| 1 | //===- WebAssemblyTargetMachine.cpp - Define TargetMachine for WebAssembly -==// |
| 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 file defines the WebAssembly-specific subclass of TargetMachine. |
| 11 | /// |
| 12 | //===----------------------------------------------------------------------===// |
| 13 | |
| 14 | #include "WebAssemblyTargetMachine.h" |
| 15 | #include "MCTargetDesc/WebAssemblyMCTargetDesc.h" |
| 16 | #include "TargetInfo/WebAssemblyTargetInfo.h" |
| 17 | #include "WebAssembly.h" |
| 18 | #include "WebAssemblyISelLowering.h" |
| 19 | #include "WebAssemblyMachineFunctionInfo.h" |
| 20 | #include "WebAssemblyTargetObjectFile.h" |
| 21 | #include "WebAssemblyTargetTransformInfo.h" |
| 22 | #include "WebAssemblyUtilities.h" |
| 23 | #include "llvm/CodeGen/GlobalISel/IRTranslator.h" |
| 24 | #include "llvm/CodeGen/GlobalISel/InstructionSelect.h" |
| 25 | #include "llvm/CodeGen/GlobalISel/Legalizer.h" |
| 26 | #include "llvm/CodeGen/GlobalISel/RegBankSelect.h" |
| 27 | #include "llvm/CodeGen/MIRParser/MIParser.h" |
| 28 | #include "llvm/CodeGen/Passes.h" |
| 29 | #include "llvm/CodeGen/RegAllocRegistry.h" |
| 30 | #include "llvm/CodeGen/TargetPassConfig.h" |
| 31 | #include "llvm/IR/Function.h" |
| 32 | #include "llvm/InitializePasses.h" |
| 33 | #include "llvm/MC/TargetRegistry.h" |
| 34 | #include "llvm/Support/Compiler.h" |
| 35 | #include "llvm/Target/TargetOptions.h" |
| 36 | #include "llvm/Transforms/Scalar.h" |
| 37 | #include "llvm/Transforms/Utils.h" |
| 38 | #include <optional> |
| 39 | using namespace llvm; |
| 40 | |
| 41 | #define DEBUG_TYPE "wasm" |
| 42 | |
| 43 | // A command-line option to keep implicit locals |
| 44 | // for the purpose of testing with lit/llc ONLY. |
| 45 | // This produces output which is not valid WebAssembly, and is not supported |
| 46 | // by assemblers/disassemblers and other MC based tools. |
| 47 | cl::opt<bool> WebAssembly::WasmDisableExplicitLocals( |
| 48 | "wasm-disable-explicit-locals" , cl::Hidden, |
| 49 | cl::desc("WebAssembly: output implicit locals in" |
| 50 | " instruction output for test purposes only." ), |
| 51 | cl::init(Val: false)); |
| 52 | |
| 53 | // Exception handling & setjmp-longjmp handling related options. |
| 54 | |
| 55 | // Emscripten's asm.js-style setjmp/longjmp handling |
| 56 | cl::opt<bool> WebAssembly::WasmEnableEmSjLj( |
| 57 | "enable-emscripten-sjlj" , |
| 58 | cl::desc("WebAssembly Emscripten-style setjmp/longjmp handling" ), |
| 59 | cl::init(Val: false)); |
| 60 | // Exception handling using wasm EH instructions |
| 61 | cl::opt<bool> |
| 62 | WebAssembly::WasmEnableEH("wasm-enable-eh" , |
| 63 | cl::desc("WebAssembly exception handling" )); |
| 64 | // setjmp/longjmp handling using wasm EH instructions |
| 65 | cl::opt<bool> WebAssembly::WasmEnableSjLj( |
| 66 | "wasm-enable-sjlj" , cl::desc("WebAssembly setjmp/longjmp handling" )); |
| 67 | // If true, use the legacy Wasm EH proposal: |
| 68 | // https://github.com/WebAssembly/exception-handling/blob/main/proposals/exception-handling/legacy/Exceptions.md |
| 69 | // And if false, use the standardized Wasm EH proposal: |
| 70 | // https://github.com/WebAssembly/exception-handling/blob/main/proposals/exception-handling/Exceptions.md |
| 71 | // Currently set to true by default because not all major web browsers turn on |
| 72 | // the new standard proposal by default, but will later change to false. |
