[OpenCL] Add generic type handling for builtin functions

Generic types are an abstraction of type sets.  It mimics the way
functions are defined in the OpenCL specification.  For example,
floatN can abstract all the vector sizes of the float type.

This allows to
 * stick more closely to the specification, which uses generic types;
 * factorize definitions of functions with numerous prototypes in the
   tablegen file; and
 * reduce the memory impact of functions with many overloads.

Patch by Pierre Gondois and Sven van Haastregt.

Differential Revision: https://reviews.llvm.org/D65456

llvm-svn: 369253

1 files changed, 131 insertions, 58 deletions

diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index 5127ce026c8..525f921b297 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -673,76 +673,148 @@ LLVM_DUMP_METHOD void LookupResult::dump() {
     D->dump();
 }
 
-/// When trying to resolve a function name, if the isOpenCLBuiltin function
-/// defined in "OpenCLBuiltins.inc" returns a non-null <Index, Len>, then the
-/// identifier is referencing an OpenCL builtin function. Thus, all its
-/// prototypes are added to the LookUpResult.
-///
-/// \param S The Sema instance
-/// \param LR  The LookupResult instance
-/// \param II  The identifier being resolved
-/// \param Index  The list of prototypes starts at Index in OpenCLBuiltins[]
-/// \param Len  The list of prototypes has Len elements
-static void InsertOCLBuiltinDeclarations(Sema &S, LookupResult &LR,
-                                         IdentifierInfo *II, unsigned Index,
-                                         unsigned Len) {
-
-  for (unsigned i = 0; i < Len; ++i) {
-    const OpenCLBuiltinDecl &Decl = OpenCLBuiltins[Index - 1 + i];
-    ASTContext &Context = S.Context;
+/// Get the QualType instances of the return type and arguments for an OpenCL
+/// builtin function signature.
+/// \param Context (in) The Context instance.
+/// \param OpenCLBuiltin (in) The signature currently handled.
+/// \param GenTypeMaxCnt (out) Maximum number of types contained in a generic
+///        type used as return type or as argument.
+///        Only meaningful for generic types, otherwise equals 1.
+/// \param RetTypes (out) List of the possible return types.
+/// \param ArgTypes (out) List of the possible argument types.  For each
+///        argument, ArgTypes contains QualTypes for the Cartesian product
+///        of (vector sizes) x (types) .
+static void GetQualTypesForOpenCLBuiltin(
+    ASTContext &Context, const OpenCLBuiltinStruct &OpenCLBuiltin,
+    unsigned &GenTypeMaxCnt, std::vector<QualType> &RetTypes,
+    SmallVector<std::vector<QualType>, 5> &ArgTypes) {
+  // Get the QualType instances of the return types.
+  unsigned Sig = SignatureTable[OpenCLBuiltin.SigTableIndex];
+  OCL2Qual(Context, TypeTable[Sig], RetTypes);
+  GenTypeMaxCnt = RetTypes.size();
+
+  // Get the QualType instances of the arguments.
+  // First type is the return type, skip it.
+  for (unsigned Index = 1; Index < OpenCLBuiltin.NumTypes; Index++) {
+    std::vector<QualType> Ty;
+    OCL2Qual(Context,
+        TypeTable[SignatureTable[OpenCLBuiltin.SigTableIndex + Index]], Ty);
+    ArgTypes.push_back(Ty);
+    GenTypeMaxCnt = (Ty.size() > GenTypeMaxCnt) ? Ty.size() : GenTypeMaxCnt;
+  }
+}
 
