Check pointer types for arguments of Neon load/store macros. rdar://9958031

The Neon load/store intrinsics need to be implemented as macros to avoid
hiding alignment attributes on the pointer arguments, and the macros can
only evaluate those pointer arguments once (in case they have side effects),
so it has been hard to get the right type checking for those pointers.
I tried various alternatives in the arm_neon.h header, but it's much more
straightforward to just check directly in Sema.

llvm-svn: 144075

3 files changed, 80 insertions, 13 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 90b97380398..cd07358b159 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -268,11 +268,38 @@ static unsigned RFT(unsigned t, bool shift = false) {
   return 0;
 }
 
+/// getNeonEltType - Return the QualType corresponding to the elements of
+/// the vector type specified by the NeonTypeFlags.  This is used to check
+/// the pointer arguments for Neon load/store intrinsics.
+static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context) {
+  switch (Flags.getEltType()) {
+  case NeonTypeFlags::Int8:
+    return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy;
+  case NeonTypeFlags::Int16:
+    return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy;
+  case NeonTypeFlags::Int32:
+    return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy;
+  case NeonTypeFlags::Int64:
+    return Flags.isUnsigned() ? Context.UnsignedLongLongTy : Context.LongLongTy;
+  case NeonTypeFlags::Poly8:
+    return Context.SignedCharTy;
+  case NeonTypeFlags::Poly16:
+    return Context.ShortTy;
+  case NeonTypeFlags::Float16:
+    return Context.UnsignedShortTy;
+  case NeonTypeFlags::Float32:
+    return Context.FloatTy;
+  }
+  return QualType();
+}
+
 bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
   llvm::APSInt Result;
 
   unsigned mask = 0;
   unsigned TV = 0;
+  bool HasPtr = false;
+  bool HasConstPtr = false;
   switch (BuiltinID) {
 #define GET_NEON_OVERLOAD_CHECK
 #include "clang/Basic/arm_neon.inc"
@@ -281,15 +308,39 @@ bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
   
   // For NEON intrinsics which are overloaded on vector element type, validate
   // the immediate which specifies which variant to emit.
+  unsigned ImmArg = TheCall->getNumArgs()-1;
   if (mask) {
-    unsigned ArgNo = TheCall->getNumArgs()-1;
-    if (SemaBuiltinConstantArg(TheCall, ArgNo, Result))
+    if (SemaBuiltinConstantArg(TheCall, ImmArg, Result))
       return true;
     
     TV = Result.getLimitedValue(64);
     if ((TV > 63) || (mask & (1 << TV)) == 0)
       return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code)
-        << TheCall->getArg(ArgNo)->getSourceRange();
+        << TheCall->getArg(ImmArg)->getSourceRange();
+  }
+
+  if (HasPtr || HasConstPtr) {
+    // Check that pointer arguments have the specified type.
+    for (unsigned ArgNo = 0; ArgNo < ImmArg; ++ArgNo) {
+      Expr *Arg = TheCall->getArg(ArgNo);
+      if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg))
+        Arg = ICE->getSubExpr();
+      ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg);
+      QualType RHSTy = RHS.get()->getType();
+      if (!RHSTy->isPointerType())
+        continue;
+      QualType EltTy = getNeonEltType(NeonTypeFlags(TV), Context);
+      if (HasConstPtr)
+        EltTy = EltTy.withConst();
+      QualType LHSTy = Context.getPointerType(EltTy);
+      AssignConvertType ConvTy;
+      ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS);
+      if (RHS.isInvalid())
+        return true;
+      if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy,
+                                   RHS.get(), AA_Assigning))
+        return true;
+    }
   }
   
   // For NEON intrinsics which take an immediate value as part of the 
diff --git a/clang/test/Sema/arm-neon-types.c b/clang/test/Sema/arm-neon-types.c
index 4be83da970b..7bb605d9b14 100644
--- a/clang/test/Sema/arm-neon-types.c
+++ b/clang/test/Sema/arm-neon-types.c
@@ -25,3 +25,11 @@ int32x4_t test4(int32x4_t a, vSInt32 b) {
   b += a;
   return b += a;
 }
+
+// Warn for incompatible pointer types used with vld/vst intrinsics.
+int16x8_t test5(int *p) {
+  return vld1q_s16(p); // expected-warning {{incompatible pointer types}}
+}
+void test6(float *p, int32x2_t v) {
+  return vst1_s32(p, v); // expected-warning {{incompatible pointer types}}
+}
diff --git a/clang/utils/TableGen/NeonEmitter.cpp b/clang/utils/TableGen/NeonEmitter.cpp
index f393dff6147..fec16b957ef 100644
--- a/clang/utils/TableGen/NeonEmitter.cpp
+++ b/clang/utils/TableGen/NeonEmitter.cpp
@@ -526,12 +526,6 @@ static std::string GenMacroLocals(const std::string &proto, StringRef typestr) {
   for (unsigned i = 1, e = proto.size(); i != e; ++i, ++arg) {
     // Do not create a temporary for an immediate argument.
     // That would defeat the whole point of using a macro!
-    // FIXME: For other (non-immediate) arguments that are used directly, a
-    // local temporary (or some other method) is still needed to get the
-    // correct type checking, even if that temporary is not used for anything.
-    // This is omitted for now because it turns out the the use of
-    // "__extension__" in the macro disables any warnings from the pointer
-    // assignment.
     if (MacroArgUsedDirectly(proto, i))
       continue;
     generatedLocal = true;
@@ -1342,14 +1336,28 @@ void NeonEmitter::runHeader(raw_ostream &OS) {
         mask |= 1 << GetNeonEnum(Proto, TypeVec[ti]);
       }
     }
-    if (mask)
+    bool HasPtr = (Proto.find('p') != std::string::npos);
+    bool HasConstPtr = (Proto.find('c') != std::string::npos);
+    if (mask) {
       OS << "case ARM::BI__builtin_neon_"
          << MangleName(name, TypeVec[si], ClassB)
-         << ": mask = " << "0x" << utohexstr(mask) << "; break;\n";
-    if (qmask)
+         << ": mask = " << "0x" << utohexstr(mask);
+      if (HasPtr)
+        OS << "; HasPtr = true";
+      if (HasConstPtr)
+        OS << "; HasConstPtr = true";
+      OS << "; break;\n";
+    }
+    if (qmask) {
       OS << "case ARM::BI__builtin_neon_"
          << MangleName(name, TypeVec[qi], ClassB)
-         << ": mask = " << "0x" << utohexstr(qmask) << "; break;\n";
+         << ": mask = " << "0x" << utohexstr(qmask);
+      if (HasPtr)
+        OS << "; HasPtr = true";
+      if (HasConstPtr)
+        OS << "; HasConstPtr = true";
+      OS << "; break;\n";
+    }
   }
   OS << "#endif\n\n";