1 //===-- PreCGRewrite.cpp --------------------------------------------------===//
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 // Coding style: https://mlir.llvm.org/getting_started/DeveloperGuide/
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "CGOps.h"
14 #include "PassDetail.h"
15 #include "flang/Optimizer/CodeGen/CodeGen.h"
16 #include "flang/Optimizer/Dialect/FIRDialect.h"
17 #include "flang/Optimizer/Dialect/FIROps.h"
18 #include "flang/Optimizer/Dialect/FIRType.h"
19 #include "flang/Optimizer/Support/FIRContext.h"
20 #include "mlir/Transforms/DialectConversion.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/Support/Debug.h"
23 
24 //===----------------------------------------------------------------------===//
25 // Codegen rewrite: rewriting of subgraphs of ops
26 //===----------------------------------------------------------------------===//
27 
28 using namespace fir;
29 
30 #define DEBUG_TYPE "flang-codegen-rewrite"
31 
32 static void populateShape(llvm::SmallVectorImpl<mlir::Value> &vec,
33                           ShapeOp shape) {
34   vec.append(shape.extents().begin(), shape.extents().end());
35 }
36 
37 // Operands of fir.shape_shift split into two vectors.
38 static void populateShapeAndShift(llvm::SmallVectorImpl<mlir::Value> &shapeVec,
39                                   llvm::SmallVectorImpl<mlir::Value> &shiftVec,
40                                   ShapeShiftOp shift) {
41   auto endIter = shift.pairs().end();
42   for (auto i = shift.pairs().begin(); i != endIter;) {
43     shiftVec.push_back(*i++);
44     shapeVec.push_back(*i++);
45   }
46 }
47 
48 static void populateShift(llvm::SmallVectorImpl<mlir::Value> &vec,
49                           ShiftOp shift) {
50   vec.append(shift.origins().begin(), shift.origins().end());
51 }
52 
53 namespace {
54 
55 /// Convert fir.embox to the extended form where necessary.
56 ///
57 /// The embox operation can take arguments that specify multidimensional array
58 /// properties at runtime. These properties may be shared between distinct
59 /// objects that have the same properties. Before we lower these small DAGs to
60 /// LLVM-IR, we gather all the information into a single extended operation. For
61 /// example,
62 /// ```
63 /// %1 = fir.shape_shift %4, %5 : (index, index) -> !fir.shapeshift<1>
64 /// %2 = fir.slice %6, %7, %8 : (index, index, index) -> !fir.slice<1>
65 /// %3 = fir.embox %0 (%1) [%2] : (!fir.ref<!fir.array<?xi32>>, !fir.shapeshift<1>, !fir.slice<1>) -> !fir.box<!fir.array<?xi32>>
66 /// ```
67 /// can be rewritten as
68 /// ```
69 /// %1 = fircg.ext_embox %0(%5) origin %4[%6, %7, %8] : (!fir.ref<!fir.array<?xi32>>, index, index, index, index, index) -> !fir.box<!fir.array<?xi32>>
70 /// ```
71 class EmboxConversion : public mlir::OpRewritePattern<EmboxOp> {
72 public:
73   using OpRewritePattern::OpRewritePattern;
74 
75   mlir::LogicalResult
76   matchAndRewrite(EmboxOp embox,
77                   mlir::PatternRewriter &rewriter) const override {
78     auto shapeVal = embox.getShape();
79     // If the embox does not include a shape, then do not convert it
80     if (shapeVal)
81       return rewriteDynamicShape(embox, rewriter, shapeVal);
82     if (auto boxTy = embox.getType().dyn_cast<BoxType>())
83       if (auto seqTy = boxTy.getEleTy().dyn_cast<SequenceType>())
84         if (seqTy.hasConstantShape())
85           return rewriteStaticShape(embox, rewriter, seqTy);
86     return mlir::failure();
87   }
88 
89   mlir::LogicalResult rewriteStaticShape(EmboxOp embox,
90                                          mlir::PatternRewriter &rewriter,
91                                          SequenceType seqTy) const {
92     auto loc = embox.getLoc();
93     llvm::SmallVector<mlir::Value> shapeOpers;
94     auto idxTy = rewriter.getIndexType();
95     for (auto ext : seqTy.getShape()) {
96       auto iAttr = rewriter.getIndexAttr(ext);
97       auto extVal = rewriter.create<mlir::ConstantOp>(loc, idxTy, iAttr);
98       shapeOpers.push_back(extVal);
99     }
