[NFC] Extract unifyTargetFeatures

Differential Revision: https://reviews.llvm.org/D82579

3 files changed, 37 insertions, 18 deletions

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index d908e00..8903641 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -374,25 +374,9 @@ static void getTargetFeatures(const Driver &D, const llvm::Triple &Triple,
     ve::getVETargetFeatures(D, Args, Features);
   }
 
-  // Find the last of each feature.
-  llvm::StringMap<unsigned> LastOpt;
-  for (unsigned I = 0, N = Features.size(); I < N; ++I) {
-    StringRef Name = Features[I];
-    assert(Name[0] == '-' || Name[0] == '+');
-    LastOpt[Name.drop_front(1)] = I;
-  }
-
-  for (unsigned I = 0, N = Features.size(); I < N; ++I) {
-    // If this feature was overridden, ignore it.
-    StringRef Name = Features[I];
-    llvm::StringMap<unsigned>::iterator LastI = LastOpt.find(Name.drop_front(1));
-    assert(LastI != LastOpt.end());
-    unsigned Last = LastI->second;
-    if (Last != I)
-      continue;
-
+  for (auto Feature : unifyTargetFeatures(Features)) {
     CmdArgs.push_back(IsAux ? "-aux-target-feature" : "-target-feature");
-    CmdArgs.push_back(Name.data());
+    CmdArgs.push_back(Feature.data());
   }
 }
 
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index 2a9d7e3..976db3f 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -84,6 +84,31 @@ void tools::handleTargetFeaturesGroup(const ArgList &Args,
   }
 }
 
+std::vector<StringRef>
+tools::unifyTargetFeatures(const std::vector<StringRef> &Features) {
+  std::vector<StringRef> UnifiedFeatures;
+  // Find the last of each feature.
+  llvm::StringMap<unsigned> LastOpt;
+  for (unsigned I = 0, N = Features.size(); I < N; ++I) {
+    StringRef Name = Features[I];
+    assert(Name[0] == '-' || Name[0] == '+');
+    LastOpt[Name.drop_front(1)] = I;
+  }
+
+  for (unsigned I = 0, N = Features.size(); I < N; ++I) {
+    // If this feature was overridden, ignore it.
+    StringRef Name = Features[I];
+    llvm::StringMap<unsigned>::iterator LastI = LastOpt.find(Name.drop_front(1));
+    assert(LastI != LastOpt.end());
+    unsigned Last = LastI->second;
+    if (Last != I)
+      continue;
+
+    UnifiedFeatures.push_back(Name);
+  }
+  return UnifiedFeatures;
+}
+
 void tools::addDirectoryList(const ArgList &Args, ArgStringList &CmdArgs,
                              const char *ArgName, const char *EnvVar) {
   const char *DirList = ::getenv(EnvVar);
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.h b/clang/lib/Driver/ToolChains/CommonArgs.h
index c7d695e..29dedec 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.h
+++ b/clang/lib/Driver/ToolChains/CommonArgs.h
@@ -106,10 +106,20 @@ void AddTargetFeature(const llvm::opt::ArgList &Args,
 std::string getCPUName(const llvm::opt::ArgList &Args, const llvm::Triple &T,
                        bool FromAs = false);
 
+/// Iterate \p Args and convert -mxxx to +xxx and -mno-xxx to -xxx and
+/// append it to \p Features.
+///
+/// Note: Since \p Features may contain default values before calling
+/// this function, or may be appended with entries to override arguments,
+/// entries in \p Features are not unique.
 void handleTargetFeaturesGroup(const llvm::opt::ArgList &Args,
                                std::vector<StringRef> &Features,
                                llvm::opt::OptSpecifier Group);
 
+/// If there are multiple +xxx or -xxx features, keep the last one.
+std::vector<StringRef>
+unifyTargetFeatures(const std::vector<StringRef> &Features);
+
 /// Handles the -save-stats option and returns the filename to save statistics
 /// to.
 SmallString<128> getStatsFileName(const llvm::opt::ArgList &Args,