| 73 | cl::opt<bool> WebAssembly::WasmUseLegacyEH( |
| 74 | "wasm-use-legacy-eh" , cl::desc("WebAssembly exception handling (legacy)" ), |
| 75 | cl::init(Val: true)); |
| 76 | |
| 77 | extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void |
| 78 | LLVMInitializeWebAssemblyTarget() { |
| 79 | // Register the target. |
| 80 | RegisterTargetMachine<WebAssemblyTargetMachine> X( |
| 81 | getTheWebAssemblyTarget32()); |
| 82 | RegisterTargetMachine<WebAssemblyTargetMachine> Y( |
| 83 | getTheWebAssemblyTarget64()); |
| 84 | |
| 85 | // Register backend passes |
| 86 | auto &PR = *PassRegistry::getPassRegistry(); |
| 87 | initializeGlobalISel(PR); |
| 88 | initializeWebAssemblyPreLegalizerCombinerLegacyPass(PR); |
| 89 | initializeWebAssemblyPostLegalizerCombinerLegacyPass(PR); |
| 90 | initializeWebAssemblyAddMissingPrototypesLegacyPass(PR); |
| 91 | initializeWebAssemblyLowerEmscriptenEHSjLjLegacyPass(PR); |
| 92 | initializeLowerGlobalDtorsLegacyPassPass(PR); |
| 93 | initializeWebAssemblyFixFunctionBitcastsLegacyPass(PR); |
| 94 | initializeWebAssemblyOptimizeReturnedLegacyPass(PR); |
| 95 | initializeWebAssemblyRefTypeMem2LocalLegacyPass(PR); |
| 96 | initializeWebAssemblyArgumentMoveLegacyPass(PR); |
| 97 | initializeWebAssemblyAsmPrinterPass(PR); |
| 98 | initializeWebAssemblySetP2AlignOperandsLegacyPass(PR); |
| 99 | initializeWebAssemblyReplacePhysRegsLegacyPass(PR); |
| 100 | initializeWebAssemblyOptimizeLiveIntervalsLegacyPass(PR); |
| 101 | initializeWebAssemblyMemIntrinsicResultsLegacyPass(PR); |
| 102 | initializeWebAssemblyRegStackifyLegacyPass(PR); |
| 103 | initializeWebAssemblyRegColoringLegacyPass(PR); |
| 104 | initializeWebAssemblyNullifyDebugValueListsLegacyPass(PR); |
| 105 | initializeWebAssemblyFixIrreducibleControlFlowLegacyPass(PR); |
| 106 | initializeWebAssemblyLateEHPrepareLegacyPass(PR); |
| 107 | initializeWebAssemblyExceptionInfoWrapperPassPass(PR); |
| 108 | initializeWebAssemblyCFGSortLegacyPass(PR); |
| 109 | initializeWebAssemblyCFGStackifyLegacyPass(PR); |
| 110 | initializeWebAssemblyExplicitLocalsLegacyPass(PR); |
| 111 | initializeWebAssemblyLowerBrUnlessLegacyPass(PR); |
| 112 | initializeWebAssemblyRegNumberingLegacyPass(PR); |
| 113 | initializeWebAssemblyDebugFixupLegacyPass(PR); |
| 114 | initializeWebAssemblyPeepholeLegacyPass(PR); |
| 115 | initializeWebAssemblyMCLowerPreLegacyPass(PR); |
| 116 | initializeWebAssemblyFixBrTableDefaultsLegacyPass(PR); |
| 117 | initializeWebAssemblyDAGToDAGISelLegacyPass(PR); |
| 118 | } |
| 119 | |
| 120 | //===----------------------------------------------------------------------===// |
| 121 | // WebAssembly Lowering public interface. |
| 122 | //===----------------------------------------------------------------------===// |
| 123 | |
| 124 | static Reloc::Model getEffectiveRelocModel(std::optional<Reloc::Model> RM) { |
| 125 | // Default to static relocation model. This should always be more optimal |
| 126 | // than PIC since the static linker can determine all global addresses and |
| 127 | // assume direct function calls. |
| 128 | return RM.value_or(u: Reloc::Static); |
| 129 | } |
| 130 | |
| 131 | using WebAssembly::WasmDisableExplicitLocals; |
| 132 | using WebAssembly::WasmEnableEH; |
| 133 | using WebAssembly::WasmEnableEmSjLj; |
| 134 | using WebAssembly::WasmEnableSjLj; |
| 135 | |
| 136 | static void basicCheckForEHAndSjLj(TargetMachine *TM) { |
| 137 | |
