1 //===-- TargetMachine.cpp - General Target Information ---------------------==//
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 describes the general parts of a Target machine.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/CodeGen/MachineFunction.h"
15 #include "llvm/CodeGen/MachineFrameInfo.h"
16 #include "llvm/MC/MCAsmInfo.h"
17 #include "llvm/Target/TargetMachine.h"
18 #include "llvm/Target/TargetOptions.h"
19 #include "llvm/Support/CommandLine.h"
20 using namespace llvm;
21 
22 //---------------------------------------------------------------------------
23 // Command-line options that tend to be useful on more than one back-end.
24 //
25 
26 namespace llvm {
27   bool StrongPHIElim;
28   bool HasDivModLibcall;
29   bool AsmVerbosityDefault(false);
30 }
31 
32 static cl::opt<bool>
33 DataSections("fdata-sections",
34   cl::desc("Emit data into separate sections"),
35   cl::init(false));
36 static cl::opt<bool>
37 FunctionSections("ffunction-sections",
38   cl::desc("Emit functions into separate sections"),
39   cl::init(false));
40 
41 //---------------------------------------------------------------------------
42 // TargetMachine Class
43 //
44 
45 TargetMachine::TargetMachine(const Target &T,
46                              StringRef TT, StringRef CPU, StringRef FS,
47                              const TargetOptions &Options)
48   : TheTarget(T), TargetTriple(TT), TargetCPU(CPU), TargetFS(FS),
49     CodeGenInfo(0), AsmInfo(0),
50     MCRelaxAll(false),
51     MCNoExecStack(false),
52     MCSaveTempLabels(false),
53     MCUseLoc(true),
54     MCUseCFI(true),
55     MCUseDwarfDirectory(false),
56     Options(Options) {
57 }
58 
59 TargetMachine::~TargetMachine() {
60   delete CodeGenInfo;
61   delete AsmInfo;
62 }
63 
64 /// getRelocationModel - Returns the code generation relocation model. The
65 /// choices are static, PIC, and dynamic-no-pic, and target default.
66 Reloc::Model TargetMachine::getRelocationModel() const {
67   if (!CodeGenInfo)
68     return Reloc::Default;
69   return CodeGenInfo->getRelocationModel();
70 }
71 
72 /// getCodeModel - Returns the code model. The choices are small, kernel,
73 /// medium, large, and target default.
74 CodeModel::Model TargetMachine::getCodeModel() const {
75   if (!CodeGenInfo)
76     return CodeModel::Default;
77   return CodeGenInfo->getCodeModel();
78 }
79 
80 /// getOptLevel - Returns the optimization level: None, Less,
81 /// Default, or Aggressive.
82 CodeGenOpt::Level TargetMachine::getOptLevel() const {
83   if (!CodeGenInfo)
84     return CodeGenOpt::Default;
85   return CodeGenInfo->getOptLevel();
86 }
87 
88 bool TargetMachine::getAsmVerbosityDefault() {
89   return AsmVerbosityDefault;
90 }
91 
92 void TargetMachine::setAsmVerbosityDefault(bool V) {
93   AsmVerbosityDefault = V;
94 }
95 
96 bool TargetMachine::getFunctionSections() {
97   return FunctionSections;
98 }
99 
100 bool TargetMachine::getDataSections() {
101   return DataSections;
102 }
103 
104 void TargetMachine::setFunctionSections(bool V) {
105   FunctionSections = V;
106 }
107 
108 void TargetMachine::setDataSections(bool V) {
109   DataSections = V;
110 }
111 
112 /// DisableFramePointerElim - This returns true if frame pointer elimination
113 /// optimization should be disabled for the given machine function.
114 bool TargetOptions::DisableFramePointerElim(const MachineFunction &MF) const {
115   // Check to see if we should eliminate non-leaf frame pointers and then
116   // check to see if we should eliminate all frame pointers.
117   if (NoFramePointerElimNonLeaf && !NoFramePointerElim) {
118     const MachineFrameInfo *MFI = MF.getFrameInfo();
119     return MFI->hasCalls();
120   }
121 
122   return NoFramePointerElim;
123 }
124 
125 /// LessPreciseFPMAD - This flag return true when -enable-fp-mad option
126 /// is specified on the command line.  When this flag is off(default), the
127 /// code generator is not allowed to generate mad (multiply add) if the
128 /// result is "less precise" than doing those operations individually.
129 bool TargetOptions::LessPreciseFPMAD() const {
130   return UnsafeFPMath || LessPreciseFPMADOption;
131 }
132 
133 /// HonorSignDependentRoundingFPMath - Return true if the codegen must assume
134 /// that the rounding mode of the FPU can change from its default.
135 bool TargetOptions::HonorSignDependentRoundingFPMath() const {
136   return !UnsafeFPMath && HonorSignDependentRoundingFPMathOption;
137 }
138 
139 /// getTrapFunctionName - If this returns a non-empty string, this means isel
140 /// should lower Intrinsic::trap to a call to the specified function name
141 /// instead of an ISD::TRAP node.
142 StringRef TargetOptions::getTrapFunctionName() const {
143   return TrapFuncName;
144 }
145