1 //===- FunctionImplementation.cpp - Utilities for function-like ops -------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "mlir/IR/FunctionImplementation.h"
10 #include "mlir/IR/Builders.h"
11 #include "mlir/IR/FunctionInterfaces.h"
12 #include "mlir/IR/SymbolTable.h"
13 
14 using namespace mlir;
15 
16 ParseResult mlir::function_interface_impl::parseFunctionArgumentList(
17     OpAsmParser &parser, bool allowAttributes, bool allowVariadic,
18     SmallVectorImpl<OpAsmParser::UnresolvedOperand> &argNames,
19     SmallVectorImpl<Type> &argTypes, SmallVectorImpl<NamedAttrList> &argAttrs,
20     bool &isVariadic) {
21   if (parser.parseLParen())
22     return failure();
23 
24   // The argument list either has to consistently have ssa-id's followed by
25   // types, or just be a type list.  It isn't ok to sometimes have SSA ID's and
26   // sometimes not.
27   auto parseArgument = [&]() -> ParseResult {
28     SMLoc loc = parser.getCurrentLocation();
29 
30     // Parse argument name if present.
31     OpAsmParser::UnresolvedOperand argument;
32     Type argumentType;
33     auto hadSSAValue = parser.parseOptionalOperand(argument,
34                                                    /*allowResultNumber=*/false);
35     if (hadSSAValue.hasValue()) {
36       if (failed(hadSSAValue.getValue()))
37         return failure(); // Argument was present but malformed.
38 
39       // Reject this if the preceding argument was missing a name.
40       if (argNames.empty() && !argTypes.empty())
41         return parser.emitError(loc, "expected type instead of SSA identifier");
42 
43       // Parse required type.
44       if (parser.parseColonType(argumentType))
45         return failure();
46     } else if (allowVariadic && succeeded(parser.parseOptionalEllipsis())) {
47       isVariadic = true;
48       return success();
49     } else if (!argNames.empty()) {
50       // Reject this if the preceding argument had a name.
51       return parser.emitError(loc, "expected SSA identifier");
52     } else if (parser.parseType(argumentType)) {
53       return failure();
54     }
55 
56     // Add the argument type.
57     argTypes.push_back(argumentType);
58 
59     // Parse any argument attributes and source location information.
60     NamedAttrList attrs;
61     if (parser.parseOptionalAttrDict(attrs) ||
62         parser.parseOptionalLocationSpecifier(argument.sourceLoc))
63       return failure();
64 
65     if (!allowAttributes && !attrs.empty())
66       return parser.emitError(loc, "expected arguments without attributes");
67     argAttrs.push_back(attrs);
68 
69     // If we had an argument name, then remember the parsed argument.
70     if (!argument.name.empty())
71       argNames.push_back(argument);
72     return success();
73   };
74 
75   // Parse the function arguments.
76   isVariadic = false;
77   if (failed(parser.parseOptionalRParen())) {
78     do {
79       unsigned numTypedArguments = argTypes.size();
80       if (parseArgument())
81         return failure();
82 
83       SMLoc loc = parser.getCurrentLocation();
84       if (argTypes.size() == numTypedArguments &&
85           succeeded(parser.parseOptionalComma()))
86         return parser.emitError(
87             loc, "variadic arguments must be in the end of the argument list");
88     } while (succeeded(parser.parseOptionalComma()));
89     parser.parseRParen();
90   }
91 
92   return success();
93 }
94 
95 /// Parse a function result list.
96 ///
97 ///   function-result-list ::= function-result-list-parens
98 ///                          | non-function-type
99 ///   function-result-list-parens ::= `(` `)`
100 ///                                 | `(` function-result-list-no-parens `)`
101 ///   function-result-list-no-parens ::= function-result (`,` function-result)*
102 ///   function-result ::= type attribute-dict?
103 ///
104 static ParseResult
105 parseFunctionResultList(OpAsmParser &parser, SmallVectorImpl<Type> &resultTypes,
106                         SmallVectorImpl<NamedAttrList> &resultAttrs) {
107   if (failed(parser.parseOptionalLParen())) {
108     // We already know that there is no `(`, so parse a type.
