1//===- R600OpenCLImageTypeLoweringPass.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/// \file
10/// This pass resolves calls to OpenCL image attribute, image resource ID and
11/// sampler resource ID getter functions.
12///
13/// Image attributes (size and format) are expected to be passed to the kernel
14/// as kernel arguments immediately following the image argument itself,
15/// therefore this pass adds image size and format arguments to the kernel
16/// functions in the module. The kernel functions with image arguments are
17/// re-created using the new signature. The new arguments are added to the
18/// kernel metadata with kernel_arg_type set to "image_size" or "image_format".
19/// Note: this pass may invalidate pointers to functions.
20///
21/// Resource IDs of read-only images, write-only images and samplers are
22/// defined to be their index among the kernel arguments of the same
23/// type and access qualifier.
24//
25//===----------------------------------------------------------------------===//
26
27#include "R600.h"
28#include "llvm/ADT/SmallVector.h"
29#include "llvm/ADT/StringRef.h"
30#include "llvm/IR/Constants.h"
31#include "llvm/IR/Function.h"
32#include "llvm/IR/Instructions.h"
33#include "llvm/IR/Metadata.h"
34#include "llvm/IR/Module.h"
35#include "llvm/Pass.h"
36#include "llvm/Transforms/Utils/Cloning.h"
37
38using namespace llvm;
39
40static StringRef GetImageSizeFunc = "llvm.OpenCL.image.get.size";
41static StringRef GetImageFormatFunc = "llvm.OpenCL.image.get.format";
42static StringRef GetImageResourceIDFunc = "llvm.OpenCL.image.get.resource.id";
43static StringRef GetSamplerResourceIDFunc =
44 "llvm.OpenCL.sampler.get.resource.id";
45
46static StringRef ImageSizeArgMDType = "__llvm_image_size";
47static StringRef ImageFormatArgMDType = "__llvm_image_format";
48
49static StringRef KernelsMDNodeName = "opencl.kernels";
50static StringRef KernelArgMDNodeNames[] = {
51 "kernel_arg_addr_space",
52 "kernel_arg_access_qual",
53 "kernel_arg_type",
54 "kernel_arg_base_type",
55 "kernel_arg_type_qual"};
56static const unsigned NumKernelArgMDNodes = 5;
57
58namespace {
59
60using MDVector = SmallVector<Metadata *, 8>;
61struct KernelArgMD {
62 MDVector ArgVector[NumKernelArgMDNodes];
63};
64
65} // end anonymous namespace
66
67static inline bool
68IsImageType(StringRef TypeString) {
69 return TypeString == "image2d_t" || TypeString == "image3d_t";
70}
71
72static inline bool
73IsSamplerType(StringRef TypeString) {
74 return TypeString == "sampler_t";
75}
76
77static Function *
78GetFunctionFromMDNode(MDNode *Node) {
79 if (!Node)
80 return nullptr;
81
82 size_t NumOps = Node->getNumOperands();
83 if (NumOps != NumKernelArgMDNodes + 1)
84 return nullptr;
85
86 auto *F = mdconst::dyn_extract<Function>(MD: Node->getOperand(I: 0));
87 if (!F)
88 return nullptr;
89
90 // Validation checks.
91 size_t ExpectNumArgNodeOps = F->arg_size() + 1;
92 for (size_t i = 0; i < NumKernelArgMDNodes; ++i) {
93 MDNode *ArgNode = dyn_cast_or_null<MDNode>(Val: Node->getOperand(I: i + 1));
94 if (ArgNode->getNumOperands() != ExpectNumArgNodeOps)
95 return nullptr;
96 if (!ArgNode->getOperand(I: 0))
97 return nullptr;
98
99 // FIXME: It should be possible to do image lowering when some metadata
100 // args missing or not in the expected order.
