Enhance the customizable "Op" implementations in a bunch of ways:
 - Op classes can now provide customized matchers, allowing specializations
   beyond just a name match.
 - We now provide default implementations of verify/print hooks, so Op classes
   only need to implement them if they're doing custom stuff, and only have to
   implement the ones they're interested in.
 - "Base" now takes a variadic list of template template arguments, allowing
   concrete Op types to avoid passing the Concrete type multiple times.
 - Add new ZeroOperands trait.
 - Add verification hooks to Zero/One/Two operands and OneResult to check that
   ops using them are correctly formed.
 - Implement getOperand hooks to zero/one/two operand traits, and
   getResult/getType hook to OneResult trait.
 - Add a new "constant" op to show some of this off, with a specialization for
   the constant case.

This patch also splits op validity checks out to a new test/IR/invalid-ops.mlir
file.

This stubs out support for default asmprinter support.  My next planned patch
building on top of this will make asmprinter hooks real and will revise this.

PiperOrigin-RevId: 205833214
diff --git a/lib/IR/StandardOps.cpp b/lib/IR/StandardOps.cpp
index d1ddf65..ce9857a 100644
--- a/lib/IR/StandardOps.cpp
+++ b/lib/IR/StandardOps.cpp
@@ -17,6 +17,8 @@
 
 #include "mlir/IR/StandardOps.h"
 #include "mlir/IR/OperationSet.h"
+#include "mlir/IR/SSAValue.h"
+#include "mlir/IR/Types.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace mlir;
 
@@ -32,24 +34,62 @@
   return nullptr;
 }
 
+/// The constant op requires an attribute, and furthermore requires that it
+/// matches the return type.
+const char *ConstantOp::verify() const {
+  auto *value = getValue();
+  if (!value)
+    return "requires a 'value' attribute";
+
+  auto *type = this->getType();
+  if (isa<IntegerType>(type)) {
+    if (!isa<IntegerAttr>(value))
+      return "requires 'value' to be an integer for an integer result type";
+    return nullptr;
+  }
+
+  if (isa<FunctionType>(type)) {
+    // TODO: Verify a function attr.
+  }
+
+  return "requires a result type that aligns with the 'value' attribute";
+}
+
+/// ConstantIntOp only matches values whose result type is an IntegerType.
+bool ConstantIntOp::isClassFor(const Operation *op) {
+  return ConstantOp::isClassFor(op) &&
+         isa<IntegerType>(op->getResult(0)->getType());
+}
+
 void DimOp::print(raw_ostream &os) const {
   os << "dim xxx, " << getIndex() << " : sometype";
 }
 
 const char *DimOp::verify() const {
-  // TODO: Check that the operand has tensor or memref type.
-
   // Check that we have an integer index operand.
   auto indexAttr = getAttrOfType<IntegerAttr>("index");
   if (!indexAttr)
-    return "'dim' op requires an integer attribute named 'index'";
+    return "requires an integer attribute named 'index'";
+  uint64_t index = (uint64_t)indexAttr->getValue();
 
-  // TODO: Check that the index is in range.
+  auto *type = getOperand()->getType();
+  if (auto *tensorType = dyn_cast<RankedTensorType>(type)) {
+    if (index >= tensorType->getRank())
+      return "index is out of range";
+  } else if (auto *memrefType = dyn_cast<MemRefType>(type)) {
+    if (index >= memrefType->getRank())
+      return "index is out of range";
+
+  } else if (isa<UnrankedTensorType>(type)) {
+    // ok, assumed to be in-range.
+  } else {
+    return "requires an operand with tensor or memref type";
+  }
 
   return nullptr;
 }
 
 /// Install the standard operations in the specified operation set.
 void mlir::registerStandardOperations(OperationSet &opSet) {
-  opSet.addOperations<AddFOp, DimOp>(/*prefix=*/ "");
+  opSet.addOperations<AddFOp, ConstantOp, DimOp>(/*prefix=*/"");
 }