[clang][deps] Add module files for input dependencies earlier

I originally thought we needed to add module file inputs for modular
deps at the same time as outputs because they depend on the
lookupModuleOutput callback, but this is not the case: they only depend
on the callback results for other modules, which have already been
computed by this point. So move them earlier so that they're set in the
CompilerInvocation at the same time as other inputs. This makes the
code easier to understand.

This change is effectively NFC, though it technically changes the module
exact value of the context hash.

Differential Revision: https://reviews.llvm.org/D142392

diff --git a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
index 1ae35c2..f970833 100644 (file)
--- a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
+++ b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
@@ -55,11 +55,6 @@ static std::vector<std::string> splitString(std::string S, char Separator) {
 
 void ModuleDepCollector::addOutputPaths(CompilerInvocation &CI,
                                         ModuleDeps &Deps) {
-  // These are technically *inputs* to the compilation, but we populate them
-  // here in order to make \c getModuleContextHash() independent of
-  // \c lookupModuleOutput().
-  addModuleFiles(CI, Deps.ClangModuleDeps);
-
   CI.getFrontendOpts().OutputFile =
       Consumer.lookupModuleOutput(Deps.ID, ModuleOutputKind::ModuleFile);
   if (!CI.getDiagnosticOpts().DiagnosticSerializationFile.empty())
@@ -156,6 +151,9 @@ ModuleDepCollector::makeInvocationForModuleBuildWithoutOutputs(
   for (const auto &PrebuiltModule : Deps.PrebuiltModuleDeps)
     CI.getFrontendOpts().ModuleFiles.push_back(PrebuiltModule.PCMFile);
 
+  // Add module file inputs from dependencies.
+  addModuleFiles(CI, Deps.ClangModuleDeps);
+
   // Remove any macro definitions that are explicitly ignored.
   if (!CI.getHeaderSearchOpts().ModulesIgnoreMacros.empty()) {
     llvm::erase_if(