1 //===-- Passes.cpp - Target independent code generation passes ------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines interfaces to access the target independent code
11 // generation passes provided by the LLVM backend.
13 //===---------------------------------------------------------------------===//
15 #include "llvm/Analysis/Passes.h"
16 #include "llvm/Analysis/Verifier.h"
17 #include "llvm/Transforms/Scalar.h"
18 #include "llvm/PassManager.h"
19 #include "llvm/CodeGen/GCStrategy.h"
20 #include "llvm/CodeGen/MachineFunctionPass.h"
21 #include "llvm/CodeGen/Passes.h"
22 #include "llvm/CodeGen/RegAllocRegistry.h"
23 #include "llvm/Target/TargetLowering.h"
24 #include "llvm/Target/TargetOptions.h"
25 #include "llvm/Assembly/PrintModulePass.h"
26 #include "llvm/Support/CommandLine.h"
27 #include "llvm/Support/Debug.h"
28 #include "llvm/Support/ErrorHandling.h"
32 static cl::opt<bool> DisablePostRA("disable-post-ra", cl::Hidden,
33 cl::desc("Disable Post Regalloc"));
34 static cl::opt<bool> DisableBranchFold("disable-branch-fold", cl::Hidden,
35 cl::desc("Disable branch folding"));
36 static cl::opt<bool> DisableTailDuplicate("disable-tail-duplicate", cl::Hidden,
37 cl::desc("Disable tail duplication"));
38 static cl::opt<bool> DisableEarlyTailDup("disable-early-taildup", cl::Hidden,
39 cl::desc("Disable pre-register allocation tail duplication"));
40 static cl::opt<bool> EnableBlockPlacement("enable-block-placement",
41 cl::Hidden, cl::desc("Enable probability-driven block placement"));
42 static cl::opt<bool> EnableBlockPlacementStats("enable-block-placement-stats",
43 cl::Hidden, cl::desc("Collect probability-driven block placement stats"));
44 static cl::opt<bool> DisableCodePlace("disable-code-place", cl::Hidden,
45 cl::desc("Disable code placement"));
46 static cl::opt<bool> DisableSSC("disable-ssc", cl::Hidden,
47 cl::desc("Disable Stack Slot Coloring"));
48 static cl::opt<bool> DisableMachineDCE("disable-machine-dce", cl::Hidden,
49 cl::desc("Disable Machine Dead Code Elimination"));
50 static cl::opt<bool> DisableMachineLICM("disable-machine-licm", cl::Hidden,
51 cl::desc("Disable Machine LICM"));
52 static cl::opt<bool> DisableMachineCSE("disable-machine-cse", cl::Hidden,
53 cl::desc("Disable Machine Common Subexpression Elimination"));
54 static cl::opt<bool> DisablePostRAMachineLICM("disable-postra-machine-licm",
56 cl::desc("Disable Machine LICM"));
57 static cl::opt<bool> DisableMachineSink("disable-machine-sink", cl::Hidden,
58 cl::desc("Disable Machine Sinking"));
59 static cl::opt<bool> DisableLSR("disable-lsr", cl::Hidden,
60 cl::desc("Disable Loop Strength Reduction Pass"));
61 static cl::opt<bool> DisableCGP("disable-cgp", cl::Hidden,
62 cl::desc("Disable Codegen Prepare"));
63 static cl::opt<bool> DisableCopyProp("disable-copyprop", cl::Hidden,
64 cl::desc("Disable Copy Propagation pass"));
65 static cl::opt<bool> PrintLSR("print-lsr-output", cl::Hidden,
66 cl::desc("Print LLVM IR produced by the loop-reduce pass"));
67 static cl::opt<bool> PrintISelInput("print-isel-input", cl::Hidden,
68 cl::desc("Print LLVM IR input to isel pass"));
69 static cl::opt<bool> PrintGCInfo("print-gc", cl::Hidden,
70 cl::desc("Dump garbage collector data"));
71 static cl::opt<bool> VerifyMachineCode("verify-machineinstrs", cl::Hidden,
72 cl::desc("Verify generated machine code"),
73 cl::init(getenv("LLVM_VERIFY_MACHINEINSTRS")!=NULL));
75 //===---------------------------------------------------------------------===//
77 //===---------------------------------------------------------------------===//
79 INITIALIZE_PASS(TargetPassConfig, "targetpassconfig",
80 "Target Pass Configuration", false, false)
81 char TargetPassConfig::ID = 0;
83 // Out of line virtual method.
84 TargetPassConfig::~TargetPassConfig() {}
86 TargetPassConfig::TargetPassConfig(TargetMachine *tm, PassManagerBase &pm)
87 : ImmutablePass(ID), TM(tm), PM(pm), Initialized(false),
89 EnableTailMerge(true) {
91 // Register all target independent codegen passes to activate their PassIDs,
92 // including this pass itself.
