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+//===-- JIT.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 bitcode in an efficient manner.
+//
+//===----------------------------------------------------------------------===//
+
+#include "JIT.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Function.h"
+#include "llvm/GlobalVariable.h"
+#include "llvm/Instructions.h"
+#include "llvm/ModuleProvider.h"
+#include "llvm/CodeGen/MachineCodeEmitter.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/ExecutionEngine/GenericValue.h"
+#include "llvm/Support/MutexGuard.h"
+#include "llvm/System/DynamicLibrary.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetJITInfo.h"
+using namespace llvm;
+
+#ifdef __APPLE__
+#include <AvailabilityMacros.h>
+#if defined(MAC_OS_X_VERSION_10_4) && \
+ ((MAC_OS_X_VERSION_MIN_REQUIRED > MAC_OS_X_VERSION_10_4) || \
+ (MAC_OS_X_VERSION_MIN_REQUIRED == MAC_OS_X_VERSION_10_4 && \
+ __APPLE_CC__ >= 5330))
+// __dso_handle is resolved by Mac OS X dynamic linker.
+extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
+#endif
+#endif
+
+static struct RegisterJIT {
+ RegisterJIT() { JIT::Register(); }
+} JITRegistrator;
+
+namespace llvm {
+ void LinkInJIT() {
+ }
+}
+
+JIT::JIT(ModuleProvider *MP, TargetMachine &tm, TargetJITInfo &tji)
+ : ExecutionEngine(MP), TM(tm), TJI(tji), jitstate(MP) {
+ setTargetData(TM.getTargetData());
+
+ // Initialize MCE
+ MCE = createEmitter(*this);
+
+ // Add target data
+ MutexGuard locked(lock);
+ FunctionPassManager &PM = jitstate.getPM(locked);
+ PM.add(new TargetData(*TM.getTargetData()));
+
+ // Turn the machine code intermediate representation into bytes in memory that
+ // may be executed.
+ if (TM.addPassesToEmitMachineCode(PM, *MCE, false /*fast*/)) {
+ cerr << "Target does not support machine code emission!\n";
+ abort();
+ }
+
+ // Initialize passes.
+ PM.doInitialization();
+}
+
+JIT::~JIT() {
+ delete MCE;
+ delete &TM;
+}
+
+/// run - Start execution with the specified function and arguments.
+///
+GenericValue JIT::runFunction(Function *F,
+ const std::vector<GenericValue> &ArgValues) {
+ assert(F && "Function *F was null at entry to run()");
+
+ void *FPtr = getPointerToFunction(F);
+ assert(FPtr && "Pointer to fn's code was null after getPointerToFunction");
+ const FunctionType *FTy = F->getFunctionType();
+ const Type *RetTy = FTy->getReturnType();
+
+ assert((FTy->getNumParams() <= ArgValues.size() || FTy->isVarArg()) &&
+ "Too many arguments passed into function!");
+ assert(FTy->getNumParams() == ArgValues.size() &&
+ "This doesn't support passing arguments through varargs (yet)!");
+
+ // Handle some common cases first. These cases correspond to common `main'
+ // prototypes.
+ if (RetTy == Type::Int32Ty || RetTy == Type::Int32Ty || RetTy == Type::VoidTy) {
+ switch (ArgValues.size()) {
+ case 3:
+ if ((FTy->getParamType(0) == Type::Int32Ty ||
+ FTy->getParamType(0) == Type::Int32Ty) &&
+ isa<PointerType>(FTy->getParamType(1)) &&
+ isa<PointerType>(FTy->getParamType(2))) {
+ int (*PF)(int, char **, const char **) =
+ (int(*)(int, char **, const char **))(intptr_t)FPtr;
+
+ // Call the function.
+ GenericValue rv;
+ rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
+ (char **)GVTOP(ArgValues[1]),
+ (const char **)GVTOP(ArgValues[2])));
+ return rv;
+ }
+ break;
+ case 2:
+ if ((FTy->getParamType(0) == Type::Int32Ty ||
+ FTy->getParamType(0) == Type::Int32Ty) &&
+ isa<PointerType>(FTy->getParamType(1))) {
+ int (*PF)(int, char **) = (int(*)(int, char **))(intptr_t)FPtr;
+
+ // Call the function.
+ GenericValue rv;
+ rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
+ (char **)GVTOP(ArgValues[1])));
+ return rv;
+ }
+ break;
+ case 1:
+ if (FTy->getNumParams() == 1 &&
+ (FTy->getParamType(0) == Type::Int32Ty ||
+ FTy->getParamType(0) == Type::Int32Ty)) {
+ GenericValue rv;
+ int (*PF)(int) = (int(*)(int))(intptr_t)FPtr;
+ rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue()));
+ return rv;
+ }
+ break;
+ }
+ }
+
+ // Handle cases where no arguments are passed first.
