1 //===-- Passes.cpp - Target independent code generation passes ------------===// 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 defines interfaces to access the target independent code 11 // generation passes provided by the LLVM backend. 12 // 13 //===---------------------------------------------------------------------===// 14 15 #include "llvm/CodeGen/RegAllocRegistry.h" 16 #include "llvm/CodeGen/Passes.h" 17 18 using namespace llvm; 19 20 //===---------------------------------------------------------------------===// 21 /// 22 /// RegisterRegAlloc class - Track the registration of register allocators. 23 /// 24 //===---------------------------------------------------------------------===// 25 MachinePassRegistry RegisterRegAlloc::Registry; 26 27 static FunctionPass *createDefaultRegisterAllocator() { return 0; } 28 static RegisterRegAlloc 29 defaultRegAlloc("default", 30 "pick register allocator based on -O option", 31 createDefaultRegisterAllocator); 32 33 //===---------------------------------------------------------------------===// 34 /// 35 /// RegAlloc command line options. 36 /// 37 //===---------------------------------------------------------------------===// 38 static cl::opt<RegisterRegAlloc::FunctionPassCtor, false, 39 RegisterPassParser<RegisterRegAlloc> > 40 RegAlloc("regalloc", 41 cl::init(&createDefaultRegisterAllocator), 42 cl::desc("Register allocator to use")); 43 44 45 //===---------------------------------------------------------------------===// 46 /// 47 /// createRegisterAllocator - choose the appropriate register allocator. 48 /// 49 //===---------------------------------------------------------------------===// 50 FunctionPass *llvm::createRegisterAllocator(CodeGenOpt::Level OptLevel) { 51 RegisterRegAlloc::FunctionPassCtor Ctor = RegisterRegAlloc::getDefault(); 52 53 if (!Ctor) { 54 Ctor = RegAlloc; 55 RegisterRegAlloc::setDefault(RegAlloc); 56 } 57 58 // This forces linking of the linear scan register allocator, 59 // so -regalloc=linearscan still works in clang. 60 if (Ctor == createLinearScanRegisterAllocator) 61 return createLinearScanRegisterAllocator(); 62 63 if (Ctor != createDefaultRegisterAllocator) 64 return Ctor(); 65 66 // When the 'default' allocator is requested, pick one based on OptLevel. 67 switch (OptLevel) { 68 case CodeGenOpt::None: 69 return createFastRegisterAllocator(); 70 default: 71 return createGreedyRegisterAllocator(); 72 } 73 } 74
