[libclang] Restore the CXXRecordDecl path for clang_Type_getNumTemplateArguments and clang_Type_getTemplateArgumentAsType

Patch by Emilio Cobos Álvarez!
See https://reviews.llvm.org/D26907

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@289995 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 80 insertions, 30 deletions

diff --git a/tools/c-index-test/c-index-test.c b/tools/c-index-test/c-index-test.c
index de87351059..dfb4b27bce 100644
--- a/tools/c-index-test/c-index-test.c
+++ b/tools/c-index-test/c-index-test.c
@@ -1316,6 +1316,25 @@ static enum CXVisitorResult FieldVisitor(CXCursor C,
     return CXVisit_Continue;
 }
 
+static void PrintTypeTemplateArgs(CXType T, const char *Format) {
+  int NumTArgs = clang_Type_getNumTemplateArguments(T);
+  if (NumTArgs != -1 && NumTArgs != 0) {
+    int i;
+    CXType TArg;
+    printf(Format, NumTArgs);
+    for (i = 0; i < NumTArgs; ++i) {
+      TArg = clang_Type_getTemplateArgumentAsType(T, i);
+      if (TArg.kind != CXType_Invalid) {
+        PrintTypeAndTypeKind(TArg, " [type=%s] [typekind=%s]");
+      }
+    }
+    /* Ensure that the returned type is invalid when indexing off-by-one. */
+    TArg = clang_Type_getTemplateArgumentAsType(T, i);
+    assert(TArg.kind == CXType_Invalid);
+    printf("]");
+  }
+}
+
 static enum CXChildVisitResult PrintType(CXCursor cursor, CXCursor p,
                                          CXClientData d) {
   if (!clang_isInvalid(clang_getCursorKind(cursor))) {
@@ -1333,11 +1352,14 @@ static enum CXChildVisitResult PrintType(CXCursor cursor, CXCursor p,
       printf(" lvalue-ref-qualifier");
     if (RQ == CXRefQualifier_RValue)
       printf(" rvalue-ref-qualifier");
+    /* Print the template argument types if they exist. */
+    PrintTypeTemplateArgs(T, " [templateargs/%d=");
     /* Print the canonical type if it is different. */
     {
       CXType CT = clang_getCanonicalType(T);
       if (!clang_equalTypes(T, CT)) {
         PrintTypeAndTypeKind(CT, " [canonicaltype=%s] [canonicaltypekind=%s]");
+        PrintTypeTemplateArgs(CT, " [canonicaltemplateargs/%d=");
       }
     }
     /* Print the return type if it exists. */
@@ -1362,21 +1384,6 @@ static enum CXChildVisitResult PrintType(CXCursor cursor, CXCursor p,
         printf("]");
       }
     }
-    /* Print the template argument types if they exist. */
-    {
-      int NumTArgs = clang_Type_getNumTemplateArguments(T);
-      if (NumTArgs != -1 && NumTArgs != 0) {
-        int i;
-        printf(" [templateargs/%d=", NumTArgs);
-        for (i = 0; i < NumTArgs; ++i) {
-          CXType TArg = clang_Type_getTemplateArgumentAsType(T, i);
-          if (TArg.kind != CXType_Invalid) {
-            PrintTypeAndTypeKind(TArg, " [type=%s] [typekind=%s]");
-          }
-        }
-        printf("]");
-      }
-    }
     /* Print if this is a non-POD type. */
     printf(" [isPOD=%d]", clang_isPODType(T));
     /* Print the pointee type. */
diff --git a/tools/libclang/CXType.cpp b/tools/libclang/CXType.cpp
index a07bbe0857..22269984c1 100644
--- a/tools/libclang/CXType.cpp
+++ b/tools/libclang/CXType.cpp
@@ -920,33 +920,76 @@ CXString clang_getDeclObjCTypeEncoding(CXCursor C) {
   return cxstring::createDup(encoding);
 }
 
+static Optional<ArrayRef<TemplateArgument>>
+GetTemplateArguments(QualType Type) {
+  assert(!Type.isNull());
+  if (const auto *Specialization = Type->getAs<TemplateSpecializationType>())
+    return Specialization->template_arguments();
+
+  if (const auto *RecordDecl = Type->getAsCXXRecordDecl()) {
+    const auto *TemplateDecl =
+      dyn_cast<ClassTemplateSpecializationDecl>(RecordDecl);
+    if (TemplateDecl)
+      return TemplateDecl->getTemplateArgs().asArray();
+  }
+
+  return None;
+}
+
+static unsigned GetTemplateArgumentArraySize(ArrayRef<TemplateArgument> TA) {
+  unsigned size = TA.size();
+  for (const auto &Arg : TA)
+    if (Arg.getKind() == TemplateArgument::Pack)
+      size += Arg.pack_size() - 1;
+  return size;
+}
+
 int clang_Type_getNumTemplateArguments(CXType CT) {
   QualType T = GetQualType(CT);
   if (T.isNull())
     return -1;
-  const TemplateSpecializationType *Specialization =
-    T->getAs<TemplateSpecializationType>();
-  if (!Specialization)
+
+  auto TA = GetTemplateArguments(T);
+  if (!TA)
     return -1;
-  return Specialization->template_arguments().size();
+
+  return GetTemplateArgumentArraySize(TA.getValue());
 }
 
-CXType clang_Type_getTemplateArgumentAsType(CXType CT, unsigned i) {
+static Optional<QualType> TemplateArgumentToQualType(const TemplateArgument &A) {
+  if (A.getKind() == TemplateArgument::Type)
+    return A.getAsType();
+  return None;
+}
+
+static Optional<QualType>
+FindTemplateArgumentTypeAt(ArrayRef<TemplateArgument> TA, unsigned index) {
+  unsigned current = 0;
+  for (const auto &A : TA) {
+    if (A.getKind() == TemplateArgument::Pack) {
+      if (index < current + A.pack_size())
+        return TemplateArgumentToQualType(A.getPackAsArray()[index - current]);
+      current += A.pack_size();
+      continue;
+    }
+    if (current == index)
+      return TemplateArgumentToQualType(A);
+    current++;
+  }
+  return None;
+}
+
+CXType clang_Type_getTemplateArgumentAsType(CXType CT, unsigned index) {
   QualType T = GetQualType(CT);
   if (T.isNull())
     return MakeCXType(QualType(), GetTU(CT));
 
-  const TemplateSpecializationType *Specialization =
-    T->getAs<TemplateSpecializationType>();
-  if (!Specialization)
-    return MakeCXType(QualType(), GetTU(CT));
-  auto TA = Specialization->template_arguments();
-  if (TA.size() <= i)
+  auto TA = GetTemplateArguments(T);
+  if (!TA)
     return MakeCXType(QualType(), GetTU(CT));
-  const TemplateArgument &A = TA[i];
-  if (A.getKind() != TemplateArgument::Type)
-    return MakeCXType(QualType(), GetTU(CT));
-  return MakeCXType(A.getAsType(), GetTU(CT));
+
+  Optional<QualType> QT = FindTemplateArgumentTypeAt(TA.getValue(), index);
+  return MakeCXType(QT.getValueOr(QualType()), GetTU(CT));
 }
 
 unsigned clang_Type_visitFields(CXType PT,