+ if (ArgValues.empty()) {
+ GenericValue rv;
+ switch (RetTy->getTypeID()) {
+ default: assert(0 && "Unknown return type for function call!");
+ case Type::IntegerTyID: {
+ unsigned BitWidth = cast<IntegerType>(RetTy)->getBitWidth();
+ if (BitWidth == 1)
+ rv.IntVal = APInt(BitWidth, ((bool(*)())(intptr_t)FPtr)());
+ else if (BitWidth <= 8)
+ rv.IntVal = APInt(BitWidth, ((char(*)())(intptr_t)FPtr)());
+ else if (BitWidth <= 16)
+ rv.IntVal = APInt(BitWidth, ((short(*)())(intptr_t)FPtr)());
+ else if (BitWidth <= 32)
+ rv.IntVal = APInt(BitWidth, ((int(*)())(intptr_t)FPtr)());
+ else if (BitWidth <= 64)
+ rv.IntVal = APInt(BitWidth, ((int64_t(*)())(intptr_t)FPtr)());
+ else
+ assert(0 && "Integer types > 64 bits not supported");
+ return rv;
+ }
+ case Type::VoidTyID:
+ rv.IntVal = APInt(32, ((int(*)())(intptr_t)FPtr)());
+ return rv;
+ case Type::FloatTyID:
+ rv.FloatVal = ((float(*)())(intptr_t)FPtr)();
+ return rv;
+ case Type::DoubleTyID:
+ rv.DoubleVal = ((double(*)())(intptr_t)FPtr)();
+ return rv;
+ case Type::PointerTyID:
+ return PTOGV(((void*(*)())(intptr_t)FPtr)());
+ }
+ }
+
+ // Okay, this is not one of our quick and easy cases. Because we don't have a
+ // full FFI, we have to codegen a nullary stub function that just calls the
+ // function we are interested in, passing in constants for all of the
+ // arguments. Make this function and return.
+
+ // First, create the function.
+ FunctionType *STy=FunctionType::get(RetTy, std::vector<const Type*>(), false);
+ Function *Stub = new Function(STy, Function::InternalLinkage, "",
+ F->getParent());
+
+ // Insert a basic block.
+ BasicBlock *StubBB = new BasicBlock("", Stub);
+
+ // Convert all of the GenericValue arguments over to constants. Note that we
+ // currently don't support varargs.
+ SmallVector<Value*, 8> Args;
+ for (unsigned i = 0, e = ArgValues.size(); i != e; ++i) {
+ Constant *C = 0;
+ const Type *ArgTy = FTy->getParamType(i);
+ const GenericValue &AV = ArgValues[i];
+ switch (ArgTy->getTypeID()) {
+ default: assert(0 && "Unknown argument type for function call!");
+ case Type::IntegerTyID: C = ConstantInt::get(AV.IntVal); break;
+ case Type::FloatTyID: C = ConstantFP ::get(ArgTy, AV.FloatVal); break;
+ case Type::DoubleTyID: C = ConstantFP ::get(ArgTy, AV.DoubleVal); break;
+ case Type::PointerTyID:
+ void *ArgPtr = GVTOP(AV);
+ if (sizeof(void*) == 4) {
+ C = ConstantInt::get(Type::Int32Ty, (int)(intptr_t)ArgPtr);
+ } else {
+ C = ConstantInt::get(Type::Int64Ty, (intptr_t)ArgPtr);
+ }
+ C = ConstantExpr::getIntToPtr(C, ArgTy); // Cast the integer to pointer
+ break;
+ }
+ Args.push_back(C);
+ }
+
+ CallInst *TheCall = new CallInst(F, &Args[0], Args.size(), "", StubBB);
+ TheCall->setTailCall();
+ if (TheCall->getType() != Type::VoidTy)
+ new ReturnInst(TheCall, StubBB); // Return result of the call.
+ else
+ new ReturnInst(StubBB); // Just return void.
+
+ // Finally, return the value returned by our nullary stub function.
+ return runFunction(Stub, std::vector<GenericValue>());
+}
+
+/// 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 JIT::runJITOnFunction(Function *F) {
+ static bool isAlreadyCodeGenerating = false;
+ assert(!isAlreadyCodeGenerating && "Error: Recursive compilation detected!");
+
+ MutexGuard locked(lock);
+
+ // JIT the function
+ isAlreadyCodeGenerating = true;
+ jitstate.getPM(locked).run(*F);
+ isAlreadyCodeGenerating = false;
+
+ // If the function referred to a global variable that had not yet been
+ // emitted, it allocates memory for the global, but doesn't emit it yet. Emit
+ // all of these globals now.
