[SYCL] Filter out the header and footer from the dependency output. (#14933)

`Cmake` uses dependency information generated by the use of the` -MD`
option to decide if a file needs to be rebuilt. Currently the header and
footer are not filtered out from the dependency output. This leads to
the issue that `Cmake` thinks the source file needs to always be
rebuilt.
This is a patch to fix the issue.
See #14798 for more details.

Author: zahiraam

clang/include/clang/Driver/Options.td

@@ -7696,7 +7696,7 @@ def show_includes : Flag<["--"], "show-includes">,
   HelpText<"Print cl.exe style /showIncludes to stdout">;
 def dependency_filter : Separate<["-"], "dependency-filter">,
   HelpText<"Filter dependencies with prefix from the dependency output.">,
-  MarshallingInfoString<DependencyOutputOpts<"DependencyFilter">>;
+  MarshallingInfoStringVector<DependencyOutputOpts<"DependencyFilter">>;
 
 } // let Visibility = [CC1Option]
 

clang/include/clang/Frontend/DependencyOutputOptions.h

@@ -87,8 +87,8 @@ class DependencyOutputOptions {
   std::string ModuleDependencyOutputDir;
 
   /// Dependency output which is prefixed with this string is filtered from
-  /// the dependency output. 
-  std::string DependencyFilter;
+  /// the dependency output.
+  std::vector<std::string> DependencyFilter;
 
 public:
   DependencyOutputOptions()

clang/include/clang/Frontend/Utils.h

@@ -121,7 +121,7 @@ class DependencyFileGenerator : public DependencyCollector {
   void outputDependencyFile(DiagnosticsEngine &Diags);
 
   std::string OutputFile;
-  std::string DependencyFilter;
+  std::vector<std::string> DependencyFilter;
   std::vector<std::string> Targets;
   bool IncludeSystemHeaders;
   bool PhonyTarget;

clang/lib/Frontend/DependencyFile.cpp

@@ -255,11 +255,10 @@ bool DependencyFileGenerator::sawDependency(StringRef Filename, bool FromModule,
   if (isSpecialFilename(Filename))
     return false;
 
-  if (DependencyFilter.size() &&
-      DependencyFilter.compare(0, DependencyFilter.size(), Filename.data(),
-                               DependencyFilter.size()) == 0)
-    // Remove dependencies that are prefixed by the Filter string.
-    return false;
+  // Remove dependencies that are prefixed by the Filter string.
+  for (const std::string &FD : DependencyFilter)
+    if (FD.compare(0, FD.size(), Filename.data(), FD.size()) == 0)
+      return false;
 
   if (IncludeSystemHeaders)
     return true;

clang/test/Frontend/Inputs/dependency.cpp

@@ -0,0 +1,3 @@
+int dep() {
+  return 0;
+}

clang/test/Frontend/dependency-gen.c

@@ -47,3 +47,11 @@
 // RUN: %clang -MMD -MF - %s -fsyntax-only -resource-dir=%S/Inputs/resource_dir_with_sanitizer_ignorelist -fsanitize=undefined -flto -fvisibility=hidden -I ./ | FileCheck -check-prefix=ONLY-USER-DEPS %s
 // ONLY-USER-DEPS: dependency-gen.o:
 // NOT-ONLY-USER-DEPS: ubsan_ignorelist.txt
+
+// RUN: %clang -c -x c++ -fsycl \
+// RUN: -MD -MF - %S/Inputs/dependency.cpp | FileCheck -check-prefix=FILTER %s
+
+// FILTER: dependency.o:
+// FILTER: {{.*}}dependency.cpp
+// FILTER: dependency.o:
+// FILTER: {{.*}}dependency.cpp