma.cpp
@@ -1769,7 +1769,7 @@ struct PragmaModuleBeginHandler : public PragmaHandler {
 
     // If the module isn't available, it doesn't make sense to enter it.
     if (Preprocessor::checkModuleIsAvailable(
-            PP.getLangOpts(), PP.getTargetInfo(), PP.getDiagnostics(), M)) {
+            PP.getLangOpts(), PP.getTargetInfo(), *M, PP.getDiagnostics())) {
       PP.Diag(BeginLoc, diag::note_pp_module_begin_here)
         << M->getTopLevelModuleName();
       return;