LLVMTargetMachine.cpp revision 8f0d99e463a2dcb5a40d14f0481a0e322bcf79e4 
1//===-- LLVMTargetMachine.cpp - Implement the LLVMTargetMachine class -----===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the LLVMTargetMachine class.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Target/TargetMachine.h"
15#include "llvm/PassManager.h"
16#include "llvm/Pass.h"
17#include "llvm/Assembly/PrintModulePass.h"
18#include "llvm/Analysis/LoopPass.h"
19#include "llvm/CodeGen/Passes.h"
20#include "llvm/CodeGen/GCStrategy.h"
21#include "llvm/Target/TargetOptions.h"
22#include "llvm/Target/TargetAsmInfo.h"
23#include "llvm/Transforms/Scalar.h"
24#include "llvm/Support/CommandLine.h"
25#include "llvm/Support/raw_ostream.h"
26using namespace llvm;
27
28namespace llvm {
29  bool EnableFastISel;
30}
31
32static cl::opt<bool> PrintLSR("print-lsr-output", cl::Hidden,
33    cl::desc("Print LLVM IR produced by the loop-reduce pass"));
34static cl::opt<bool> PrintISelInput("print-isel-input", cl::Hidden,
35    cl::desc("Print LLVM IR input to isel pass"));
36static cl::opt<bool> PrintEmittedAsm("print-emitted-asm", cl::Hidden,
37    cl::desc("Dump emitter generated instructions as assembly"));
38static cl::opt<bool> PrintGCInfo("print-gc", cl::Hidden,
39    cl::desc("Dump garbage collector data"));
40
41// When this works it will be on by default.
42static cl::opt<bool>
43DisablePostRAScheduler("disable-post-RA-scheduler",
44                       cl::desc("Disable scheduling after register allocation"),
45                       cl::init(true));
46
47// Enable or disable FastISel. Both options are needed, because
48// FastISel is enabled by default with -fast, and we wish to be
49// able to enable or disable fast-isel independently from -fast.
50static cl::opt<cl::boolOrDefault>
51EnableFastISelOption("fast-isel", cl::Hidden,
52  cl::desc("Enable the experimental \"fast\" instruction selector"));
53
54FileModel::Model
55LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
56                                       raw_ostream &Out,
57                                       CodeGenFileType FileType,
58                                       bool Fast) {
59  // Add common CodeGen passes.
60  if (addCommonCodeGenPasses(PM, Fast))
61    return FileModel::Error;
62
63  // Fold redundant debug labels.
64  PM.add(createDebugLabelFoldingPass());
65
66  if (PrintMachineCode)
67    PM.add(createMachineFunctionPrinterPass(cerr));
68
69  if (addPreEmitPass(PM, Fast) && PrintMachineCode)
70    PM.add(createMachineFunctionPrinterPass(cerr));
71
72  if (!Fast)
73    PM.add(createLoopAlignerPass());
74
75  switch (FileType) {
76  default:
77    break;
78  case TargetMachine::AssemblyFile:
79    if (addAssemblyEmitter(PM, Fast, Out))
80      return FileModel::Error;
81    return FileModel::AsmFile;
82  case TargetMachine::ObjectFile:
83    if (getMachOWriterInfo())
84      return FileModel::MachOFile;
85    else if (getELFWriterInfo())
86      return FileModel::ElfFile;
87  }
88
89  return FileModel::Error;
90}
91
92/// addPassesToEmitFileFinish - If the passes to emit the specified file had to
93/// be split up (e.g., to add an object writer pass), this method can be used to
94/// finish up adding passes to emit the file, if necessary.
95bool LLVMTargetMachine::addPassesToEmitFileFinish(PassManagerBase &PM,
96                                                  MachineCodeEmitter *MCE,
97                                                  bool Fast) {
98  if (MCE)
99    addSimpleCodeEmitter(PM, Fast, PrintEmittedAsm, *MCE);
100
101  PM.add(createGCInfoDeleter());
102
103  // Delete machine code for this function
104  PM.add(createMachineCodeDeleter());
105
106  return false; // success!
107}
108
109/// addPassesToEmitMachineCode - Add passes to the specified pass manager to
110/// get machine code emitted.  This uses a MachineCodeEmitter object to handle
111/// actually outputting the machine code and resolving things like the address
112/// of functions.  This method should returns true if machine code emission is
113/// not supported.
114///
115bool LLVMTargetMachine::addPassesToEmitMachineCode(PassManagerBase &PM,
116                                                   MachineCodeEmitter &MCE,
117                                                   bool Fast) {
118  // Add common CodeGen passes.