101 MDString *StringNode = dyn_cast<MDString>(Val: ArgNode->getOperand(I: 0));
102 if (!StringNode || StringNode->getString() != KernelArgMDNodeNames[i])
103 return nullptr;
104 }
105
106 return F;
107}
108
109static StringRef
110AccessQualFromMD(MDNode *KernelMDNode, unsigned ArgIdx) {
111 MDNode *ArgAQNode = cast<MDNode>(Val: KernelMDNode->getOperand(I: 2));
112 return cast<MDString>(Val: ArgAQNode->getOperand(I: ArgIdx + 1))->getString();
113}
114
115static StringRef
116ArgTypeFromMD(MDNode *KernelMDNode, unsigned ArgIdx) {
117 MDNode *ArgTypeNode = cast<MDNode>(Val: KernelMDNode->getOperand(I: 3));
118 return cast<MDString>(Val: ArgTypeNode->getOperand(I: ArgIdx + 1))->getString();
119}
120
121static MDVector
122GetArgMD(MDNode *KernelMDNode, unsigned OpIdx) {
123 MDVector Res;
124 for (unsigned i = 0; i < NumKernelArgMDNodes; ++i) {
125 MDNode *Node = cast<MDNode>(Val: KernelMDNode->getOperand(I: i + 1));
126 Res.push_back(Elt: Node->getOperand(I: OpIdx));
127 }
128 return Res;
129}
130
131static void
132PushArgMD(KernelArgMD &MD, const MDVector &V) {
133 assert(V.size() == NumKernelArgMDNodes);
134 for (unsigned i = 0; i < NumKernelArgMDNodes; ++i) {
135 MD.ArgVector[i].push_back(Elt: V[i]);
136 }
137}
138
139namespace {
140
141class R600OpenCLImageTypeLoweringPass : public ModulePass {
142 static char ID;
143
144 LLVMContext *Context;
145 Type *Int32Type;
146 Type *ImageSizeType;
147 Type *ImageFormatType;
148 SmallVector<Instruction *, 4> InstsToErase;
149
150 bool replaceImageUses(Argument &ImageArg, uint32_t ResourceID,
151 Argument &ImageSizeArg,
152 Argument &ImageFormatArg) {
153 bool Modified = false;
154
155 for (auto &Use : ImageArg.uses()) {
156 auto *Inst = dyn_cast<CallInst>(Val: Use.getUser());
157 if (!Inst) {
158 continue;
159 }
160
161 Function *F = Inst->getCalledFunction();
162 if (!F)
163 continue;
164
165 Value *Replacement = nullptr;
166 StringRef Name = F->getName();
167 if (Name.starts_with(Prefix: GetImageResourceIDFunc)) {
168 Replacement = ConstantInt::get(Ty: Int32Type, V: ResourceID);
169 } else if (Name.starts_with(Prefix: GetImageSizeFunc)) {
170 Replacement = &ImageSizeArg;
171 } else if (Name.starts_with(Prefix: GetImageFormatFunc)) {
172 Replacement = &ImageFormatArg;
173 } else {
174 continue;
175 }
176
177 Inst->replaceAllUsesWith(V: Replacement);
178 InstsToErase.push_back(Elt: Inst);
179 Modified = true;
180 }
181
182 return Modified;
183 }
184
185 bool replaceSamplerUses(Argument &SamplerArg, uint32_t ResourceID) {
186 bool Modified = false;
187
188 for (const auto &Use : SamplerArg.uses()) {
189 auto *Inst = dyn_cast<CallInst>(Val: Use.getUser());
190 if (!Inst) {
191 continue;
192 }
193
194 Function *F = Inst->getCalledFunction();
195 if (!F)
196 continue;
197
198 Value *Replacement = nullptr;
199 StringRef Name = F->getName();
200 if (Name == GetSamplerResourceIDFunc) {
201 Replacement = ConstantInt::get(Ty: Int32Type, V: ResourceID);
202 } else {
203 continue;
204 }
205
206 Inst->replaceAllUsesWith(V: Replacement);
207 InstsToErase.push_back(Elt: Inst);
208 Modified = true;
209 }
210
211 return Modified;
212 }
213
214 bool replaceImageAndSamplerUses(Function *F, MDNode *KernelMDNode) {
215 uint32_t NumReadOnlyImageArgs = 0;
216 uint32_t NumWriteOnlyImageArgs = 0;
217 uint32_t NumSamplerArgs = 0;
218
219 bool Modified = false;
220 InstsToErase.clear();
221 for (auto *ArgI = F->arg_begin(); ArgI != F->arg_end(); ++ArgI) {
222 Argument &Arg = *ArgI;
223 StringRef Type = ArgTypeFromMD(KernelMDNode, ArgIdx: Arg.getArgNo());
224
225 // Handle image types.
226 if (IsImageType(TypeString: Type)) {
227 StringRef AccessQual = AccessQualFromMD(KernelMDNode, ArgIdx: Arg.getArgNo());
228 uint32_t ResourceID;
229 if (AccessQual == "read_only") {
230 ResourceID = NumReadOnlyImageArgs++;
231 } else if (AccessQual == "write_only") {
232 ResourceID = NumWriteOnlyImageArgs++;
233 } else {
234 llvm_unreachable("Wrong image access qualifier.");
235 }
236
237 Argument &SizeArg = *(++ArgI);
238 Argument &FormatArg = *(++ArgI);
239 Modified |= replaceImageUses(ImageArg&: Arg, ResourceID, ImageSizeArg&: SizeArg, ImageFormatArg&: FormatArg);
240
241 // Handle sampler type.
242 } else if (IsSamplerType(TypeString: Type)) {
243 uint32_t ResourceID = NumSamplerArgs++;
244 Modified |= replaceSamplerUses(SamplerArg&: Arg, ResourceID);
245 }
246 }
247 for (auto *Inst : InstsToErase)
248 Inst->eraseFromParent();
249
250 return Modified;
251 }
252
253 std::tuple<Function *, MDNode *>
254 addImplicitArgs(Function *F, MDNode *KernelMDNode) {
255 bool Modified = false;
256
257 FunctionType *FT = F->getFunctionType();
258 SmallVector<Type *, 8> ArgTypes;
259
260 // Metadata operands for new MDNode.
261 KernelArgMD NewArgMDs;
262 PushArgMD(MD&: NewArgMDs, V: GetArgMD(KernelMDNode, OpIdx: 0));
263
264 // Add implicit arguments to the signature.