| 138 | bool EnableEmEH = TM->Options.ExceptionModel == ExceptionHandling::Emscripten; |
| 139 | |
| 140 | // You can't enable two modes of EH at the same time |
| 141 | if (EnableEmEH && WasmEnableEH) |
| 142 | report_fatal_error( |
| 143 | reason: "-exception-model=emscripten not allowed with -wasm-enable-eh" ); |
| 144 | // You can't enable two modes of SjLj at the same time |
| 145 | if (WasmEnableEmSjLj && WasmEnableSjLj) |
| 146 | report_fatal_error( |
| 147 | reason: "-enable-emscripten-sjlj not allowed with -wasm-enable-sjlj" ); |
| 148 | // You can't mix Emscripten EH with Wasm SjLj. |
| 149 | if (EnableEmEH && WasmEnableSjLj) |
| 150 | report_fatal_error( |
| 151 | reason: "-exception-model=emscripten not allowed with -wasm-enable-sjlj" ); |
| 152 | |
| 153 | if (TM->Options.ExceptionModel == ExceptionHandling::Default) { |
| 154 | // FIXME: These flags should be removed in favor of directly using the |
| 155 | // generically configured ExceptionsType |
| 156 | if (WebAssembly::WasmEnableEH || WebAssembly::WasmEnableSjLj) |
| 157 | TM->Options.ExceptionModel = ExceptionHandling::Wasm; |
| 158 | } |
| 159 | |
| 160 | // Basic Correctness checking related to -exception-model |
| 161 | if (TM->Options.ExceptionModel != ExceptionHandling::Default && |
| 162 | TM->Options.ExceptionModel != ExceptionHandling::None && |
| 163 | TM->Options.ExceptionModel != ExceptionHandling::Wasm && |
| 164 | TM->Options.ExceptionModel != ExceptionHandling::Emscripten) |
| 165 | report_fatal_error( |
| 166 | reason: "-exception-model should be either 'none', 'wasm', or 'emscripten'" ); |
| 167 | if (WasmEnableEH && TM->Options.ExceptionModel != ExceptionHandling::Wasm) |
| 168 | report_fatal_error( |
| 169 | reason: "-wasm-enable-eh only allowed with -exception-model=wasm" ); |
| 170 | if (WasmEnableSjLj && TM->Options.ExceptionModel != ExceptionHandling::Wasm) |
| 171 | report_fatal_error( |
| 172 | reason: "-wasm-enable-sjlj only allowed with -exception-model=wasm" ); |
| 173 | if ((!WasmEnableEH && !WasmEnableSjLj) && |
| 174 | TM->Options.ExceptionModel == ExceptionHandling::Wasm) |
| 175 | report_fatal_error( |
| 176 | reason: "-exception-model=wasm only allowed with at least one of " |
| 177 | "-wasm-enable-eh or -wasm-enable-sjlj" ); |
| 178 | |
| 179 | // Currently it is allowed to mix Wasm EH with Emscripten SjLj as an interim |
| 180 | // measure, but some code will error out at compile time in this combination. |
| 181 | // See WebAssemblyLowerEmscriptenEHSjLj pass for details. |
| 182 | } |
| 183 | |
| 184 | /// Create an WebAssembly architecture model. |
| 185 | /// |
| 186 | WebAssemblyTargetMachine::WebAssemblyTargetMachine( |
| 187 | const Target &T, const Triple &TT, StringRef CPU, StringRef FS, |
| 188 | const TargetOptions &Options, std::optional<Reloc::Model> RM, |
| 189 | std::optional<CodeModel::Model> CM, CodeGenOptLevel OL, bool JIT) |
| 190 | : CodeGenTargetMachineImpl(T, TT.computeDataLayout(), TT, CPU, FS, Options, |
| 191 | getEffectiveRelocModel(RM), |
| 192 | getEffectiveCodeModel(CM, Default: CodeModel::Large), OL), |
| 193 | TLOF(new WebAssemblyTargetObjectFile()), |
| 194 | UsesMultivalueABI(Options.MCOptions.getABIName() == "experimental-mv" ) { |
| 195 | // WebAssembly type-checks instructions, but a noreturn function with a return |
| 196 | // type that doesn't match the context will cause a check failure. So we lower |
| 197 | // LLVM 'unreachable' to ISD::TRAP and then lower that to WebAssembly's |