93 initializeCodeGen(*PassRegistry::getPassRegistry());
96 /// createPassConfig - Create a pass configuration object to be used by
97 /// addPassToEmitX methods for generating a pipeline of CodeGen passes.
99 /// Targets may override this to extend TargetPassConfig.
100 TargetPassConfig *LLVMTargetMachine::createPassConfig(PassManagerBase &PM) {
101 return new TargetPassConfig(this, PM);
104 TargetPassConfig::TargetPassConfig()
105 : ImmutablePass(ID), PM(*(PassManagerBase*)0) {
106 llvm_unreachable("TargetPassConfig should not be constructed on-the-fly");
109 // Helper to verify the analysis is really immutable.
110 void TargetPassConfig::setOpt(bool &Opt, bool Val) {
111 assert(!Initialized && "PassConfig is immutable");
115 void TargetPassConfig::addPass(char &ID) {
116 // FIXME: check user overrides
117 Pass *P = Pass::createPass(ID);
119 llvm_unreachable("Pass ID not registered");
123 void TargetPassConfig::printNoVerify(const char *Banner) const {
124 if (TM->shouldPrintMachineCode())
125 PM.add(createMachineFunctionPrinterPass(dbgs(), Banner));
128 void TargetPassConfig::printAndVerify(const char *Banner) const {
129 if (TM->shouldPrintMachineCode())
130 PM.add(createMachineFunctionPrinterPass(dbgs(), Banner));
132 if (VerifyMachineCode)
133 PM.add(createMachineVerifierPass(Banner));
136 /// Add common target configurable passes that perform LLVM IR to IR transforms
137 /// following machine independent optimization.
138 void TargetPassConfig::addIRPasses() {
139 // Basic AliasAnalysis support.
140 // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
141 // BasicAliasAnalysis wins if they disagree. This is intended to help
142 // support "obvious" type-punning idioms.
143 PM.add(createTypeBasedAliasAnalysisPass());
144 PM.add(createBasicAliasAnalysisPass());
146 // Before running any passes, run the verifier to determine if the input
147 // coming from the front-end and/or optimizer is valid.
149 PM.add(createVerifierPass());
151 // Run loop strength reduction before anything else.
152 if (getOptLevel() != CodeGenOpt::None && !DisableLSR) {
153 PM.add(createLoopStrengthReducePass(getTargetLowering()));
155 PM.add(createPrintFunctionPass("\n\n*** Code after LSR ***\n", &dbgs()));
158 PM.add(createGCLoweringPass());
160 // Make sure that no unreachable blocks are instruction selected.
161 PM.add(createUnreachableBlockEliminationPass());
164 /// Add common passes that perform LLVM IR to IR transforms in preparation for
165 /// instruction selection.
166 void TargetPassConfig::addISelPrepare() {
167 if (getOptLevel() != CodeGenOpt::None && !DisableCGP)
168 PM.add(createCodeGenPreparePass(getTargetLowering()));
170 PM.add(createStackProtectorPass(getTargetLowering()));
175 PM.add(createPrintFunctionPass("\n\n"
176 "*** Final LLVM Code input to ISel ***\n",
179 // All passes which modify the LLVM IR are now complete; run the verifier
180 // to ensure that the IR is valid.
182 PM.add(createVerifierPass());
185 void TargetPassConfig::addMachinePasses() {
186 // Print the instruction selected machine code...
187 printAndVerify("After Instruction Selection");
189 // Expand pseudo-instructions emitted by ISel.
190 PM.add(createExpandISelPseudosPass());
192 // Pre-ra tail duplication.
193 if (getOptLevel() != CodeGenOpt::None && !DisableEarlyTailDup) {
194 PM.add(createTailDuplicatePass());
195 printAndVerify("After Pre-RegAlloc TailDuplicate");
198 // Optimize PHIs before DCE: removing dead PHI cycles may make more
199 // instructions dead.
200 if (getOptLevel() != CodeGenOpt::None)
201 PM.add(createOptimizePHIsPass());
203 // If the target requests it, assign local variables to stack slots relative
204 // to one another and simplify frame index references where possible.
205 PM.add(createLocalStackSlotAllocationPass());
207 if (getOptLevel() != CodeGenOpt::None) {
208 // With optimization, dead code should already be eliminated. However
209 // there is one known exception: lowered code for arguments that are only
210 // used by tail calls, where the tail calls reuse the incoming stack
211 // arguments directly (see t11 in test/CodeGen/X86/sibcall.ll).
212 if (!DisableMachineDCE)
213 PM.add(createDeadMachineInstructionElimPass());
214 printAndVerify("After codegen DCE pass");
216 if (!DisableMachineLICM)
217 PM.add(createMachineLICMPass());
218 if (!DisableMachineCSE)
219 PM.add(createMachineCSEPass());
220 if (!DisableMachineSink)
221 PM.add(createMachineSinkingPass());
222 printAndVerify("After Machine LICM, CSE and Sinking passes");
224 PM.add(createPeepholeOptimizerPass());
225 printAndVerify("After codegen peephole optimization pass");
228 // Run pre-ra passes.
