[clang] Remove duplication in types::getCompilationPhases()

Call Driver::getFinalPhase() instead of duplicating it.

https://reviews.llvm.org/D65993 added the duplication, then
02e35832c3 maded it more obviously a copy of getFinalPhase().

The only difference is that getCompilationPhases() used to use
LastPhase / IfsMerge where getFinalPhase() used Link. Adapt
getFinalPhase() to return IfsMerge when needed.

No intentional behavior change.

Differential Revision: https://reviews.llvm.org/D110770

clang/include/clang/Driver/Driver.h

@@ -253,6 +253,14 @@ public:
   /// or when using the -gen-reproducer driver flag.
   unsigned GenReproducer : 1;
 
+  // getFinalPhase - Determine which compilation mode we are in and record
+  // which option we used to determine the final phase.
+  // TODO: Much of what getFinalPhase returns are not actually true compiler
+  //       modes. Fold this functionality into Types::getCompilationPhases and
+  //       handleArguments.
+  phases::ID getFinalPhase(const llvm::opt::DerivedArgList &DAL,
+                           llvm::opt::Arg **FinalPhaseArg = nullptr) const;
+
 private:
   /// Certain options suppress the 'no input files' warning.
   unsigned SuppressMissingInputWarning : 1;
@@ -270,14 +278,6 @@ private:
   llvm::opt::DerivedArgList *
   TranslateInputArgs(const llvm::opt::InputArgList &Args) const;
 
-  // getFinalPhase - Determine which compilation mode we are in and record
-  // which option we used to determine the final phase.
-  // TODO: Much of what getFinalPhase returns are not actually true compiler
-  //       modes. Fold this functionality into Types::getCompilationPhases and
-  //       handleArguments.
-  phases::ID getFinalPhase(const llvm::opt::DerivedArgList &DAL,
-                           llvm::opt::Arg **FinalPhaseArg = nullptr) const;
-
   // handleArguments - All code related to claiming and printing diagnostics
   // related to arguments to the driver are done here.
   void handleArguments(Compilation &C, llvm::opt::DerivedArgList &Args,

clang/include/clang/Driver/Phases.h

@@ -22,11 +22,10 @@ namespace phases {
     Assemble,
     Link,
     IfsMerge,
-    LastPhase = IfsMerge,
   };
 
   enum {
-    MaxNumberOfPhases = LastPhase + 1
+    MaxNumberOfPhases = IfsMerge + 1
   };
 
   const char *getPhaseName(ID Id);

clang/include/clang/Driver/Types.h

@@ -111,7 +111,7 @@ namespace types {
   /// getCompilationPhases - Get the list of compilation phases ('Phases') to be
   /// done for type 'Id' up until including LastPhase.
   llvm::SmallVector<phases::ID, phases::MaxNumberOfPhases>
-  getCompilationPhases(ID Id, phases::ID LastPhase = phases::LastPhase);
+  getCompilationPhases(ID Id, phases::ID LastPhase = phases::IfsMerge);
   llvm::SmallVector<phases::ID, phases::MaxNumberOfPhases>
   getCompilationPhases(const clang::driver::Driver &Driver,
                        llvm::opt::DerivedArgList &DAL, ID Id);

clang/lib/Driver/Driver.cpp

@@ -304,6 +304,9 @@ phases::ID Driver::getFinalPhase(const DerivedArgList &DAL,
   } else if ((PhaseArg = DAL.getLastArg(options::OPT_c))) {
     FinalPhase = phases::Assemble;
 
+  } else if ((PhaseArg = DAL.getLastArg(options::OPT_emit_interface_stubs))) {
+    FinalPhase = phases::IfsMerge;
+
   // Otherwise do everything.
   } else
     FinalPhase = phases::Link;
@@ -3841,7 +3844,7 @@ void Driver::BuildActions(Compilation &C, DerivedArgList &Args,
   if (Args.hasArg(options::OPT_emit_interface_stubs)) {
     auto PhaseList = types::getCompilationPhases(
         types::TY_IFS_CPP,
-        Args.hasArg(options::OPT_c) ? phases::Compile : phases::LastPhase);
+        Args.hasArg(options::OPT_c) ? phases::Compile : phases::IfsMerge);
 
     ActionList MergerInputs;
 

clang/lib/Driver/Types.cpp

@@ -362,46 +362,7 @@ types::getCompilationPhases(ID Id, phases::ID LastPhase) {
 llvm::SmallVector<phases::ID, phases::MaxNumberOfPhases>
 types::getCompilationPhases(const clang::driver::Driver &Driver,
                             llvm::opt::DerivedArgList &DAL, ID Id) {
-  phases::ID LastPhase;
-
-  // Filter to compiler mode. When the compiler is run as a preprocessor then
-  // compilation is not an option.
-  // -S runs the compiler in Assembly listing mode.
-  if (Driver.CCCIsCPP() || DAL.getLastArg(options::OPT_E) ||
-      DAL.getLastArg(options::OPT__SLASH_EP) ||
-      DAL.getLastArg(options::OPT_M, options::OPT_MM) ||
-      DAL.getLastArg(options::OPT__SLASH_P))
-    LastPhase = phases::Preprocess;
-
-  // --precompile only runs up to precompilation.
-  // This is a clang extension and is not compatible with GCC.
-  else if (DAL.getLastArg(options::OPT__precompile))
-    LastPhase = phases::Precompile;
-
-  // -{fsyntax-only,-analyze,emit-ast} only run up to the compiler.
-  else if (DAL.getLastArg(options::OPT_fsyntax_only) ||
-           DAL.getLastArg(options::OPT_print_supported_cpus) ||
-           DAL.getLastArg(options::OPT_module_file_info) ||
-           DAL.getLastArg(options::OPT_verify_pch) ||
-           DAL.getLastArg(options::OPT_rewrite_objc) ||
-           DAL.getLastArg(options::OPT_rewrite_legacy_objc) ||
-           DAL.getLastArg(options::OPT__migrate) ||
-           DAL.getLastArg(options::OPT__analyze) ||
-           DAL.getLastArg(options::OPT_emit_ast))
-    LastPhase = phases::Compile;
-
-  else if (DAL.getLastArg(options::OPT_S) ||
-           DAL.getLastArg(options::OPT_emit_llvm))
-    LastPhase = phases::Backend;
-
-  else if (DAL.getLastArg(options::OPT_c))
-    LastPhase = phases::Assemble;
-
-  // Generally means, do every phase until Link.
-  else
-    LastPhase = phases::LastPhase;
-
-  return types::getCompilationPhases(Id, LastPhase);
+  return types::getCompilationPhases(Id, Driver.getFinalPhase(DAL));
 }
 
 ID types::lookupCXXTypeForCType(ID Id) {