1 files changed, 71 insertions, 0 deletions
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 4710130..2616226 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -4688,6 +4688,77 @@ private:
   llvm::Value *FormResolverCondition(const MultiVersionResolverOption &RO);
 };
 
+/// TargetFeatures - This class is used to check whether the builtin function
+/// has the required tagert specific features. It is able to support the
+/// combination of ','(and), '|'(or), and '()'. By default, the priority of
+/// ',' is higher than that of '|' .
+/// E.g:
+/// A,B|C means the builtin function requires both A and B, or C.
+/// If we want the builtin function requires both A and B, or both A and C,
+/// there are two ways: A,B|A,C or A,(B|C).
+/// The FeaturesList should not contain spaces, and brackets must appear in
+/// pairs.
+class TargetFeatures {
+  struct FeatureListStatus {
+    bool HasFeatures;
+    StringRef CurFeaturesList;
+  };
+
+  const llvm::StringMap<bool> &CallerFeatureMap;
+
+  FeatureListStatus getAndFeatures(StringRef FeatureList) {
+    int InParentheses = 0;
+    bool HasFeatures = true;
+    size_t SubexpressionStart = 0;
+    for (size_t i = 0, e = FeatureList.size(); i < e; ++i) {
+      char CurrentToken = FeatureList[i];
+      switch (CurrentToken) {
+      default:
+        break;
+      case '(':
+        if (InParentheses == 0)
+          SubexpressionStart = i + 1;
+        ++InParentheses;
+        break;
+      case ')':
+        --InParentheses;
+        assert(InParentheses >= 0 && "Parentheses are not in pair");
+        LLVM_FALLTHROUGH;
+      case '|':
+      case ',':
+        if (InParentheses == 0) {
+          if (HasFeatures && i != SubexpressionStart) {
+            StringRef F = FeatureList.slice(SubexpressionStart, i);
+            HasFeatures = CurrentToken == ')' ? hasRequiredFeatures(F)
+                                              : CallerFeatureMap.lookup(F);
+          }
+          SubexpressionStart = i + 1;
+          if (CurrentToken == '|') {
+            return {HasFeatures, FeatureList.substr(SubexpressionStart)};
+          }
+        }
+        break;
+      }
+    }
+    assert(InParentheses == 0 && "Parentheses are not in pair");
+    if (HasFeatures && SubexpressionStart != FeatureList.size())
+      HasFeatures =
+          CallerFeatureMap.lookup(FeatureList.substr(SubexpressionStart));
+    return {HasFeatures, StringRef()};
+  }
+
+public:
+  bool hasRequiredFeatures(StringRef FeatureList) {
+    FeatureListStatus FS = {false, FeatureList};
+    while (!FS.HasFeatures && !FS.CurFeaturesList.empty())
+      FS = getAndFeatures(FS.CurFeaturesList);
+    return FS.HasFeatures;
+  }
+
+  TargetFeatures(const llvm::StringMap<bool> &CallerFeatureMap)
+      : CallerFeatureMap(CallerFeatureMap) {}
+};
+
 inline DominatingLLVMValue::saved_type
 DominatingLLVMValue::save(CodeGenFunction &CGF, llvm::Value *value) {
   if (!needsSaving(value)) return saved_type(value, false);