229 if (addPreRegAlloc())
230 printAndVerify("After PreRegAlloc passes");
232 // Perform register allocation.
233 PM.add(createRegisterAllocator(getOptLevel()));
234 printAndVerify("After Register Allocation");
236 // Perform stack slot coloring and post-ra machine LICM.
237 if (getOptLevel() != CodeGenOpt::None) {
238 // FIXME: Re-enable coloring with register when it's capable of adding
241 PM.add(createStackSlotColoringPass(false));
243 // Run post-ra machine LICM to hoist reloads / remats.
244 if (!DisablePostRAMachineLICM)
245 PM.add(createMachineLICMPass(false));
247 printAndVerify("After StackSlotColoring and postra Machine LICM");
250 // Run post-ra passes.
251 if (addPostRegAlloc())
252 printAndVerify("After PostRegAlloc passes");
254 // Insert prolog/epilog code. Eliminate abstract frame index references...
255 PM.add(createPrologEpilogCodeInserter());
256 printAndVerify("After PrologEpilogCodeInserter");
258 // Branch folding must be run after regalloc and prolog/epilog insertion.
259 if (getOptLevel() != CodeGenOpt::None && !DisableBranchFold) {
260 PM.add(createBranchFoldingPass(getEnableTailMergeDefault()));
261 printNoVerify("After BranchFolding");
265 if (getOptLevel() != CodeGenOpt::None && !DisableTailDuplicate) {
266 PM.add(createTailDuplicatePass());
267 printNoVerify("After TailDuplicate");
271 if (getOptLevel() != CodeGenOpt::None && !DisableCopyProp) {
272 PM.add(createMachineCopyPropagationPass());
273 printNoVerify("After copy propagation pass");
276 // Expand pseudo instructions before second scheduling pass.
277 PM.add(createExpandPostRAPseudosPass());
278 printNoVerify("After ExpandPostRAPseudos");
280 // Run pre-sched2 passes.
282 printNoVerify("After PreSched2 passes");
284 // Second pass scheduler.
285 if (getOptLevel() != CodeGenOpt::None && !DisablePostRA) {
286 PM.add(createPostRAScheduler(getOptLevel()));
287 printNoVerify("After PostRAScheduler");
290 PM.add(createGCMachineCodeAnalysisPass());
293 PM.add(createGCInfoPrinter(dbgs()));
295 if (getOptLevel() != CodeGenOpt::None && !DisableCodePlace) {
296 if (EnableBlockPlacement) {
297 // MachineBlockPlacement is an experimental pass which is disabled by
298 // default currently. Eventually it should subsume CodePlacementOpt, so
299 // when enabled, the other is disabled.
300 PM.add(createMachineBlockPlacementPass());
301 printNoVerify("After MachineBlockPlacement");
303 PM.add(createCodePlacementOptPass());
304 printNoVerify("After CodePlacementOpt");
307 // Run a separate pass to collect block placement statistics.
308 if (EnableBlockPlacementStats) {
309 PM.add(createMachineBlockPlacementStatsPass());
310 printNoVerify("After MachineBlockPlacementStats");
314 if (addPreEmitPass())
315 printNoVerify("After PreEmit passes");
318 //===---------------------------------------------------------------------===//
320 /// RegisterRegAlloc class - Track the registration of register allocators.
322 //===---------------------------------------------------------------------===//
323 MachinePassRegistry RegisterRegAlloc::Registry;
325 static FunctionPass *createDefaultRegisterAllocator() { return 0; }
326 static RegisterRegAlloc
327 defaultRegAlloc("default",
328 "pick register allocator based on -O option",
329 createDefaultRegisterAllocator);
331 //===---------------------------------------------------------------------===//
333 /// RegAlloc command line options.
335 //===---------------------------------------------------------------------===//
336 static cl::opt<RegisterRegAlloc::FunctionPassCtor, false,
337 RegisterPassParser<RegisterRegAlloc> >
339 cl::init(&createDefaultRegisterAllocator),
340 cl::desc("Register allocator to use"));
343 //===---------------------------------------------------------------------===//
345 /// createRegisterAllocator - choose the appropriate register allocator.
347 //===---------------------------------------------------------------------===//
348 FunctionPass *llvm::createRegisterAllocator(CodeGenOpt::Level OptLevel) {
349 RegisterRegAlloc::FunctionPassCtor Ctor = RegisterRegAlloc::getDefault();
353 RegisterRegAlloc::setDefault(RegAlloc);
356 if (Ctor != createDefaultRegisterAllocator)
359 // When the 'default' allocator is requested, pick one based on OptLevel.
361 case CodeGenOpt::None:
362 return createFastRegisterAllocator();
364 return createGreedyRegisterAllocator();