__declspec support for function declarations.

safe: indicates that the function can safely be called with an "all off"
execution mask.

costN: (N an integer) overrides the cost estimate for the function with
the given value.

ast.cpp

@@ -323,15 +323,23 @@ static bool
 lCheckAllOffSafety(ASTNode *node, void *data) {
     bool *okPtr = (bool *)data;
 
-    if (dynamic_cast<FunctionCallExpr *>(node) != NULL) {
-        // FIXME: If we could somehow determine that the function being
-        // called was safe (and all of the args Exprs were safe, then it'd
-        // be nice to be able to return true here.  (Consider a call to
-        // e.g. floatbits() in the stdlib.)  Unfortunately for now we just
-        // have to be conservative.
+    FunctionCallExpr *fce;
+    if ((fce = dynamic_cast<FunctionCallExpr *>(node)) != NULL) {
+        if (fce->func == NULL)
+            return false;
+
+        const Type *type = fce->func->GetType();
+        const PointerType *pt = dynamic_cast<const PointerType *>(type);
+        if (pt != NULL)
+            type = pt->GetBaseType();
+        const FunctionType *ftype = dynamic_cast<const FunctionType *>(type);
+        Assert(ftype != NULL);
+
+        if (ftype->isSafe == false) {
             *okPtr = false;
             return false;
         }
+    }
 
     if (dynamic_cast<AssertStmt *>(node) != NULL) {
         // While it's fine to run the assert for varying tests, it's not

decl.cpp

@@ -538,10 +538,31 @@ Declarator::GetType(const Type *base, DeclSpecs *ds) const {
             return NULL;
         }
 
-        const Type *functionType = 
+        const FunctionType *functionType = 
             new FunctionType(returnType, args, argNames, argDefaults,
                              argPos, isTask, isExported, isExternC);
         functionType = functionType->ResolveUnboundVariability(Variability::Varying);
+
+        // handle any explicit __declspecs on the function
+        if (ds != NULL) {
+            for (int i = 0; i < (int)ds->declSpecList.size(); ++i) {
+                std::string str = ds->declSpecList[i].first;
+                SourcePos pos = ds->declSpecList[i].second;
+
+                if (str == "safe")
+                    (const_cast<FunctionType *>(functionType))->isSafe = true;
+                else if (!strncmp(str.c_str(), "cost", 4)) {
+                    int cost = atoi(str.c_str() + 4);
+                    if (cost < 0)
+                        Error(pos, "Negative function cost %d is illegal.",
+                              cost);
+                    (const_cast<FunctionType *>(functionType))->costOverride = cost;
+                }
+                else
+                    Error(pos, "__declspec parameter \"%s\" unknown.", str.c_str());
+            }
+        }
+
         return child->GetType(functionType, ds);
     }
     default:
@@ -555,6 +576,14 @@ const Type *
 Declarator::GetType(DeclSpecs *ds) const {
     const Type *baseType = ds->GetBaseType(pos);
     const Type *type = GetType(baseType, ds);
+
+    if (ds->declSpecList.size() > 0 && 
+        type != NULL &
+        dynamic_cast<const FunctionType *>(type) == NULL) {
+        Error(pos, "__declspec specifiers for non-function type \"%s\" are "
+              "not used.", type->GetString().c_str());
+    }
+
     return type;
 }
 

expr.cpp

@@ -3518,17 +3518,22 @@ int
 FunctionCallExpr::EstimateCost() const {
     if (isLaunch)
         return COST_TASK_LAUNCH;
-    else if (dynamic_cast<FunctionSymbolExpr *>(func) == NULL) {
-        // it's going through a function pointer
-        const Type *fpType = func->GetType();
-        if (fpType != NULL) {
-            Assert(dynamic_cast<const PointerType *>(fpType) != NULL);
-            if (fpType->IsUniformType())
-                return COST_FUNPTR_UNIFORM;
+
+    const Type *type = func->GetType();
+    if (type == NULL)
+        return 0;
+
+    const PointerType *pt = dynamic_cast<const PointerType *>(type);
+    if (pt != NULL)
+        type = type->GetBaseType();
+    const FunctionType *ftype = dynamic_cast<const FunctionType *>(type);
+
+    if (ftype->costOverride > -1)
+        return ftype->costOverride;
+
+    if (pt != NULL)
+        return pt->IsUniformType() ? COST_FUNPTR_UNIFORM : COST_FUNPTR_VARYING;
     else
-                return COST_FUNPTR_VARYING;
-        }
-    }
         return COST_FUNCALL;
 }
 

type.cpp

@@ -2329,6 +2329,8 @@ FunctionType::FunctionType(const Type *r, const std::vector<const Type *> &a,
       paramDefaults(std::vector<ConstExpr *>(a.size(), NULL)),
       paramPositions(std::vector<SourcePos>(a.size(), p)) {
     Assert(returnType != NULL);
+    isSafe = false;
+    costOverride = -1;
 }
 
 
@@ -2343,6 +2345,8 @@ FunctionType::FunctionType(const Type *r, const std::vector<const Type *> &a,
            paramNames.size() == paramDefaults.size() &&
            paramDefaults.size() == paramPositions.size());
     Assert(returnType != NULL);
+    isSafe = false;
+    costOverride = -1;
 }
 
 
@@ -2434,8 +2438,13 @@ FunctionType::ResolveUnboundVariability(Variability v) const {
         pt.push_back(paramTypes[i]->ResolveUnboundVariability(v));
     }
 
-    return new FunctionType(rt, pt, paramNames, paramDefaults,
-                            paramPositions, isTask, isExported, isExternC);
+    FunctionType *ret = new FunctionType(rt, pt, paramNames, paramDefaults,
+                                         paramPositions, isTask, isExported,
+                                         isExternC);
+    ret->isSafe = isSafe;
+    ret->costOverride = costOverride;
+
+    return ret;
 }
 
 
@@ -2457,6 +2466,12 @@ std::string
 FunctionType::GetString() const {
     std::string ret;
     if (isTask) ret += "task ";
+    if (isSafe) ret += "/*safe*/ ";
+    if (costOverride > 0) {
+        char buf[32];
+        sprintf(buf, "/*cost=%d*/ ", costOverride);
+        ret += buf;
+    }
     if (returnType != NULL)
         ret += returnType->GetString();
     else

type.h

@@ -801,6 +801,14 @@ public:
         function in the source program. */
     const bool isExternC;
 
+    /** Indicates whether this function has been declared to be safe to run
+        with an all-off mask. */
+    bool isSafe;
+
+    /** If non-negative, this provides a user-supplied override to the cost
+        function estimate for the function. */ 
+    int costOverride;
+
 private:
     const Type * const returnType;