-    // Ignore this BIF if the version is incorrect.
-    if (Context.getLangOpts().OpenCLVersion < Decl.Version)
-      continue;
+/// Create a list of the candidate function overloads for an OpenCL builtin
+/// function.
+/// \param Context (in) The ASTContext instance.
+/// \param GenTypeMaxCnt (in) Maximum number of types contained in a generic
+///        type used as return type or as argument.
+///        Only meaningful for generic types, otherwise equals 1.
+/// \param FunctionList (out) List of FunctionTypes.
+/// \param RetTypes (in) List of the possible return types.
+/// \param ArgTypes (in) List of the possible types for the arguments.
+static void
+GetOpenCLBuiltinFctOverloads(ASTContext &Context, unsigned GenTypeMaxCnt,
+                             std::vector<QualType> &FunctionList,
+                             std::vector<QualType> &RetTypes,
+                             SmallVector<std::vector<QualType>, 5> &ArgTypes) {
+  FunctionProtoType::ExtProtoInfo PI;
+  PI.Variadic = false;
+
+  // Create FunctionTypes for each (gen)type.
+  for (unsigned IGenType = 0; IGenType < GenTypeMaxCnt; IGenType++) {
+    SmallVector<QualType, 5> ArgList;
+
+    for (unsigned A = 0; A < ArgTypes.size(); A++) {
+      // Builtins such as "max" have an "sgentype" argument that represents
+      // the corresponding scalar type of a gentype.  The number of gentypes
+      // must be a multiple of the number of sgentypes.
+      assert(GenTypeMaxCnt % ArgTypes[A].size() == 0 &&
+             "argument type count not compatible with gentype type count");
+      unsigned Idx = IGenType % ArgTypes[A].size();
+      ArgList.push_back(ArgTypes[A][Idx]);
+    }
 
-    FunctionProtoType::ExtProtoInfo PI;
-    PI.Variadic = false;
+    FunctionList.push_back(Context.getFunctionType(
+        RetTypes[(RetTypes.size() != 1) ? IGenType : 0], ArgList, PI));
+  }
+}
 
-    // Defined in "OpenCLBuiltins.inc"
-    QualType RT = OCL2Qual(Context, OpenCLSignature[Decl.ArgTableIndex]);
+/// When trying to resolve a function name, if isOpenCLBuiltin() returns a
+/// non-null <Index, Len> pair, then the name is referencing an OpenCL
+/// builtin function.  Add all candidate signatures to the LookUpResult.
+///
+/// \param S (in) The Sema instance.
+/// \param LR (inout) The LookupResult instance.
+/// \param II (in) The identifier being resolved.
+/// \param FctIndex (in) Starting index in the BuiltinTable.
+/// \param Len (in) The signature list has Len elements.
+static void InsertOCLBuiltinDeclarationsFromTable(Sema &S, LookupResult &LR,
+                                                  IdentifierInfo *II,
+                                                  const unsigned FctIndex,
+                                                  const unsigned Len) {
+  // The builtin function declaration uses generic types (gentype).
+  bool HasGenType = false;
+
+  // Maximum number of types contained in a generic type used as return type or
+  // as argument.  Only meaningful for generic types, otherwise equals 1.
+  unsigned GenTypeMaxCnt;
+
+  for (unsigned SignatureIndex = 0; SignatureIndex < Len; SignatureIndex++) {
+    const OpenCLBuiltinStruct &OpenCLBuiltin =
+        BuiltinTable[FctIndex + SignatureIndex];
+    ASTContext &Context = S.Context;
+
+    std::vector<QualType> RetTypes;
+    SmallVector<std::vector<QualType>, 5> ArgTypes;
 
-    SmallVector<QualType, 5> ArgTypes;
-    for (unsigned I = 1; I < Decl.NumArgs; I++) {
-      QualType Ty = OCL2Qual(Context, OpenCLSignature[Decl.ArgTableIndex + I]);
-      ArgTypes.push_back(Ty);
+    // Obtain QualType lists for the function signature.
+    GetQualTypesForOpenCLBuiltin(Context, OpenCLBuiltin, GenTypeMaxCnt,
+                                 RetTypes, ArgTypes);
+    if (GenTypeMaxCnt > 1) {
+      HasGenType = true;
     }
 