119  if (addCommonCodeGenPasses(PM, Fast))
120    return true;
121
122  if (addPreEmitPass(PM, Fast) && PrintMachineCode)
123    PM.add(createMachineFunctionPrinterPass(cerr));
124
125  addCodeEmitter(PM, Fast, PrintEmittedAsm, MCE);
126
127  PM.add(createGCInfoDeleter());
128
129  // Delete machine code for this function
130  PM.add(createMachineCodeDeleter());
131
132  return false; // success!
133}
134
135/// addCommonCodeGenPasses - Add standard LLVM codegen passes used for
136/// both emitting to assembly files or machine code output.
137///
138bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM, bool Fast) {
139  // Standard LLVM-Level Passes.
140
141  // Run loop strength reduction before anything else.
142  if (!Fast) {
143    PM.add(createLoopStrengthReducePass(getTargetLowering()));
144    if (PrintLSR)
145      PM.add(createPrintFunctionPass("\n\n*** Code after LSR ***\n", &errs()));
146  }
147
148  PM.add(createGCLoweringPass());
149
150  if (!getTargetAsmInfo()->doesSupportExceptionHandling())
151    PM.add(createLowerInvokePass(getTargetLowering()));
152
153  // Make sure that no unreachable blocks are instruction selected.
154  PM.add(createUnreachableBlockEliminationPass());
155
156  if (!Fast)
157    PM.add(createCodeGenPreparePass(getTargetLowering()));
158
159  PM.add(createStackProtectorPass(getTargetLowering()));
160
161  if (PrintISelInput)
162    PM.add(createPrintFunctionPass("\n\n"
163                                   "*** Final LLVM Code input to ISel ***\n",
164                                   &errs()));
165
166  // Standard Lower-Level Passes.
167
168  // Enable FastISel with -fast, but allow that to be overridden.
169  if (EnableFastISelOption == cl::BOU_TRUE ||
170      (Fast && EnableFastISelOption != cl::BOU_FALSE))
171    EnableFastISel = true;
172
173  // Ask the target for an isel.
174  if (addInstSelector(PM, Fast))
175    return true;
176
177  // Print the instruction selected machine code...
178  if (PrintMachineCode)
179    PM.add(createMachineFunctionPrinterPass(cerr));
180
181  if (!Fast) {
182    PM.add(createMachineLICMPass());
183    PM.add(createMachineSinkingPass());
184  }
185
186  // Run pre-ra passes.
187  if (addPreRegAlloc(PM, Fast) && PrintMachineCode)
188    PM.add(createMachineFunctionPrinterPass(cerr));
189
190  // Perform register allocation.
191  PM.add(createRegisterAllocator());
192
193  // Perform stack slot coloring.
194  if (!Fast)
195    PM.add(createStackSlotColoringPass());
196
197  if (PrintMachineCode)  // Print the register-allocated code
198    PM.add(createMachineFunctionPrinterPass(cerr));
199
200  // Run post-ra passes.
201  if (addPostRegAlloc(PM, Fast) && PrintMachineCode)
202    PM.add(createMachineFunctionPrinterPass(cerr));
203
204  if (PrintMachineCode)
205    PM.add(createMachineFunctionPrinterPass(cerr));
206
207  PM.add(createLowerSubregsPass());
208
209  if (PrintMachineCode)  // Print the subreg lowered code
210    PM.add(createMachineFunctionPrinterPass(cerr));
211
212  // Insert prolog/epilog code.  Eliminate abstract frame index references...
213  PM.add(createPrologEpilogCodeInserter());
214
215  if (PrintMachineCode)
216    PM.add(createMachineFunctionPrinterPass(cerr));
217
218  // Second pass scheduler.
219  if (!Fast && !DisablePostRAScheduler) {
220    PM.add(createPostRAScheduler());
221
222    if (PrintMachineCode)
223      PM.add(createMachineFunctionPrinterPass(cerr));
224  }
225
226  // Branch folding must be run after regalloc and prolog/epilog insertion.
227  if (!Fast)
228    PM.add(createBranchFoldingPass(getEnableTailMergeDefault()));
229
230  if (PrintMachineCode)
231    PM.add(createMachineFunctionPrinterPass(cerr));
232
233  PM.add(createGCMachineCodeAnalysisPass());
234
235  if (PrintMachineCode)
236    PM.add(createMachineFunctionPrinterPass(cerr));
237
238  if (PrintGCInfo)
239    PM.add(createGCInfoPrinter(*cerr));
240
241  return false;
242}
243