| 198 | // 'unreachable' instructions which is meant for that case. Formerly, we also |
| 199 | // needed to add checks to SP failure emission in the instruction selection |
| 200 | // backends, but this has since been tied to TrapUnreachable and is no longer |
| 201 | // necessary. |
| 202 | this->Options.TrapUnreachable = true; |
| 203 | this->Options.NoTrapAfterNoreturn = false; |
| 204 | |
| 205 | // WebAssembly treats each function as an independent unit. Force |
| 206 | // -ffunction-sections, effectively, so that we can emit them independently. |
| 207 | this->Options.FunctionSections = true; |
| 208 | this->Options.DataSections = true; |
| 209 | this->Options.UniqueSectionNames = true; |
| 210 | |
| 211 | basicCheckForEHAndSjLj(TM: this); |
| 212 | initAsmInfo(); |
| 213 | |
| 214 | LLT::setUseExtended(true); |
| 215 | |
| 216 | // Note that we don't use setRequiresStructuredCFG(true). It disables |
| 217 | // optimizations than we're ok with, and want, such as critical edge |
| 218 | // splitting and tail merging. |
| 219 | } |
| 220 | |
| 221 | WebAssemblyTargetMachine::~WebAssemblyTargetMachine() = default; // anchor. |
| 222 | |
| 223 | const WebAssemblySubtarget * |
| 224 | WebAssemblyTargetMachine::getSubtargetImpl(StringRef CPU, StringRef FS) const { |
| 225 | auto &I = SubtargetMap[CPU.str() + FS.str()]; |
| 226 | if (!I) { |
| 227 | I = std::make_unique<WebAssemblySubtarget>(args: TargetTriple, args&: CPU, args&: FS, args: *this); |
| 228 | } |
| 229 | return I.get(); |
| 230 | } |
| 231 | |
| 232 | const WebAssemblySubtarget * |
| 233 | WebAssemblyTargetMachine::getSubtargetImpl(const Function &F) const { |
| 234 | Attribute CPUAttr = F.getFnAttribute(Kind: "target-cpu" ); |
| 235 | Attribute FSAttr = F.getFnAttribute(Kind: "target-features" ); |
| 236 | |
| 237 | StringRef CPU = CPUAttr.isValid() ? CPUAttr.getValueAsString() : TargetCPU; |
| 238 | StringRef FS = FSAttr.isValid() ? FSAttr.getValueAsString() : TargetFS; |
| 239 | |
| 240 | return getSubtargetImpl(CPU, FS); |
| 241 | } |
| 242 | |
| 243 | namespace { |
| 244 | |
| 245 | /// WebAssembly Code Generator Pass Configuration Options. |
| 246 | class WebAssemblyPassConfig final : public TargetPassConfig { |
| 247 | public: |
| 248 | WebAssemblyPassConfig(WebAssemblyTargetMachine &TM, PassManagerBase &PM) |
| 249 | : TargetPassConfig(TM, PM) {} |
| 250 | |
| 251 | WebAssemblyTargetMachine &getWebAssemblyTargetMachine() const { |
| 252 | return getTM<WebAssemblyTargetMachine>(); |
| 253 | } |
| 254 | |
| 255 | FunctionPass *createTargetRegisterAllocator(bool) override; |
| 256 | |
| 257 | void addIRPasses() override; |
| 258 | void addISelPrepare() override; |
| 259 | bool addInstSelector() override; |
| 260 | void addOptimizedRegAlloc() override; |
| 261 | void addPostRegAlloc() override; |
| 262 | bool addGCPasses() override { return false; } |
| 263 | void addPreEmitPass() override; |
| 264 | bool addPreISel() override; |
| 265 | |
| 266 | // No reg alloc |
| 267 | bool addRegAssignAndRewriteFast() override { return false; } |
| 268 | |
| 269 | // No reg alloc |
| 270 | bool addRegAssignAndRewriteOptimized() override { return false; } |
| 271 | |
| 272 | bool addIRTranslator() override; |
| 273 | void addPreLegalizeMachineIR() override; |
| 274 | bool addLegalizeMachineIR() override; |
| 275 | void addPreRegBankSelect() override; |
| 276 | bool addRegBankSelect() override; |