109     // Because there is no `(`, it cannot be a function type.
110     Type ty;
111     if (parser.parseType(ty))
112       return failure();
113     resultTypes.push_back(ty);
114     resultAttrs.emplace_back();
115     return success();
116   }
117 
118   // Special case for an empty set of parens.
119   if (succeeded(parser.parseOptionalRParen()))
120     return success();
121 
122   // Parse individual function results.
123   do {
124     resultTypes.emplace_back();
125     resultAttrs.emplace_back();
126     if (parser.parseType(resultTypes.back()) ||
127         parser.parseOptionalAttrDict(resultAttrs.back())) {
128       return failure();
129     }
130   } while (succeeded(parser.parseOptionalComma()));
131   return parser.parseRParen();
132 }
133 
134 ParseResult mlir::function_interface_impl::parseFunctionSignature(
135     OpAsmParser &parser, bool allowVariadic,
136     SmallVectorImpl<OpAsmParser::UnresolvedOperand> &argNames,
137     SmallVectorImpl<Type> &argTypes, SmallVectorImpl<NamedAttrList> &argAttrs,
138     bool &isVariadic, SmallVectorImpl<Type> &resultTypes,
139     SmallVectorImpl<NamedAttrList> &resultAttrs) {
140   bool allowArgAttrs = true;
141   if (parseFunctionArgumentList(parser, allowArgAttrs, allowVariadic, argNames,
142                                 argTypes, argAttrs, isVariadic))
143     return failure();
144   if (succeeded(parser.parseOptionalArrow()))
145     return parseFunctionResultList(parser, resultTypes, resultAttrs);
146   return success();
147 }
148 
149 /// Implementation of `addArgAndResultAttrs` that is attribute list type
150 /// agnostic.
151 template <typename AttrListT, typename AttrArrayBuildFnT>
152 static void addArgAndResultAttrsImpl(Builder &builder, OperationState &result,
153                                      ArrayRef<AttrListT> argAttrs,
154                                      ArrayRef<AttrListT> resultAttrs,
155                                      AttrArrayBuildFnT &&buildAttrArrayFn) {
156   auto nonEmptyAttrsFn = [](const AttrListT &attrs) { return !attrs.empty(); };
157 
158   // Add the attributes to the function arguments.
159   if (!argAttrs.empty() && llvm::any_of(argAttrs, nonEmptyAttrsFn)) {
160     ArrayAttr attrDicts = builder.getArrayAttr(buildAttrArrayFn(argAttrs));
161     result.addAttribute(function_interface_impl::getArgDictAttrName(),
162                         attrDicts);
163   }
164   // Add the attributes to the function results.
165   if (!resultAttrs.empty() && llvm::any_of(resultAttrs, nonEmptyAttrsFn)) {
166     ArrayAttr attrDicts = builder.getArrayAttr(buildAttrArrayFn(resultAttrs));
167     result.addAttribute(function_interface_impl::getResultDictAttrName(),
168                         attrDicts);
169   }
170 }
171 
172 void mlir::function_interface_impl::addArgAndResultAttrs(
173     Builder &builder, OperationState &result, ArrayRef<DictionaryAttr> argAttrs,
174     ArrayRef<DictionaryAttr> resultAttrs) {
175   auto buildFn = [](ArrayRef<DictionaryAttr> attrs) {
176     return ArrayRef<Attribute>(attrs.data(), attrs.size());
177   };
178   addArgAndResultAttrsImpl(builder, result, argAttrs, resultAttrs, buildFn);
179 }
180 void mlir::function_interface_impl::addArgAndResultAttrs(
181     Builder &builder, OperationState &result, ArrayRef<NamedAttrList> argAttrs,
182     ArrayRef<NamedAttrList> resultAttrs) {
183   MLIRContext *context = builder.getContext();
184   auto buildFn = [=](ArrayRef<NamedAttrList> attrs) {
185     return llvm::to_vector<8>(
186         llvm::map_range(attrs, [=](const NamedAttrList &attrList) -> Attribute {
187           return attrList.getDictionary(context);
188         }));
189   };
190   addArgAndResultAttrsImpl(builder, result, argAttrs, resultAttrs, buildFn);
191 }
192 
193 ParseResult mlir::function_interface_impl::parseFunctionOp(
194     OpAsmParser &parser, OperationState &result, bool allowVariadic,
195     FuncTypeBuilder funcTypeBuilder) {
196   SmallVector<OpAsmParser::UnresolvedOperand> entryArgs;
197   SmallVector<NamedAttrList> argAttrs;
198   SmallVector<NamedAttrList> resultAttrs;
199   SmallVector<Type> argTypes;
200   SmallVector<Type> resultTypes;
201   auto &builder = parser.getBuilder();
202 
203   // Parse visibility.
