| //===-- VM.cpp - LLVM Just in Time Compiler -------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file was developed by the LLVM research group and is distributed under |
| // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This tool implements a just-in-time compiler for LLVM, allowing direct |
| // execution of LLVM bytecode in an efficient manner. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "VM.h" |
| #include "llvm/Function.h" |
| #include "llvm/ModuleProvider.h" |
| #include "llvm/CodeGen/MachineFunction.h" |
| #include "llvm/CodeGen/MachineCodeEmitter.h" |
| #include "llvm/Target/TargetMachine.h" |
| |
| namespace llvm { |
| |
| VM::~VM() { |
| delete MCE; |
| delete &TM; |
| } |
| |
| /// setupPassManager - Initialize the VM PassManager object with all of the |
| /// passes needed for the target to generate code. |
| /// |
| void VM::setupPassManager() { |
| // Compile LLVM Code down to machine code in the intermediate representation |
| if (TM.addPassesToJITCompile(PM)) { |
| std::cerr << "lli: target '" << TM.getName() |
| << "' doesn't support JIT compilation!\n"; |
| abort(); |
| } |
| |
| // Turn the machine code intermediate representation into bytes in memory that |
| // may be executed. |
| // |
| if (TM.addPassesToEmitMachineCode(PM, *MCE)) { |
| std::cerr << "lli: target '" << TM.getName() |
| << "' doesn't support machine code emission!\n"; |
| abort(); |
| } |
| } |
| |
| /// runJITOnFunction - Run the FunctionPassManager full of |
| /// just-in-time compilation passes on F, hopefully filling in |
| /// GlobalAddress[F] with the address of F's machine code. |
| /// |
| void VM::runJITOnFunction (Function *F) { |
| static bool isAlreadyCodeGenerating = false; |
| assert(!isAlreadyCodeGenerating && "ERROR: RECURSIVE COMPILATION DETECTED!"); |
| |
| // JIT the function |
| isAlreadyCodeGenerating = true; |
| PM.run(*F); |
| isAlreadyCodeGenerating = false; |
| } |
| |
| /// getPointerToFunction - This method is used to get the address of the |
| /// specified function, compiling it if neccesary. |
| /// |
| void *VM::getPointerToFunction(Function *F) { |
| void *&Addr = GlobalAddress[F]; // Check if function already code gen'd |
| if (Addr) return Addr; |
| |
| // Make sure we read in the function if it exists in this Module |
| MP->materializeFunction(F); |
| |
| if (F->isExternal()) |
| return Addr = getPointerToNamedFunction(F->getName()); |
| |
| runJITOnFunction (F); |
| assert(Addr && "Code generation didn't add function to GlobalAddress table!"); |
| return Addr; |
| } |
| |
| /// recompileAndRelinkFunction - This method is used to force a function |
| /// which has already been compiled, to be compiled again, possibly |
| /// after it has been modified. Then the entry to the old copy is overwritten |
| /// with a branch to the new copy. If there was no old copy, this acts |
| /// just like VM::getPointerToFunction(). |
| /// |
| void *VM::recompileAndRelinkFunction(Function *F) { |
| void *&Addr = GlobalAddress[F]; // Check if function already code gen'd |
| |
| // If it's not already compiled (this is kind of weird) there is no |
| // reason to patch it up. |
| if (!Addr) { return getPointerToFunction (F); } |
| |
| void *OldAddr = Addr; |
| Addr = 0; |
| MachineFunction::destruct (F); |
| runJITOnFunction (F); |
| assert(Addr && "Code generation didn't add function to GlobalAddress table!"); |
| TM.replaceMachineCodeForFunction (OldAddr, Addr); |
| return Addr; |
| } |
| |
| } // End llvm namespace |