1 //===-- MipsTargetMachine.cpp - Define TargetMachine for Mips -------------===//
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 // Implements the info about Mips target spec.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "Mips.h"
15 #include "MipsMCAsmInfo.h"
16 #include "MipsTargetMachine.h"
17 #include "llvm/PassManager.h"
18 #include "llvm/Target/TargetRegistry.h"
19 using namespace llvm;
20 
21 extern "C" void LLVMInitializeMipsTarget() {
22   // Register the target.
23   RegisterTargetMachine<MipsTargetMachine> X(TheMipsTarget);
24   RegisterTargetMachine<MipselTargetMachine> Y(TheMipselTarget);
25   RegisterAsmInfo<MipsMCAsmInfo> A(TheMipsTarget);
26   RegisterAsmInfo<MipsMCAsmInfo> B(TheMipselTarget);
27 }
28 
29 // DataLayout --> Big-endian, 32-bit pointer/ABI/alignment
30 // The stack is always 8 byte aligned
31 // On function prologue, the stack is created by decrementing
32 // its pointer. Once decremented, all references are done with positive
33 // offset from the stack/frame pointer, using StackGrowsUp enables
34 // an easier handling.
35 // Using CodeModel::Large enables different CALL behavior.
36 MipsTargetMachine::
37 MipsTargetMachine(const Target &T, const std::string &TT, const std::string &FS,
38                   bool isLittle=false):
39   LLVMTargetMachine(T, TT),
40   Subtarget(TT, FS, isLittle),
41   DataLayout(isLittle ? std::string("e-p:32:32:32-i8:8:32-i16:16:32-n32") :
42                         std::string("E-p:32:32:32-i8:8:32-i16:16:32-n32")),
43   InstrInfo(*this),
44   FrameInfo(TargetFrameInfo::StackGrowsUp, 8, 0),
45   TLInfo(*this) {
46   // Abicall enables PIC by default
47   if (getRelocationModel() == Reloc::Default) {
48     if (Subtarget.isABI_O32())
49       setRelocationModel(Reloc::PIC_);
50     else
51       setRelocationModel(Reloc::Static);
52   }
53 
54   // TODO: create an option to enable long calls, like -mlong-calls,
55   // that would be our CodeModel::Large. It must not work with Abicall.
56   if (getCodeModel() == CodeModel::Default)
57     setCodeModel(CodeModel::Small);
58 }
59 
60 MipselTargetMachine::
61 MipselTargetMachine(const Target &T, const std::string &TT,
62                     const std::string &FS) :
63   MipsTargetMachine(T, TT, FS, true) {}
64 
65 // Install an instruction selector pass using
66 // the ISelDag to gen Mips code.
67 bool MipsTargetMachine::
68 addInstSelector(PassManagerBase &PM, CodeGenOpt::Level OptLevel)
69 {
70   PM.add(createMipsISelDag(*this));
71   return false;
72 }
73 
74 // Implemented by targets that want to run passes immediately before
75 // machine code is emitted. return true if -print-machineinstrs should
76 // print out the code after the passes.
77 bool MipsTargetMachine::
78 addPreEmitPass(PassManagerBase &PM, CodeGenOpt::Level OptLevel)
79 {
80   PM.add(createMipsDelaySlotFillerPass(*this));
81   return true;
82 }
83