204   impl::parseOptionalVisibilityKeyword(parser, result.attributes);
205 
206   // Parse the name as a symbol.
207   StringAttr nameAttr;
208   if (parser.parseSymbolName(nameAttr, SymbolTable::getSymbolAttrName(),
209                              result.attributes))
210     return failure();
211 
212   // Parse the function signature.
213   SMLoc signatureLocation = parser.getCurrentLocation();
214   bool isVariadic = false;
215   if (parseFunctionSignature(parser, allowVariadic, entryArgs, argTypes,
216                              argAttrs, isVariadic, resultTypes, resultAttrs))
217     return failure();
218 
219   std::string errorMessage;
220   Type type = funcTypeBuilder(builder, argTypes, resultTypes,
221                               VariadicFlag(isVariadic), errorMessage);
222   if (!type) {
223     return parser.emitError(signatureLocation)
224            << "failed to construct function type"
225            << (errorMessage.empty() ? "" : ": ") << errorMessage;
226   }
227   result.addAttribute(getTypeAttrName(), TypeAttr::get(type));
228 
229   // If function attributes are present, parse them.
230   NamedAttrList parsedAttributes;
231   SMLoc attributeDictLocation = parser.getCurrentLocation();
232   if (parser.parseOptionalAttrDictWithKeyword(parsedAttributes))
233     return failure();
234 
235   // Disallow attributes that are inferred from elsewhere in the attribute
236   // dictionary.
237   for (StringRef disallowed :
238        {SymbolTable::getVisibilityAttrName(), SymbolTable::getSymbolAttrName(),
239         getTypeAttrName()}) {
240     if (parsedAttributes.get(disallowed))
241       return parser.emitError(attributeDictLocation, "'")
242              << disallowed
243              << "' is an inferred attribute and should not be specified in the "
244                 "explicit attribute dictionary";
245   }
246   result.attributes.append(parsedAttributes);
247 
248   // Add the attributes to the function arguments.
249   assert(argAttrs.size() == argTypes.size());
250   assert(resultAttrs.size() == resultTypes.size());
251   addArgAndResultAttrs(builder, result, argAttrs, resultAttrs);
252 
253   // Parse the optional function body. The printer will not print the body if
254   // its empty, so disallow parsing of empty body in the parser.
255   auto *body = result.addRegion();
256   SMLoc loc = parser.getCurrentLocation();
257   OptionalParseResult parseResult = parser.parseOptionalRegion(
258       *body, entryArgs, entryArgs.empty() ? ArrayRef<Type>() : argTypes,
259       /*enableNameShadowing=*/false);
260   if (parseResult.hasValue()) {
261     if (failed(*parseResult))
262       return failure();
263     // Function body was parsed, make sure its not empty.
264     if (body->empty())
265       return parser.emitError(loc, "expected non-empty function body");
266   }
267   return success();
268 }
269 
270 /// Print a function result list. The provided `attrs` must either be null, or
271 /// contain a set of DictionaryAttrs of the same arity as `types`.