100     auto xbox = rewriter.create<cg::XEmboxOp>(
101         loc, embox.getType(), embox.memref(), shapeOpers, llvm::None,
102         llvm::None, llvm::None, embox.lenParams());
103     LLVM_DEBUG(llvm::dbgs() << "rewriting " << embox << " to " << xbox << '\n');
104     rewriter.replaceOp(embox, xbox.getOperation()->getResults());
105     return mlir::success();
106   }
107 
108   mlir::LogicalResult rewriteDynamicShape(EmboxOp embox,
109                                           mlir::PatternRewriter &rewriter,
110                                           mlir::Value shapeVal) const {
111     auto loc = embox.getLoc();
112     auto shapeOp = dyn_cast<ShapeOp>(shapeVal.getDefiningOp());
113     llvm::SmallVector<mlir::Value> shapeOpers;
114     llvm::SmallVector<mlir::Value> shiftOpers;
115     if (shapeOp) {
116       populateShape(shapeOpers, shapeOp);
117     } else {
118       auto shiftOp = dyn_cast<ShapeShiftOp>(shapeVal.getDefiningOp());
119       assert(shiftOp && "shape is neither fir.shape nor fir.shape_shift");
120       populateShapeAndShift(shapeOpers, shiftOpers, shiftOp);
121     }
122     llvm::SmallVector<mlir::Value> sliceOpers;
123     llvm::SmallVector<mlir::Value> subcompOpers;
124     if (auto s = embox.getSlice())
125       if (auto sliceOp = dyn_cast_or_null<SliceOp>(s.getDefiningOp())) {
126         sliceOpers.append(sliceOp.triples().begin(), sliceOp.triples().end());
127         subcompOpers.append(sliceOp.fields().begin(), sliceOp.fields().end());
128       }
129     auto xbox = rewriter.create<cg::XEmboxOp>(
130         loc, embox.getType(), embox.memref(), shapeOpers, shiftOpers,
131         sliceOpers, subcompOpers, embox.lenParams());
132     LLVM_DEBUG(llvm::dbgs() << "rewriting " << embox << " to " << xbox << '\n');
133     rewriter.replaceOp(embox, xbox.getOperation()->getResults());
134     return mlir::success();
135   }
136 };
137 
138 /// Convert fir.rebox to the extended form where necessary.
139 ///
140 /// For example,
141 /// ```
142 /// %5 = fir.rebox %3(%1) : (!fir.box<!fir.array<?xi32>>, !fir.shapeshift<1>) -> !fir.box<!fir.array<?xi32>>
143 /// ```
144 /// converted to
145 /// ```
146 /// %5 = fircg.ext_rebox %3(%13) origin %12 : (!fir.box<!fir.array<?xi32>>, index, index) -> !fir.box<!fir.array<?xi32>>
147 /// ```
148 class ReboxConversion : public mlir::OpRewritePattern<ReboxOp> {
149 public:
150   using OpRewritePattern::OpRewritePattern;
151 
152   mlir::LogicalResult
153   matchAndRewrite(ReboxOp rebox,
154                   mlir::PatternRewriter &rewriter) const override {
155     auto loc = rebox.getLoc();
156     llvm::SmallVector<mlir::Value> shapeOpers;
157     llvm::SmallVector<mlir::Value> shiftOpers;
158     if (auto shapeVal = rebox.shape()) {
159       if (auto shapeOp = dyn_cast<ShapeOp>(shapeVal.getDefiningOp()))
160         populateShape(shapeOpers, shapeOp);
161       else if (auto shiftOp = dyn_cast<ShapeShiftOp>(shapeVal.getDefiningOp()))
162         populateShapeAndShift(shapeOpers, shiftOpers, shiftOp);
163       else if (auto shiftOp = dyn_cast<ShiftOp>(shapeVal.getDefiningOp()))
164         populateShift(shiftOpers, shiftOp);
165       else
166         return mlir::failure();
167     }
168     llvm::SmallVector<mlir::Value> sliceOpers;
169     llvm::SmallVector<mlir::Value> subcompOpers;
170     if (auto s = rebox.slice())
171       if (auto sliceOp = dyn_cast_or_null<SliceOp>(s.getDefiningOp())) {
172         sliceOpers.append(sliceOp.triples().begin(), sliceOp.triples().end());
173         subcompOpers.append(sliceOp.fields().begin(), sliceOp.fields().end());
174       }
175 
176     auto xRebox = rewriter.create<cg::XReboxOp>(
177         loc, rebox.getType(), rebox.box(), shapeOpers, shiftOpers, sliceOpers,
178         subcompOpers);
179     LLVM_DEBUG(llvm::dbgs()
180                << "rewriting " << rebox << " to " << xRebox << '\n');
181     rewriter.replaceOp(rebox, xRebox.getOperation()->getResults());
182     return mlir::success();
183   }
184 };
185 
186 /// Convert all fir.array_coor to the extended form.
