Reconcile EmitC changes with upstream (#221)

Author: cferry-AMD

mlir/docs/Dialects/emitc.md

@@ -10,11 +10,18 @@ The following convention is followed:
     `emitc.call_opaque` operation, C++11 is required.
 *   If floating-point type template arguments are passed to an `emitc.call_opaque`
     operation, C++20 is required.
+*   If `ssize_t` is used, then the code requires the POSIX header `sys/types.h`
+    or any of the C++ headers in which the type is defined.
 *   Else the generated code is compatible with C99.
 
 These restrictions are neither inherent to the EmitC dialect itself nor to the
 Cpp emitter and therefore need to be considered while implementing conversions.
 
+Type conversions are provided for the MLIR type `index` into the unsigned `size_t`
+type and its signed counterpart `ptrdiff_t`. Conversions between these two types
+are only valid if the `index`-typed values are within 
+`[PTRDIFF_MIN, PTRDIFF_MAX]`.
+
 After the conversion, C/C++ code can be emitted with `mlir-translate`. The tool
 supports translating MLIR to C/C++ by passing `-mlir-to-cpp`. Furthermore, code
 with variables declared at top can be generated by passing the additional

mlir/include/mlir/Conversion/ArithToEmitC/ArithToEmitC.h

@@ -13,8 +13,8 @@ namespace mlir {
 class RewritePatternSet;
 class TypeConverter;
 
-void populateArithToEmitCPatterns(RewritePatternSet &patterns,
-                                  TypeConverter &typeConverter);
+void populateArithToEmitCPatterns(TypeConverter &typeConverter,
+                                  RewritePatternSet &patterns);
 } // namespace mlir
 
 #endif // MLIR_CONVERSION_ARITHTOEMITC_ARITHTOEMITC_H

mlir/include/mlir/Dialect/EmitC/IR/EmitC.h

@@ -45,7 +45,7 @@ bool isIntegerIndexOrOpaqueType(Type type);
 bool isSupportedFloatType(mlir::Type type);
 
 /// Determines whether \p type is a emitc.size_t/ssize_t type.
-bool isAnySizeTType(mlir::Type type);
+bool isPointerWideType(mlir::Type type);
 
 } // namespace emitc
 } // namespace mlir

mlir/include/mlir/Dialect/EmitC/IR/EmitC.td

@@ -51,8 +51,8 @@ class EmitC_BinaryOp<string mnemonic, list<Trait> traits = []> :
 def CExpression : NativeOpTrait<"emitc::CExpression">;
 
 // Types only used in binary arithmetic operations.
-def IntegerIndexOrOpaqueType : AnyTypeOf<[EmitCIntegerType, Index,
-  EmitC_SignedSizeT, EmitC_SizeT, EmitC_OpaqueType]>;
+def IntegerIndexOrOpaqueType : Type<CPred<"emitc::isIntegerIndexOrOpaqueType($_self)">,
+"integer, index or opaque type supported by EmitC">;
 def FloatIntegerIndexOrOpaqueType : AnyTypeOf<[EmitCFloatType, IntegerIndexOrOpaqueType]>;
 
 def EmitC_AddOp : EmitC_BinaryOp<"add", [CExpression]> {
@@ -288,7 +288,6 @@ def EmitC_CastOp : EmitC_Op<"cast",
   let arguments = (ins EmitCType:$source);
   let results = (outs EmitCType:$dest);
   let assemblyFormat = "$source attr-dict `:` type($source) `to` type($dest)";
-  let hasFolder = 1;
 }
 
 def EmitC_CmpOp : EmitC_BinaryOp<"cmp", [CExpression]> {

mlir/include/mlir/Dialect/EmitC/IR/EmitCTypes.td

@@ -75,9 +75,9 @@ def EmitC_ArrayType : EmitC_Type<"Array", "array", [ShapedTypeInterface]> {
                         Type elementType) const;
 
     static bool isValidElementType(Type type) {
-      return type.isIntOrIndexOrFloat() ||
-         emitc::isAnySizeTType(type) ||
-         llvm::isa<PointerType, OpaqueType>(type);
+      return emitc::isSupportedFloatType(type) ||
+         emitc::isIntegerIndexOrOpaqueType(type) ||
+         llvm::isa<PointerType>(type);
     }
   }];
   let genVerifyDecl = 1;
@@ -133,10 +133,29 @@ def EmitC_PointerType : EmitC_Type<"Pointer", "ptr"> {
 
 def EmitC_SignedSizeT : EmitC_Type<"SignedSizeT", "ssize_t"> {
   let summary = "EmitC signed size type";
+  let description = [{
+    Data type representing all values of `emitc.size_t`, plus -1.
+    It corresponds to `ssize_t` found in `<sys/types.h>`.
+    
+    Use of this type causes the code to be non-C99 compliant.
+  }];
+}
+
+def EmitC_PtrDiffT : EmitC_Type<"PtrDiffT", "ptrdiff_t"> {
+  let summary = "EmitC signed pointer diff type";
+  let description = [{
+    Signed data type as wide as platform-specific pointer types.
+    In particular, it is as wide as `emitc.size_t`.
+    It corresponds to `ptrdiff_t` found in `<stddef.h>`.
+  }];
 }
 
 def EmitC_SizeT : EmitC_Type<"SizeT", "size_t"> {
   let summary = "EmitC unsigned size type";
+  let description = [{
+    Unsigned data type as wide as platform-specific pointer types.
+    It corresponds to `size_t` found in `<stddef.h>`.
+  }];
 }
 
 #endif // MLIR_DIALECT_EMITC_IR_EMITCTYPES

mlir/include/mlir/Dialect/EmitC/Transforms/TypeConversions.h

@@ -11,7 +11,8 @@
 
 namespace mlir {
 class TypeConverter;
-void populateEmitCSizeTypeConversions(TypeConverter &converter);
+void populateEmitCSizeTTypeConversions(TypeConverter &converter);
+
 } // namespace mlir
 
 #endif // MLIR_DIALECT_EMITC_TRANSFORMS_TYPECONVERSIONS_H