265 for (unsigned i = 0; i < FT->getNumParams(); ++i) {
266 ArgTypes.push_back(Elt: FT->getParamType(i));
267 MDVector ArgMD = GetArgMD(KernelMDNode, OpIdx: i + 1);
268 PushArgMD(MD&: NewArgMDs, V: ArgMD);
269
270 if (!IsImageType(TypeString: ArgTypeFromMD(KernelMDNode, ArgIdx: i)))
271 continue;
272
273 // Add size implicit argument.
274 ArgTypes.push_back(Elt: ImageSizeType);
275 ArgMD[2] = ArgMD[3] = MDString::get(Context&: *Context, Str: ImageSizeArgMDType);
276 PushArgMD(MD&: NewArgMDs, V: ArgMD);
277
278 // Add format implicit argument.
279 ArgTypes.push_back(Elt: ImageFormatType);
280 ArgMD[2] = ArgMD[3] = MDString::get(Context&: *Context, Str: ImageFormatArgMDType);
281 PushArgMD(MD&: NewArgMDs, V: ArgMD);
282
283 Modified = true;
284 }
285 if (!Modified) {
286 return std::tuple(nullptr, nullptr);
287 }
288
289 // Create function with new signature and clone the old body into it.
290 auto *NewFT = FunctionType::get(Result: FT->getReturnType(), Params: ArgTypes, isVarArg: false);
291 auto *NewF = Function::Create(Ty: NewFT, Linkage: F->getLinkage(), N: F->getName());
292 ValueToValueMapTy VMap;
293 auto *NewFArgIt = NewF->arg_begin();
294 for (auto &Arg: F->args()) {
295 auto ArgName = Arg.getName();
296 NewFArgIt->setName(ArgName);
297 VMap[&Arg] = &(*NewFArgIt++);
298 if (IsImageType(TypeString: ArgTypeFromMD(KernelMDNode, ArgIdx: Arg.getArgNo()))) {
299 (NewFArgIt++)->setName(Twine("__size_") + ArgName);
300 (NewFArgIt++)->setName(Twine("__format_") + ArgName);
301 }
302 }
303 SmallVector<ReturnInst*, 8> Returns;
304 CloneFunctionInto(NewFunc: NewF, OldFunc: F, VMap, Changes: CloneFunctionChangeType::LocalChangesOnly,
305 Returns);
306
307 // Build new MDNode.
308 SmallVector<Metadata *, 6> KernelMDArgs;
309 KernelMDArgs.push_back(Elt: ConstantAsMetadata::get(C: NewF));
310 for (const MDVector &MDV : NewArgMDs.ArgVector)
311 KernelMDArgs.push_back(Elt: MDNode::get(Context&: *Context, MDs: MDV));
312 MDNode *NewMDNode = MDNode::get(Context&: *Context, MDs: KernelMDArgs);
313
314 return std::tuple(NewF, NewMDNode);
315 }
316
317 bool transformKernels(Module &M) {
318 NamedMDNode *KernelsMDNode = M.getNamedMetadata(Name: KernelsMDNodeName);
319 if (!KernelsMDNode)
320 return false;
321
322 bool Modified = false;
323 for (unsigned i = 0; i < KernelsMDNode->getNumOperands(); ++i) {
324 MDNode *KernelMDNode = KernelsMDNode->getOperand(i);
325 Function *F = GetFunctionFromMDNode(Node: KernelMDNode);
326 if (!F)
327 continue;
328
329 Function *NewF;
330 MDNode *NewMDNode;
331 std::tie(args&: NewF, args&: NewMDNode) = addImplicitArgs(F, KernelMDNode);
332 if (NewF) {
333 // Replace old function and metadata with new ones.
334 F->eraseFromParent();
335 M.getFunctionList().push_back(val: NewF);
336 M.getOrInsertFunction(Name: NewF->getName(), T: NewF->getFunctionType(),
337 AttributeList: NewF->getAttributes());
338 KernelsMDNode->setOperand(I: i, New: NewMDNode);
339
340 F = NewF;
341 KernelMDNode = NewMDNode;
342 Modified = true;
343 }
344
345 Modified |= replaceImageAndSamplerUses(F, KernelMDNode);
346 }
347
348 return Modified;
349 }
350
351public:
352 R600OpenCLImageTypeLoweringPass() : ModulePass(ID) {}
353
354 bool runOnModule(Module &M) override {
355 Context = &M.getContext();
356 Int32Type = Type::getInt32Ty(C&: M.getContext());
357 ImageSizeType = ArrayType::get(ElementType: Int32Type, NumElements: 3);
358 ImageFormatType = ArrayType::get(ElementType: Int32Type, NumElements: 2);
359
360 return transformKernels(M);
361 }
362
363 StringRef getPassName() const override {
364 return "R600 OpenCL Image Type Pass";
365 }
366};
367
368} // end anonymous namespace
369
370char R600OpenCLImageTypeLoweringPass::ID = 0;
371
372ModulePass *llvm::createR600OpenCLImageTypeLoweringPass() {
373 return new R600OpenCLImageTypeLoweringPass();
374}
375