187 ///
188 /// For example,
189 /// ```
190 ///  %4 = fir.array_coor %addr (%1) [%2] %0 : (!fir.ref<!fir.array<?xi32>>, !fir.shapeshift<1>, !fir.slice<1>, index) -> !fir.ref<i32>
191 /// ```
192 /// converted to
193 /// ```
194 /// %40 = fircg.ext_array_coor %addr(%9) origin %8[%4, %5, %6<%39> : (!fir.ref<!fir.array<?xi32>>, index, index, index, index, index, index) -> !fir.ref<i32>
195 /// ```
196 class ArrayCoorConversion : public mlir::OpRewritePattern<ArrayCoorOp> {
197 public:
198   using OpRewritePattern::OpRewritePattern;
199 
200   mlir::LogicalResult
201   matchAndRewrite(ArrayCoorOp arrCoor,
202                   mlir::PatternRewriter &rewriter) const override {
203     auto loc = arrCoor.getLoc();
204     llvm::SmallVector<mlir::Value> shapeOpers;
205     llvm::SmallVector<mlir::Value> shiftOpers;
206     if (auto shapeVal = arrCoor.shape()) {
207       if (auto shapeOp = dyn_cast<ShapeOp>(shapeVal.getDefiningOp()))
208         populateShape(shapeOpers, shapeOp);
209       else if (auto shiftOp = dyn_cast<ShapeShiftOp>(shapeVal.getDefiningOp()))
210         populateShapeAndShift(shapeOpers, shiftOpers, shiftOp);
211       else if (auto shiftOp = dyn_cast<ShiftOp>(shapeVal.getDefiningOp()))
212         populateShift(shiftOpers, shiftOp);
213       else
214         return mlir::failure();
215     }
216     llvm::SmallVector<mlir::Value> sliceOpers;
217     llvm::SmallVector<mlir::Value> subcompOpers;
218     if (auto s = arrCoor.slice())
219       if (auto sliceOp = dyn_cast_or_null<SliceOp>(s.getDefiningOp())) {
220         sliceOpers.append(sliceOp.triples().begin(), sliceOp.triples().end());
221         subcompOpers.append(sliceOp.fields().begin(), sliceOp.fields().end());
222       }
223     auto xArrCoor = rewriter.create<cg::XArrayCoorOp>(
224         loc, arrCoor.getType(), arrCoor.memref(), shapeOpers, shiftOpers,
225         sliceOpers, subcompOpers, arrCoor.indices(), arrCoor.lenParams());
226     LLVM_DEBUG(llvm::dbgs()
227                << "rewriting " << arrCoor << " to " << xArrCoor << '\n');
228     rewriter.replaceOp(arrCoor, xArrCoor.getOperation()->getResults());
229     return mlir::success();
230   }
231 };
232 
233 class CodeGenRewrite : public CodeGenRewriteBase<CodeGenRewrite> {
234 public:
235   void runOnOperation() override final {
236     auto op = getOperation();
237     auto &context = getContext();
238     mlir::OpBuilder rewriter(&context);
239     mlir::ConversionTarget target(context);
240     target.addLegalDialect<FIROpsDialect, FIRCodeGenDialect,
241                            mlir::StandardOpsDialect>();
242     target.addIllegalOp<ArrayCoorOp>();
243     target.addIllegalOp<ReboxOp>();
244     target.addDynamicallyLegalOp<EmboxOp>([](EmboxOp embox) {
245       return !(embox.getShape() ||
246                embox.getType().cast<BoxType>().getEleTy().isa<SequenceType>());
247     });
248     mlir::OwningRewritePatternList patterns(&context);
249     patterns.insert<EmboxConversion, ArrayCoorConversion, ReboxConversion>(
250         &context);
251     if (mlir::failed(
252             mlir::applyPartialConversion(op, target, std::move(patterns)))) {
253       mlir::emitError(mlir::UnknownLoc::get(&context),
254                       "error in running the pre-codegen conversions");
255       signalPassFailure();
256     }
257   }
258 };
259 
260 } // namespace
261 
262 std::unique_ptr<mlir::Pass> fir::createFirCodeGenRewritePass() {
263   return std::make_unique<CodeGenRewrite>();
264 }
265