[clang] [clang/DependencyScanning/ModuleDepCollector] Refactor part of `makeCommonInvocationForModuleBuild` into its own function, NFC (PR #88447)

[Argyrios Kyrtzidis via cfe-commits]

https://github.com/akyrtzi updated https://github.com/llvm/llvm-project/pull/88447

>From 8b21183d5e836e0900ce051dab91f0a399ed83e5 Mon Sep 17 00:00:00 2001
From: Argyrios Kyrtzidis <kyrtzidis at apple.com>
Date: Thu, 11 Apr 2024 14:57:40 -0700
Subject: [PATCH] [clang/DependencyScanning/ModuleDepCollector] Refactor part
 of `makeCommonInvocationForModuleBuild` into its own function

The new function is about clearing out benign codegen options and can be applied for PCH invocations as well.
---
 .../DependencyScanning/ModuleDepCollector.h   |  5 +++
 .../DependencyScanning/ModuleDepCollector.cpp | 36 ++++++++++++-------
 clang/test/ClangScanDeps/removed-args.c       | 28 +++++++++++++++
 3 files changed, 57 insertions(+), 12 deletions(-)

diff --git a/clang/include/clang/Tooling/DependencyScanning/ModuleDepCollector.h b/clang/include/clang/Tooling/DependencyScanning/ModuleDepCollector.h
index 081899cc2c8503..da51292296a90f 100644
--- a/clang/include/clang/Tooling/DependencyScanning/ModuleDepCollector.h
+++ b/clang/include/clang/Tooling/DependencyScanning/ModuleDepCollector.h
@@ -308,6 +308,11 @@ class ModuleDepCollector final : public DependencyCollector {
                                 ModuleDeps &Deps);
 };
 
+/// Resets codegen options that don't affect modules/PCH.
+void resetBenignCodeGenOptions(frontend::ActionKind ProgramAction,
+                               const LangOptions &LangOpts,
+                               CodeGenOptions &CGOpts);
+
 } // end namespace dependencies
 } // end namespace tooling
 } // end namespace clang
diff --git a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
index 94ccbd3351b09d..e19f19b2528c15 100644
--- a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
+++ b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
@@ -154,6 +154,26 @@ void ModuleDepCollector::addOutputPaths(CowCompilerInvocation &CI,
   }
 }
 
+void dependencies::resetBenignCodeGenOptions(frontend::ActionKind ProgramAction,
+                                             const LangOptions &LangOpts,
+                                             CodeGenOptions &CGOpts) {
+  // TODO: Figure out better way to set options to their default value.
+  if (ProgramAction == frontend::GenerateModule) {
+    CGOpts.MainFileName.clear();
+    CGOpts.DwarfDebugFlags.clear();
+  }
+  if (ProgramAction == frontend::GeneratePCH ||
+      (ProgramAction == frontend::GenerateModule && !LangOpts.ModulesCodegen)) {
+    CGOpts.DebugCompilationDir.clear();
+    CGOpts.CoverageCompilationDir.clear();
+    CGOpts.CoverageDataFile.clear();
+    CGOpts.CoverageNotesFile.clear();
+    CGOpts.ProfileInstrumentUsePath.clear();
+    CGOpts.SampleProfileFile.clear();
+    CGOpts.ProfileRemappingFile.clear();
+  }
+}
+
 static CowCompilerInvocation
 makeCommonInvocationForModuleBuild(CompilerInvocation CI) {
   CI.resetNonModularOptions();
@@ -167,18 +187,8 @@ makeCommonInvocationForModuleBuild(CompilerInvocation CI) {
   // LLVM options are not going to affect the AST
   CI.getFrontendOpts().LLVMArgs.clear();
 
-  // TODO: Figure out better way to set options to their default value.
-  CI.getCodeGenOpts().MainFileName.clear();
-  CI.getCodeGenOpts().DwarfDebugFlags.clear();
-  if (!CI.getLangOpts().ModulesCodegen) {
-    CI.getCodeGenOpts().DebugCompilationDir.clear();
-    CI.getCodeGenOpts().CoverageCompilationDir.clear();
-    CI.getCodeGenOpts().CoverageDataFile.clear();
-    CI.getCodeGenOpts().CoverageNotesFile.clear();
-    CI.getCodeGenOpts().ProfileInstrumentUsePath.clear();
-    CI.getCodeGenOpts().SampleProfileFile.clear();
-    CI.getCodeGenOpts().ProfileRemappingFile.clear();
-  }
+  resetBenignCodeGenOptions(frontend::GenerateModule, CI.getLangOpts(),
+                            CI.getCodeGenOpts());
 
   // Map output paths that affect behaviour to "-" so their existence is in the
   // context hash. The final path will be computed in addOutputPaths.
@@ -342,6 +352,8 @@ static bool needsModules(FrontendInputFile FIF) {
 
 void ModuleDepCollector::applyDiscoveredDependencies(CompilerInvocation &CI) {
   CI.clearImplicitModuleBuildOptions();
+  resetBenignCodeGenOptions(CI.getFrontendOpts().ProgramAction,
+                            CI.getLangOpts(), CI.getCodeGenOpts());
 
   if (llvm::any_of(CI.getFrontendOpts().Inputs, needsModules)) {
     Preprocessor &PP = ScanInstance.getPreprocessor();
diff --git a/clang/test/ClangScanDeps/removed-args.c b/clang/test/ClangScanDeps/removed-args.c
index f49e4ead82f7bf..3e108f0549450c 100644
--- a/clang/test/ClangScanDeps/removed-args.c
+++ b/clang/test/ClangScanDeps/removed-args.c
@@ -93,3 +93,31 @@
 // CHECK-NOT:          "-fmodules-prune-interval=
 // CHECK-NOT:          "-fmodules-prune-after=
 // CHECK:            ],
+
+// Check for removed args for PCH invocations.
+
+// RUN: split-file %s %t
+// RUN: sed "s|DIR|%/t|g" %t/cdb-pch.json.template > %t/cdb-pch.json
+// RUN: clang-scan-deps -compilation-database %t/cdb-pch.json -format experimental-full > %t/result-pch.json
+// RUN: cat %t/result-pch.json | sed 's:\\\\\?:/:g' | FileCheck %s -DPREFIX=%/t -check-prefix=PCH
+//
+// PCH-NOT:          "-fdebug-compilation-dir="
+// PCH-NOT:          "-fcoverage-compilation-dir="
+// PCH-NOT:          "-coverage-notes-file
+// PCH-NOT:          "-coverage-data-file
+// PCH-NOT:          "-fprofile-instrument-use-path
+// PCH-NOT:          "-include"
+// PCH-NOT:          "-fmodules-cache-path=
+// PCH-NOT:          "-fmodules-validate-once-per-build-session"
+// PCH-NOT:          "-fbuild-session-timestamp=
+// PCH-NOT:          "-fmodules-prune-interval=
+// PCH-NOT:          "-fmodules-prune-after=
+
+//--- cdb-pch.json.template
+[
+  {
+    "directory": "DIR",
+    "command": "clang -x c-header DIR/header.h -fmodules -fimplicit-module-maps -fmodules-cache-path=DIR/cache -fdebug-compilation-dir=DIR/debug -fcoverage-compilation-dir=DIR/coverage -ftest-coverage -fprofile-instr-use=DIR/tu.profdata -o DIR/header.h.pch -serialize-diagnostics DIR/header.h.pch.diag ",
+    "file": "DIR/header.h.pch"
+  }
+]