-    QualType R = Context.getFunctionType(RT, ArgTypes, PI);
-    SourceLocation Loc = LR.getNameLoc();
+    // Create function overload for each type combination.
+    std::vector<QualType> FunctionList;
+    GetOpenCLBuiltinFctOverloads(Context, GenTypeMaxCnt, FunctionList, RetTypes,
+                                 ArgTypes);
 
-    // TODO: This part is taken from Sema::LazilyCreateBuiltin,
-    // maybe refactor it.
+    SourceLocation Loc = LR.getNameLoc();
     DeclContext *Parent = Context.getTranslationUnitDecl();
-    FunctionDecl *New = FunctionDecl::Create(Context, Parent, Loc, Loc, II, R,
-                                             /*TInfo=*/nullptr, SC_Extern,
-                                             false, R->isFunctionProtoType());
-    New->setImplicit();
-
-    // Create Decl objects for each parameter, adding them to the
-    // FunctionDecl.
-    if (const FunctionProtoType *FT = dyn_cast<FunctionProtoType>(R)) {
-      SmallVector<ParmVarDecl *, 16> Params;
-      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
-        ParmVarDecl *Parm =
-            ParmVarDecl::Create(Context, New, SourceLocation(),
-                                SourceLocation(), nullptr, FT->getParamType(i),
-                                /*TInfo=*/nullptr, SC_None, nullptr);
-        Parm->setScopeInfo(0, i);
-        Params.push_back(Parm);
+    FunctionDecl *NewOpenCLBuiltin;
+
+    for (unsigned Index = 0; Index < GenTypeMaxCnt; Index++) {
+      NewOpenCLBuiltin = FunctionDecl::Create(
+          Context, Parent, Loc, Loc, II, FunctionList[Index],
+          /*TInfo=*/nullptr, SC_Extern, false,
+          FunctionList[Index]->isFunctionProtoType());
+      NewOpenCLBuiltin->setImplicit();
+
+      // Create Decl objects for each parameter, adding them to the
+      // FunctionDecl.
+      if (const FunctionProtoType *FP =
+              dyn_cast<FunctionProtoType>(FunctionList[Index])) {
+        SmallVector<ParmVarDecl *, 16> ParmList;
+        for (unsigned IParm = 0, e = FP->getNumParams(); IParm != e; ++IParm) {
+          ParmVarDecl *Parm = ParmVarDecl::Create(
+              Context, NewOpenCLBuiltin, SourceLocation(), SourceLocation(),
+              nullptr, FP->getParamType(IParm),
+              /*TInfo=*/nullptr, SC_None, nullptr);
+          Parm->setScopeInfo(0, IParm);
+          ParmList.push_back(Parm);
+        }
+        NewOpenCLBuiltin->setParams(ParmList);
       }
-      New->setParams(Params);
+      if (!S.getLangOpts().OpenCLCPlusPlus) {
+        NewOpenCLBuiltin->addAttr(OverloadableAttr::CreateImplicit(Context));
+      }
+      LR.addDecl(NewOpenCLBuiltin);
     }
-
-    New->addAttr(OverloadableAttr::CreateImplicit(Context));
-
-    if (strlen(Decl.Extension))
-      S.setOpenCLExtensionForDecl(New, Decl.Extension);
-
-    LR.addDecl(New);
   }
 
   // If we added overloads, need to resolve the lookup result.
-  if (Len > 1)
+  if (Len > 1 || HasGenType)
     LR.resolveKind();
 }
 
@@ -772,7 +844,8 @@ static bool LookupBuiltin(Sema &S, LookupResult &R) {
       if (S.getLangOpts().OpenCL && S.getLangOpts().DeclareOpenCLBuiltins) {
         auto Index = isOpenCLBuiltin(II->getName());
         if (Index.first) {
-          InsertOCLBuiltinDeclarations(S, R, II, Index.first, Index.second);
+          InsertOCLBuiltinDeclarationsFromTable(S, R, II, Index.first - 1,
+                                                Index.second);
           return true;
         }
       }