+ while (!jitstate.getPendingGlobals(locked).empty()) {
+ const GlobalVariable *GV = jitstate.getPendingGlobals(locked).back();
+ jitstate.getPendingGlobals(locked).pop_back();
+ EmitGlobalVariable(GV);
+ }
+}
+
+/// getPointerToFunction - This method is used to get the address of the
+/// specified function, compiling it if neccesary.
+///
+void *JIT::getPointerToFunction(Function *F) {
+ MutexGuard locked(lock);
+
+ if (void *Addr = getPointerToGlobalIfAvailable(F))
+ return Addr; // Check if function already code gen'd
+
+ // Make sure we read in the function if it exists in this Module.
+ if (F->hasNotBeenReadFromBitcode()) {
+ // Determine the module provider this function is provided by.
+ Module *M = F->getParent();
+ ModuleProvider *MP = 0;
+ for (unsigned i = 0, e = Modules.size(); i != e; ++i) {
+ if (Modules[i]->getModule() == M) {
+ MP = Modules[i];
+ break;
+ }
+ }
+ assert(MP && "Function isn't in a module we know about!");
+
+ std::string ErrorMsg;
+ if (MP->materializeFunction(F, &ErrorMsg)) {
+ cerr << "Error reading function '" << F->getName()
+ << "' from bitcode file: " << ErrorMsg << "\n";
+ abort();
+ }
+ }
+
+ if (F->isDeclaration()) {
+ void *Addr = getPointerToNamedFunction(F->getName());
+ addGlobalMapping(F, Addr);
+ return Addr;
+ }
+
+ runJITOnFunction(F);
+
+ void *Addr = getPointerToGlobalIfAvailable(F);
+ assert(Addr && "Code generation didn't add function to GlobalAddress table!");
+ return Addr;
+}
+
+/// getOrEmitGlobalVariable - Return the address of the specified global
+/// variable, possibly emitting it to memory if needed. This is used by the
+/// Emitter.
+void *JIT::getOrEmitGlobalVariable(const GlobalVariable *GV) {
+ MutexGuard locked(lock);
+
+ void *Ptr = getPointerToGlobalIfAvailable(GV);
+ if (Ptr) return Ptr;
+
+ // If the global is external, just remember the address.
+ if (GV->isDeclaration()) {
+#if defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_4) && \
+ ((MAC_OS_X_VERSION_MIN_REQUIRED > MAC_OS_X_VERSION_10_4) || \
+ (MAC_OS_X_VERSION_MIN_REQUIRED == MAC_OS_X_VERSION_10_4 && \
+ __APPLE_CC__ >= 5330))
+ // Apple gcc defaults to -fuse-cxa-atexit (i.e. calls __cxa_atexit instead
+ // of atexit). It passes the address of linker generated symbol __dso_handle
+ // to the function.
+ // This configuration change happened at version 5330.
+ if (GV->getName() == "__dso_handle")
+ return (void*)&__dso_handle;
+#endif
+ Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(GV->getName().c_str());
+ if (Ptr == 0) {
+ cerr << "Could not resolve external global address: "
+ << GV->getName() << "\n";
+ abort();
+ }
+ } else {
+ // If the global hasn't been emitted to memory yet, allocate space. We will
+ // actually initialize the global after current function has finished
+ // compilation.
+ const Type *GlobalType = GV->getType()->getElementType();
+ size_t S = getTargetData()->getTypeSize(GlobalType);
+ size_t A = getTargetData()->getPrefTypeAlignment(GlobalType);
+ if (A <= 8) {
+ Ptr = malloc(S);
+ } else {
+ // Allocate S+A bytes of memory, then use an aligned pointer within that
+ // space.
+ Ptr = malloc(S+A);
+ unsigned MisAligned = ((intptr_t)Ptr & (A-1));
+ Ptr = (char*)Ptr + (MisAligned ? (A-MisAligned) : 0);
+ }
+ jitstate.getPendingGlobals(locked).push_back(GV);
+ }
+ addGlobalMapping(GV, Ptr);
+ return Ptr;
+}
+
+
+/// 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 JIT::getPointerToFunction().
+///
+void *JIT::recompileAndRelinkFunction(Function *F) {
+ void *OldAddr = getPointerToGlobalIfAvailable(F);
+
+ // If it's not already compiled there is no reason to patch it up.
+ if (OldAddr == 0) { return getPointerToFunction(F); }
+
+ // Delete the old function mapping.
+ addGlobalMapping(F, 0);
+
+ // Recodegen the function
+ runJITOnFunction(F);
+
+ // Update state, forward the old function to the new function.
+ void *Addr = getPointerToGlobalIfAvailable(F);
+ assert(Addr && "Code generation didn't add function to GlobalAddress table!");
+ TJI.replaceMachineCodeForFunction(OldAddr, Addr);
+ return Addr;
+}
+
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