| 277 | bool addGlobalInstructionSelect() override; |
| 278 | }; |
| 279 | } // end anonymous namespace |
| 280 | |
| 281 | MachineFunctionInfo *WebAssemblyTargetMachine::createMachineFunctionInfo( |
| 282 | BumpPtrAllocator &Allocator, const Function &F, |
| 283 | const TargetSubtargetInfo *STI) const { |
| 284 | return WebAssemblyFunctionInfo::create<WebAssemblyFunctionInfo>(Allocator, F, |
| 285 | STI); |
| 286 | } |
| 287 | |
| 288 | TargetTransformInfo |
| 289 | WebAssemblyTargetMachine::getTargetTransformInfo(const Function &F) const { |
| 290 | return TargetTransformInfo(std::make_unique<WebAssemblyTTIImpl>(args: this, args: F)); |
| 291 | } |
| 292 | |
| 293 | TargetPassConfig * |
| 294 | WebAssemblyTargetMachine::createPassConfig(PassManagerBase &PM) { |
| 295 | return new WebAssemblyPassConfig(*this, PM); |
| 296 | } |
| 297 | |
| 298 | FunctionPass *WebAssemblyPassConfig::createTargetRegisterAllocator(bool) { |
| 299 | return nullptr; // No reg alloc |
| 300 | } |
| 301 | |
| 302 | //===----------------------------------------------------------------------===// |
| 303 | // The following functions are called from lib/CodeGen/Passes.cpp to modify |
| 304 | // the CodeGen pass sequence. |
| 305 | //===----------------------------------------------------------------------===// |
| 306 | |
| 307 | void WebAssemblyPassConfig::addIRPasses() { |
| 308 | // Add signatures to prototype-less function declarations |
| 309 | addPass(P: createWebAssemblyAddMissingPrototypesLegacyPass()); |
| 310 | |
| 311 | // Lower .llvm.global_dtors into .llvm.global_ctors with __cxa_atexit calls. |
| 312 | addPass(P: createLowerGlobalDtorsLegacyPass()); |
| 313 | |
| 314 | // Fix function bitcasts, as WebAssembly requires caller and callee signatures |
| 315 | // to match. |
| 316 | addPass(P: createWebAssemblyFixFunctionBitcastsLegacyPass()); |
| 317 | |
| 318 | // Optimize "returned" function attributes. |
| 319 | if (getOptLevel() != CodeGenOptLevel::None) |
| 320 | addPass(P: createWebAssemblyOptimizeReturnedLegacyPass()); |
| 321 | |
| 322 | // If exception handling is not enabled and setjmp/longjmp handling is |
| 323 | // enabled, we lower invokes into calls and delete unreachable landingpad |
| 324 | // blocks. Lowering invokes when there is no EH support is done in |
| 325 | // TargetPassConfig::addPassesToHandleExceptions, but that runs after these IR |
| 326 | // passes and Emscripten SjLj handling expects all invokes to be lowered |
| 327 | // before. |
| 328 | bool EnableEmEH = TM->Options.ExceptionModel == ExceptionHandling::Emscripten; |
| 329 | if (!EnableEmEH && !WasmEnableEH) { |
| 330 | addPass(P: createLowerInvokePass()); |
| 331 | // The lower invoke pass may create unreachable code. Remove it in order not |
| 332 | // to process dead blocks in setjmp/longjmp handling. |
| 333 | addPass(P: createUnreachableBlockEliminationPass()); |
| 334 | } |
| 335 | |
| 336 | // Handle exceptions and setjmp/longjmp if enabled. Unlike Wasm EH preparation |
| 337 | // done in WasmEHPrepare pass, Wasm SjLj preparation shares libraries and |
| 338 | // transformation algorithms with Emscripten SjLj, so we run |
| 339 | // LowerEmscriptenEHSjLj pass also when Wasm SjLj is enabled. |
| 340 | if (EnableEmEH || WasmEnableEmSjLj || WasmEnableSjLj) |
| 341 | addPass(P: createWebAssemblyLowerEmscriptenEHSjLjLegacyPass(EnableEmEH)); |
| 342 | |
| 343 | // Expand indirectbr instructions to switches. |
