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https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11041 91177308-0d34-0410-b5e6-96231b3b80d8
201 lines
6.8 KiB
C++
201 lines
6.8 KiB
C++
//===-- JIT.cpp - LLVM Just in Time Compiler ------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This tool implements a just-in-time compiler for LLVM, allowing direct
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// execution of LLVM bytecode in an efficient manner.
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//
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//===----------------------------------------------------------------------===//
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#include "JIT.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Function.h"
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#include "llvm/GlobalVariable.h"
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#include "llvm/ModuleProvider.h"
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#include "llvm/CodeGen/MachineCodeEmitter.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/ExecutionEngine/GenericValue.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Target/TargetJITInfo.h"
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#include "Support/DynamicLinker.h"
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using namespace llvm;
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JIT::JIT(ModuleProvider *MP, TargetMachine &tm, TargetJITInfo &tji)
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: ExecutionEngine(MP), TM(tm), TJI(tji), PM(MP) {
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setTargetData(TM.getTargetData());
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// Initialize MCE
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MCE = createEmitter(*this);
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// Compile LLVM Code down to machine code in the intermediate representation
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TJI.addPassesToJITCompile(PM);
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// Turn the machine code intermediate representation into bytes in memory that
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// may be executed.
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if (TM.addPassesToEmitMachineCode(PM, *MCE)) {
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std::cerr << "lli: target '" << TM.getName()
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<< "' doesn't support machine code emission!\n";
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abort();
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}
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}
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JIT::~JIT() {
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delete MCE;
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delete &TM;
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}
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/// run - Start execution with the specified function and arguments.
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///
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GenericValue JIT::runFunction(Function *F,
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const std::vector<GenericValue> &ArgValues) {
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assert (F && "Function *F was null at entry to run()");
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GenericValue rv;
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if (ArgValues.size() == 3) {
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int (*PF)(int, char **, const char **) =
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(int(*)(int, char **, const char **))getPointerToFunction(F);
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assert(PF && "Pointer to fn's code was null after getPointerToFunction");
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// Call the function.
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int ExitCode = PF(ArgValues[0].IntVal, (char **) GVTOP (ArgValues[1]),
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(const char **) GVTOP (ArgValues[2]));
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rv.IntVal = ExitCode;
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} else {
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// FIXME: This code should handle a couple of common cases efficiently, but
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// it should also implement the general case by code-gening a new anonymous
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// nullary function to call.
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assert(ArgValues.size() == 1);
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void (*PF)(int) = (void(*)(int))getPointerToFunction(F);
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assert(PF && "Pointer to fn's code was null after getPointerToFunction");
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PF(ArgValues[0].IntVal);
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}
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return rv;
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}
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/// runJITOnFunction - Run the FunctionPassManager full of
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/// just-in-time compilation passes on F, hopefully filling in
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/// GlobalAddress[F] with the address of F's machine code.
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///
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void JIT::runJITOnFunction(Function *F) {
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static bool isAlreadyCodeGenerating = false;
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assert(!isAlreadyCodeGenerating && "Error: Recursive compilation detected!");
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// JIT the function
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isAlreadyCodeGenerating = true;
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PM.run(*F);
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isAlreadyCodeGenerating = false;
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// If the function referred to a global variable that had not yet been
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// emitted, it allocates memory for the global, but doesn't emit it yet. Emit
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// all of these globals now.
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while (!PendingGlobals.empty()) {
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const GlobalVariable *GV = PendingGlobals.back();
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PendingGlobals.pop_back();
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EmitGlobalVariable(GV);
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}
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}
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/// getPointerToFunction - This method is used to get the address of the
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/// specified function, compiling it if neccesary.
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///
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void *JIT::getPointerToFunction(Function *F) {
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if (void *Addr = getPointerToGlobalIfAvailable(F))
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return Addr; // Check if function already code gen'd
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// Make sure we read in the function if it exists in this Module
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try {
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MP->materializeFunction(F);
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} catch (...) {
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std::cerr << "Error parsing bytecode file!\n";
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abort();
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}
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if (F->isExternal()) {
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void *Addr = getPointerToNamedFunction(F->getName());
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addGlobalMapping(F, Addr);
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return Addr;
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}
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runJITOnFunction(F);
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void *Addr = getPointerToGlobalIfAvailable(F);
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assert(Addr && "Code generation didn't add function to GlobalAddress table!");
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return Addr;
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}
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// getPointerToFunctionOrStub - If the specified function has been
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// code-gen'd, return a pointer to the function. If not, compile it, or use
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// a stub to implement lazy compilation if available.
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//
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void *JIT::getPointerToFunctionOrStub(Function *F) {
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// If we have already code generated the function, just return the address.
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if (void *Addr = getPointerToGlobalIfAvailable(F))
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return Addr;
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// If the target supports "stubs" for functions, get a stub now.
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if (void *Ptr = TJI.getJITStubForFunction(F, *MCE))
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return Ptr;
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// Otherwise, if the target doesn't support it, just codegen the function.
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return getPointerToFunction(F);
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}
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/// getOrEmitGlobalVariable - Return the address of the specified global
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/// variable, possibly emitting it to memory if needed. This is used by the
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/// Emitter.
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void *JIT::getOrEmitGlobalVariable(const GlobalVariable *GV) {
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void *Ptr = getPointerToGlobalIfAvailable(GV);
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if (Ptr) return Ptr;
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// If the global is external, just remember the address.
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if (GV->isExternal()) {
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Ptr = GetAddressOfSymbol(GV->getName().c_str());
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if (Ptr == 0) {
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std::cerr << "Could not resolve external global address: "
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<< GV->getName() << "\n";
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abort();
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}
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} else {
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// If the global hasn't been emitted to memory yet, allocate space. We will
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// actually initialize the global after current function has finished
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// compilation.
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Ptr =new char[getTargetData().getTypeSize(GV->getType()->getElementType())];
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PendingGlobals.push_back(GV);
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}
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addGlobalMapping(GV, Ptr);
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return Ptr;
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}
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/// recompileAndRelinkFunction - This method is used to force a function
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/// which has already been compiled, to be compiled again, possibly
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/// after it has been modified. Then the entry to the old copy is overwritten
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/// with a branch to the new copy. If there was no old copy, this acts
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/// just like JIT::getPointerToFunction().
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///
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void *JIT::recompileAndRelinkFunction(Function *F) {
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void *OldAddr = getPointerToGlobalIfAvailable(F);
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// If it's not already compiled there is no reason to patch it up.
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if (OldAddr == 0) { return getPointerToFunction(F); }
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// Delete the old function mapping.
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addGlobalMapping(F, 0);
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// Recodegen the function
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runJITOnFunction(F);
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// Update state, forward the old function to the new function.
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void *Addr = getPointerToGlobalIfAvailable(F);
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assert(Addr && "Code generation didn't add function to GlobalAddress table!");
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TJI.replaceMachineCodeForFunction(OldAddr, Addr);
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return Addr;
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}
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