272 static void printFunctionResultList(OpAsmPrinter &p, ArrayRef<Type> types,
273                                     ArrayAttr attrs) {
274   assert(!types.empty() && "Should not be called for empty result list.");
275   assert((!attrs || attrs.size() == types.size()) &&
276          "Invalid number of attributes.");
277 
278   auto &os = p.getStream();
279   bool needsParens = types.size() > 1 || types[0].isa<FunctionType>() ||
280                      (attrs && !attrs[0].cast<DictionaryAttr>().empty());
281   if (needsParens)
282     os << '(';
283   llvm::interleaveComma(llvm::seq<size_t>(0, types.size()), os, [&](size_t i) {
284     p.printType(types[i]);
285     if (attrs)
286       p.printOptionalAttrDict(attrs[i].cast<DictionaryAttr>().getValue());
287   });
288   if (needsParens)
289     os << ')';
290 }
291 
292 void mlir::function_interface_impl::printFunctionSignature(
293     OpAsmPrinter &p, Operation *op, ArrayRef<Type> argTypes, bool isVariadic,
294     ArrayRef<Type> resultTypes) {
295   Region &body = op->getRegion(0);
296   bool isExternal = body.empty();
297 
298   p << '(';
299   ArrayAttr argAttrs = op->getAttrOfType<ArrayAttr>(getArgDictAttrName());
300   for (unsigned i = 0, e = argTypes.size(); i < e; ++i) {
301     if (i > 0)
302       p << ", ";
303 
304     if (!isExternal) {
305       ArrayRef<NamedAttribute> attrs;
306       if (argAttrs)
307         attrs = argAttrs[i].cast<DictionaryAttr>().getValue();
308       p.printRegionArgument(body.getArgument(i), attrs);
309     } else {
310       p.printType(argTypes[i]);
311       if (argAttrs)
312         p.printOptionalAttrDict(argAttrs[i].cast<DictionaryAttr>().getValue());
313     }
314   }
315 
316   if (isVariadic) {
317     if (!argTypes.empty())
318       p << ", ";
319     p << "...";
320   }
321 
322   p << ')';
323 
324   if (!resultTypes.empty()) {
325     p.getStream() << " -> ";
326     auto resultAttrs = op->getAttrOfType<ArrayAttr>(getResultDictAttrName());
327     printFunctionResultList(p, resultTypes, resultAttrs);
328   }
329 }
330 
331 void mlir::function_interface_impl::printFunctionAttributes(
332     OpAsmPrinter &p, Operation *op, unsigned numInputs, unsigned numResults,
333     ArrayRef<StringRef> elided) {
334   // Print out function attributes, if present.
335   SmallVector<StringRef, 2> ignoredAttrs = {
336       ::mlir::SymbolTable::getSymbolAttrName(), getTypeAttrName(),
337       getArgDictAttrName(), getResultDictAttrName()};
338   ignoredAttrs.append(elided.begin(), elided.end());
339 
340   p.printOptionalAttrDictWithKeyword(op->getAttrs(), ignoredAttrs);
341 }
342 
343 void mlir::function_interface_impl::printFunctionOp(OpAsmPrinter &p,
344                                                     FunctionOpInterface op,
345                                                     bool isVariadic) {
346   // Print the operation and the function name.
347   auto funcName =
348       op->getAttrOfType<StringAttr>(SymbolTable::getSymbolAttrName())
349           .getValue();
350   p << ' ';
351 
352   StringRef visibilityAttrName = SymbolTable::getVisibilityAttrName();
353   if (auto visibility = op->getAttrOfType<StringAttr>(visibilityAttrName))
354     p << visibility.getValue() << ' ';
355   p.printSymbolName(funcName);
356 
357   ArrayRef<Type> argTypes = op.getArgumentTypes();
358   ArrayRef<Type> resultTypes = op.getResultTypes();
359   printFunctionSignature(p, op, argTypes, isVariadic, resultTypes);
360   printFunctionAttributes(p, op, argTypes.size(), resultTypes.size(),
361                           {visibilityAttrName});
362   // Print the body if this is not an external function.
363   Region &body = op->getRegion(0);
364   if (!body.empty()) {
365     p << ' ';
366     p.printRegion(body, /*printEntryBlockArgs=*/false,
367                   /*printBlockTerminators=*/true);
368   }
369 }
370