| 344 | addPass(P: createIndirectBrExpandPass()); |
| 345 | |
| 346 | // Try to expand `vecreduce_{and, or}` into `{any, all}_true`. |
| 347 | addPass(P: createWebAssemblyReduceToAnyAllTrueLegacyPass( |
| 348 | TM&: getWebAssemblyTargetMachine())); |
| 349 | |
| 350 | TargetPassConfig::addIRPasses(); |
| 351 | } |
| 352 | |
| 353 | void WebAssemblyPassConfig::addISelPrepare() { |
| 354 | // We need to move reference type allocas to WASM_ADDRESS_SPACE_VAR so that |
| 355 | // loads and stores are promoted to local.gets/local.sets. |
| 356 | addPass(P: createWebAssemblyRefTypeMem2LocalLegacyPass()); |
| 357 | // Lower atomics and TLS if necessary |
| 358 | addPass(P: createWebAssemblyCoalesceFeaturesAndStripAtomicsLegacyPass( |
| 359 | TM&: getWebAssemblyTargetMachine())); |
| 360 | |
| 361 | // This is a no-op if atomics are not used in the module |
| 362 | addPass(P: createAtomicExpandLegacyPass()); |
| 363 | |
| 364 | TargetPassConfig::addISelPrepare(); |
| 365 | } |
| 366 | |
| 367 | bool WebAssemblyPassConfig::addInstSelector() { |
| 368 | (void)TargetPassConfig::addInstSelector(); |
| 369 | addPass(P: createWebAssemblyISelDagLegacyPass(TM&: getWebAssemblyTargetMachine(), |
| 370 | OptLevel: getOptLevel())); |
| 371 | // Run the argument-move pass immediately after the ScheduleDAG scheduler |
| 372 | // so that we can fix up the ARGUMENT instructions before anything else |
| 373 | // sees them in the wrong place. |
| 374 | addPass(P: createWebAssemblyArgumentMoveLegacyPass()); |
| 375 | // Set the p2align operands. This information is present during ISel, however |
| 376 | // it's inconvenient to collect. Collect it now, and update the immediate |
| 377 | // operands. |
| 378 | addPass(P: createWebAssemblySetP2AlignOperandsLegacyPass()); |
| 379 | |
| 380 | // Eliminate range checks and add default targets to br_table instructions. |
| 381 | addPass(P: createWebAssemblyFixBrTableDefaultsLegacyPass()); |
| 382 | |
| 383 | // unreachable is terminator, non-terminator instruction after it is not |
| 384 | // allowed. |
| 385 | addPass(P: createWebAssemblyCleanCodeAfterTrapLegacyPass()); |
| 386 | |
| 387 | return false; |
| 388 | } |
| 389 | |
| 390 | void WebAssemblyPassConfig::addOptimizedRegAlloc() { |
| 391 | // Currently RegisterCoalesce degrades wasm debug info quality by a |
| 392 | // significant margin. As a quick fix, disable this for -O1, which is often |
| 393 | // used for debugging large applications. Disabling this increases code size |
| 394 | // of Emscripten core benchmarks by ~5%, which is acceptable for -O1, which is |
| 395 | // usually not used for production builds. |
| 396 | // TODO Investigate why RegisterCoalesce degrades debug info quality and fix |
| 397 | // it properly |
| 398 | if (getOptLevel() == CodeGenOptLevel::Less) |
| 399 | disablePass(PassID: &RegisterCoalescerID); |
| 400 | TargetPassConfig::addOptimizedRegAlloc(); |
| 401 | } |
| 402 | |
| 403 | void WebAssemblyPassConfig::addPostRegAlloc() { |
| 404 | // TODO: The following CodeGen passes don't currently support code containing |
| 405 | // virtual registers. Consider removing their restrictions and re-enabling |
| 406 | // them. |
| 407 | |
| 408 | // These functions all require the NoVRegs property. |
| 409 | disablePass(PassID: &MachineLateInstrsCleanupID); |
| 410 | disablePass(PassID: &MachineCopyPropagationID); |
| 411 | disablePass(PassID: &PostRAMachineSinkingID); |
| 412 | disablePass(PassID: &PostRASchedulerID); |
