[SIL] Support SILFunction as a GraphOperationInst attribute. (#17374)

- Implement parsing/printing for SILFunction SymbolicValues.
  - It's necessary to include function type in the textual representation to
    enable forward references to SIL functions.
  - Assert that SILFunction SymbolicValue has no conformances before printing.
- Update test.

Author: dan-zheng

lib/ParseSIL/ParseSIL.cpp

@@ -895,6 +895,7 @@ void SILParser::convertRequirements(SILFunction *F,
 /// - A metatype (the instance type is parsed) ($Float).
 /// - An aggregate ([i32 1, i64 2, f32 3.0]).
 ///   - Aggregates values represent constant arrays/structs/tuples.
+/// - A SIL function reference (@foo : $(Int) -> Int).
 /// Returns true on error.
 static bool parseSymbolicValue(SymbolicValue &value, SILParser &SP,
                                SILBuilder &B) {
@@ -1010,6 +1011,15 @@ static bool parseSymbolicValue(SymbolicValue &value, SILParser &SP,
     value = SymbolicValue::getMetatype(metatype);
     return false;
   }
+  // Handle SIL function references.
+  if (P.Tok.is(tok::at_sign)) {
+    SILFunction *func;
+    SILLocation funcLoc = RegularLocation(P.getEndOfPreviousLoc());
+    if (SP.parseSILFunctionRef(funcLoc, func))
+      return true;
+    value = SymbolicValue::getFunction(func);
+    return false;
+  }
   // Handle aggregate literals.
   if (P.Tok.is(tok::l_square)) {
     SourceLoc lSquareLoc = P.consumeToken(tok::l_square);

lib/SIL/SILPrinter.cpp

@@ -1217,6 +1217,15 @@ class SILPrinter : public SILInstructionVisitor<SILPrinter> {
       *this << SILType::getPrimitiveObjectType(metatype.getInstanceType());
       return;
     }
+    case SymbolicValue::Function: {
+      assert(!v.getFunctionValue().second &&
+             "SILFunction SymbolicValues with protocol conformances cannot be "
+             "printed");
+      auto function = v.getFunctionValue().first;
+      *this << "@" << function->getName();
+      *this << " : $" << function->getLoweredFunctionType();
+      return;
+    }
     case SymbolicValue::Aggregate:
       *this << "[";
       interleave(v.getAggregateValue(), [&](SymbolicValue element) {
@@ -1226,7 +1235,6 @@ class SILPrinter : public SILInstructionVisitor<SILPrinter> {
       });
       *this << "]";
       return;
-    case SymbolicValue::Function:
     case SymbolicValue::UninitMemory:
     case SymbolicValue::Unknown:
       llvm_unreachable("Unimplemented SymbolicValue case");

test/TensorFlow/graph_op_inst.sil

@@ -15,7 +15,8 @@ bb0:
   %2 = graph_op "tf.Dummy"() {float1: f64 3.14, float2: f32 -3.14} : $Tensor<Float>
   %3 = graph_op "tf.Dummy"() {string1: "hello", string2: "world"} : $Tensor<Float>
   %4 = graph_op "tf.Dummy"() {metatype1: $Float, metatype2: $Tensor<Float>} : $Tensor<Float>
-  %5 = graph_op "tf.Dummy"() {array: [[i8 1, i32 -2], [f32 -1.0, $Float]]} : $Tensor<Float>
+  %5 = graph_op "tf.Dummy"() {function1: @chained_op_test : $@convention(thin) (Tensor<Float>, Tensor<Float>) -> Tensor<Float>} : $Tensor<Float>
+  %6 = graph_op "tf.Dummy"() {array: [[i8 1, i32 -2], [f32 -1.0, $Float]]} : $Tensor<Float>
   return %0 : $Tensor<Float>
 }
 
@@ -26,7 +27,8 @@ bb0:
 // CHECK-NEXT:   %2 = graph_op "tf.Dummy"() {float1: f64 0x40091EB851EB851F /* 3.1400000000000001 */, float2: f32 0xC048F5C3 /* -3.1400001 */} : $Tensor<Float>
 // CHECK-NEXT:   %3 = graph_op "tf.Dummy"() {string1: "hello", string2: "world"} : $Tensor<Float>
 // CHECK-NEXT:   %4 = graph_op "tf.Dummy"() {metatype1: $Float, metatype2: $Tensor<Float>} : $Tensor<Float>
-// CHECK-NEXT:   %5 = graph_op "tf.Dummy"() {array: {{\[\[}}i8 1, i32 -2], [f32 0xBF800000 /* -1 */, $Float]]} : $Tensor<Float>
+// CHECK-NEXT:   %5 = graph_op "tf.Dummy"() {function1: @chained_op_test : $@convention(thin) (Tensor<Float>, Tensor<Float>) -> Tensor<Float>} : $Tensor<Float>
+// CHECK-NEXT:   %6 = graph_op "tf.Dummy"() {array: {{\[\[}}i8 1, i32 -2], [f32 0xBF800000 /* -1 */, $Float]]} : $Tensor<Float>
 // CHECK-NEXT:   return %0 : $Tensor<Float>
 // CHECK-NEXT: }