| 413 | disablePass(PassID: &FuncletLayoutID); |
| 414 | disablePass(PassID: &StackMapLivenessID); |
| 415 | disablePass(PassID: &PatchableFunctionID); |
| 416 | disablePass(PassID: &ShrinkWrapID); |
| 417 | disablePass(PassID: &RemoveLoadsIntoFakeUsesID); |
| 418 | |
| 419 | // This pass hurts code size for wasm because it can generate irreducible |
| 420 | // control flow. |
| 421 | disablePass(PassID: &MachineBlockPlacementID); |
| 422 | |
| 423 | TargetPassConfig::addPostRegAlloc(); |
| 424 | } |
| 425 | |
| 426 | void WebAssemblyPassConfig::addPreEmitPass() { |
| 427 | TargetPassConfig::addPreEmitPass(); |
| 428 | |
| 429 | // Nullify DBG_VALUE_LISTs that we cannot handle. |
| 430 | addPass(P: createWebAssemblyNullifyDebugValueListsLegacyPass()); |
| 431 | |
| 432 | // Remove any unreachable blocks that may be left floating around. |
| 433 | // Rare, but possible. Needed for WebAssemblyFixIrreducibleControlFlow. |
| 434 | addPass(PassID: &UnreachableMachineBlockElimID); |
| 435 | |
| 436 | // Eliminate multiple-entry loops. |
| 437 | addPass(P: createWebAssemblyFixIrreducibleControlFlowLegacyPass()); |
| 438 | |
| 439 | // Do various transformations for exception handling. |
| 440 | // Every CFG-changing optimizations should come before this. |
| 441 | if (TM->Options.ExceptionModel == ExceptionHandling::Wasm) |
| 442 | addPass(P: createWebAssemblyLateEHPrepareLegacyPass()); |
| 443 | |
| 444 | // Now that we have a prologue and epilogue and all frame indices are |
| 445 | // rewritten, eliminate SP and FP. This allows them to be stackified, |
| 446 | // colored, and numbered with the rest of the registers. |
| 447 | addPass(P: createWebAssemblyReplacePhysRegsLegacyPass()); |
| 448 | |
| 449 | // Preparations and optimizations related to register stackification. |
| 450 | if (getOptLevel() != CodeGenOptLevel::None) { |
| 451 | // Depend on LiveIntervals and perform some optimizations on it. |
| 452 | addPass(P: createWebAssemblyOptimizeLiveIntervalsLegacyPass()); |
| 453 | |
| 454 | // Prepare memory intrinsic calls for register stackifying. |
| 455 | addPass(P: createWebAssemblyMemIntrinsicResultsLegacyPass()); |
| 456 | } |
| 457 | |
| 458 | // Mark registers as representing wasm's value stack. This is a key |
| 459 | // code-compression technique in WebAssembly. We run this pass (and |
| 460 | // MemIntrinsicResults above) very late, so that it sees as much code as |
| 461 | // possible, including code emitted by PEI and expanded by late tail |
| 462 | // duplication. |
| 463 | addPass(P: createWebAssemblyRegStackifyLegacyPass(OptLevel: getOptLevel())); |
| 464 | |
| 465 | if (getOptLevel() != CodeGenOptLevel::None) { |
| 466 | // Run the register coloring pass to reduce the total number of registers. |
| 467 | // This runs after stackification so that it doesn't consider registers |
| 468 | // that become stackified. |
| 469 | addPass(P: createWebAssemblyRegColoringLegacyPass()); |
| 470 | } |
| 471 | |
| 472 | // Sort the blocks of the CFG into topological order, a prerequisite for |
| 473 | // BLOCK and LOOP markers. |
| 474 | addPass(P: createWebAssemblyCFGSortLegacyPass()); |
| 475 | |
| 476 | // Insert BLOCK and LOOP markers. |
| 477 | addPass(P: createWebAssemblyCFGStackifyLegacyPass()); |
| 478 | |
| 479 | // Insert explicit local.get and local.set operators. |
| 480 | if (!WasmDisableExplicitLocals) |
| 481 | addPass(P: createWebAssemblyExplicitLocalsLegacyPass()); |
| 482 | |
| 483 | // Lower br_unless into br_if. |
| 484 | addPass(P: createWebAssemblyLowerBrUnlessLegacyPass()); |
| 485 | |
| 486 | // Perform the very last peephole optimizations on the code. |
| 487 | if (getOptLevel() != CodeGenOptLevel::None) |
| 488 | addPass(P: createWebAssemblyPeepholeLegacyPass()); |
| 489 | |
| 490 | // Create a mapping from LLVM CodeGen virtual registers to wasm registers. |
| 491 | addPass(P: createWebAssemblyRegNumberingLegacyPass()); |
| 492 | |
| 493 | // Fix debug_values whose defs have been stackified. |
| 494 | if (!WasmDisableExplicitLocals) |
| 495 | addPass(P: createWebAssemblyDebugFixupLegacyPass()); |
| 496 | |
| 497 | // Collect information to prepare for MC lowering / asm printing. |
| 498 | addPass(P: createWebAssemblyMCLowerPreLegacyPass()); |
| 499 | } |
| 500 | |
| 501 | bool WebAssemblyPassConfig::addPreISel() { |
| 502 | TargetPassConfig::addPreISel(); |
| 503 | return false; |
| 504 | } |
| 505 | |
| 506 | bool WebAssemblyPassConfig::addIRTranslator() { |
| 507 | addPass(P: new IRTranslatorLegacy()); |
| 508 | return false; |
| 509 | } |
| 510 | |
| 511 | void WebAssemblyPassConfig::addPreLegalizeMachineIR() { |
| 512 | if (getOptLevel() != CodeGenOptLevel::None) { |
| 513 | addPass(P: createWebAssemblyPreLegalizerCombinerLegacyPass()); |
| 514 | } |
| 515 | } |
| 516 | bool WebAssemblyPassConfig::addLegalizeMachineIR() { |
| 517 | addPass(P: new LegalizerLegacy()); |
| 518 | return false; |
| 519 | } |
| 520 | |
| 521 | void WebAssemblyPassConfig::addPreRegBankSelect() { |
| 522 | if (getOptLevel() != CodeGenOptLevel::None) { |
| 523 | addPass(P: createWebAssemblyPostLegalizerCombinerLegacyPass()); |
| 524 | } |
| 525 | } |
| 526 | |
| 527 | bool WebAssemblyPassConfig::addRegBankSelect() { |
| 528 | addPass(P: new RegBankSelectLegacy()); |
| 529 | return false; |
| 530 | } |
| 531 | |
| 532 | bool WebAssemblyPassConfig::addGlobalInstructionSelect() { |
| 533 | addPass(P: new InstructionSelectLegacy(getOptLevel())); |
| 534 | |
| 535 | // We insert only if ISelDAG won't insert these at a later point. |
| 536 | if (isGlobalISelAbortEnabled()) { |
| 537 | addPass(P: createWebAssemblyArgumentMoveLegacyPass()); |
| 538 | addPass(P: createWebAssemblySetP2AlignOperandsLegacyPass()); |
| 539 | addPass(P: createWebAssemblyFixBrTableDefaultsLegacyPass()); |
| 540 | addPass(P: createWebAssemblyCleanCodeAfterTrapLegacyPass()); |
| 541 | } |
| 542 | |
| 543 | return false; |
| 544 | } |
| 545 | |
| 546 | yaml::MachineFunctionInfo * |
| 547 | WebAssemblyTargetMachine::createDefaultFuncInfoYAML() const { |
| 548 | return new yaml::WebAssemblyFunctionInfo(); |
| 549 | } |
| 550 | |
| 551 | yaml::MachineFunctionInfo *WebAssemblyTargetMachine::convertFuncInfoToYAML( |
| 552 | const MachineFunction &MF) const { |
| 553 | const auto *MFI = MF.getInfo<WebAssemblyFunctionInfo>(); |
| 554 | return new yaml::WebAssemblyFunctionInfo(MF, *MFI); |
| 555 | } |
| 556 | |
| 557 | bool WebAssemblyTargetMachine::parseMachineFunctionInfo( |
| 558 | const yaml::MachineFunctionInfo &MFI, PerFunctionMIParsingState &PFS, |
| 559 | SMDiagnostic &Error, SMRange &SourceRange) const { |
| 560 | const auto &YamlMFI = static_cast<const yaml::WebAssemblyFunctionInfo &>(MFI); |
| 561 | MachineFunction &MF = PFS.MF; |
| 562 | MF.getInfo<WebAssemblyFunctionInfo>()->initializeBaseYamlFields(MF, YamlMFI); |
| 563 | return false; |
| 564 | } |
| 565 | |