Initial checkin of new LLI with JIT compiler
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5126 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ExecutionEngine/JIT/Callback.cpp b/lib/ExecutionEngine/JIT/Callback.cpp
new file mode 100644
index 0000000..b843e10
--- /dev/null
+++ b/lib/ExecutionEngine/JIT/Callback.cpp
@@ -0,0 +1,62 @@
+//===-- Callback.cpp - Trap handler for function resolution ---------------===//
+//
+// This file defines the SIGSEGV handler which is invoked when a reference to a
+// non-codegen'd function is found.
+//
+//===----------------------------------------------------------------------===//
+
+#include "VM.h"
+#include "Support/Statistic.h"
+#include <signal.h>
+#include <ucontext.h>
+#include <iostream>
+
+static VM *TheVM = 0;
+
+static void TrapHandler(int TN, siginfo_t *SI, ucontext_t *ucp) {
+ assert(TN == SIGSEGV && "Should be SIGSEGV!");
+
+#ifdef REG_EIP /* this code does not compile on Sparc! */
+ if (SI->si_code != SEGV_MAPERR || SI->si_addr != 0 ||
+ ucp->uc_mcontext.gregs[REG_EIP] != 0) {
+ std::cerr << "Bad SEGV encountered!\n";
+ abort();
+ }
+
+ // The call instruction should have pushed the return value onto the stack...
+ unsigned RefAddr = *(unsigned*)ucp->uc_mcontext.gregs[REG_ESP];
+ RefAddr -= 4; // Backtrack to the reference itself...
+
+ DEBUG(std::cerr << "In SEGV handler! Addr=0x" << std::hex << RefAddr
+ << " ESP=0x" << ucp->uc_mcontext.gregs[REG_ESP] << std::dec
+ << ": Resolving call to function: "
+ << TheVM->getFunctionReferencedName((void*)RefAddr) << "\n");
+
+ // Sanity check to make sure this really is a call instruction...
+ assert(((unsigned char*)RefAddr)[-1] == 0xE8 && "Not a call instr!");
+
+ unsigned NewVal = (unsigned)TheVM->resolveFunctionReference((void*)RefAddr);
+
+ // Rewrite the call target... so that we don't fault every time we execute
+ // the call.
+ *(unsigned*)RefAddr = NewVal-RefAddr-4;
+
+ // Change the instruction pointer to be the real target of the call...
+ ucp->uc_mcontext.gregs[REG_EIP] = NewVal;
+
+#endif
+}
+
+
+void VM::registerCallback() {
+ TheVM = this;
+
+ // Register the signal handler...
+ struct sigaction SA;
+ SA.sa_sigaction = (void (*)(int, siginfo_t*, void*))TrapHandler;
+ sigfillset(&SA.sa_mask); // Block all signals while codegen'ing
+ SA.sa_flags = SA_NOCLDSTOP|SA_SIGINFO; // Get siginfo
+ sigaction(SIGSEGV, &SA, 0); // Install the handler
+}
+
+
diff --git a/lib/ExecutionEngine/JIT/GlobalVars.cpp b/lib/ExecutionEngine/JIT/GlobalVars.cpp
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/lib/ExecutionEngine/JIT/GlobalVars.cpp
diff --git a/lib/ExecutionEngine/JIT/JIT.cpp b/lib/ExecutionEngine/JIT/JIT.cpp
new file mode 100644
index 0000000..b2b56a6
--- /dev/null
+++ b/lib/ExecutionEngine/JIT/JIT.cpp
@@ -0,0 +1,53 @@
+//===-- JIT.cpp - LLVM Just in Time Compiler ------------------------------===//
+//
+// This file implements the top-level support for creating a Just-In-Time
+// compiler for the current architecture.
+//
+//===----------------------------------------------------------------------===//
+
+#include "VM.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetMachineImpls.h"
+#include "llvm/Module.h"
+
+
+/// createJIT - Create an return a new JIT compiler if there is one available
+/// for the current target. Otherwise it returns null.
+///
+ExecutionEngine *ExecutionEngine::createJIT(Module *M, unsigned Config) {
+ // FIXME: This should be controlled by which subdirectory gets linked in!
+#if !defined(i386) && !defined(__i386__) && !defined(__x86__)
+ return 0;
+#endif
+ // Allocate a target... in the future this will be controllable on the
+ // command line.
+ TargetMachine *Target = allocateX86TargetMachine(Config);
+ assert(Target && "Could not allocate X86 target machine!");
+
+ // Create the virtual machine object...
+ return new VM(M, Target);
+}
+
+VM::VM(Module *M, TargetMachine *tm) : ExecutionEngine(M), TM(*tm) {
+ setTargetData(TM.getTargetData());
+ MCE = createEmitter(*this); // Initialize MCE
+ setupPassManager();
+ registerCallback();
+}
+
+int VM::run(const std::string &FnName, const std::vector<std::string> &Args) {
+ Function *F = getModule().getNamedFunction(FnName);
+ if (F == 0) {
+ std::cerr << "Could not find function '" << FnName <<"' in module!\n";
+ return 1;
+ }
+
+ int(*PF)(int, char**) = (int(*)(int, char**))getPointerToFunction(F);
+ assert(PF != 0 && "Null pointer to function?");
+
+ // Build an argv vector...
+ char **Argv = (char**)CreateArgv(Args);
+
+ // Call the main function...
+ return PF(Args.size(), Argv);
+}
diff --git a/lib/ExecutionEngine/JIT/JITEmitter.cpp b/lib/ExecutionEngine/JIT/JITEmitter.cpp
new file mode 100644
index 0000000..253a229
--- /dev/null
+++ b/lib/ExecutionEngine/JIT/JITEmitter.cpp
@@ -0,0 +1,107 @@
+//===-- Emitter.cpp - Write machine code to executable memory -------------===//
+//
+// This file defines a MachineCodeEmitter object that is used by Jello to write
+// machine code to memory and remember where relocatable values lie.
+//
+//===----------------------------------------------------------------------===//
+
+#include "VM.h"
+#include "llvm/CodeGen/MachineCodeEmitter.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/Function.h"
+#include "Support/Statistic.h"
+
+namespace {
+ Statistic<> NumBytes("jello", "Number of bytes of machine code compiled");
+
+ class Emitter : public MachineCodeEmitter {
+ VM &TheVM;
+
+ unsigned char *CurBlock;
+ unsigned char *CurByte;
+
+ std::vector<std::pair<BasicBlock*, unsigned *> > BBRefs;
+ std::map<BasicBlock*, unsigned> BBLocations;
+ public:
+ Emitter(VM &vm) : TheVM(vm) {}
+
+ virtual void startFunction(MachineFunction &F);
+ virtual void finishFunction(MachineFunction &F);
+ virtual void startBasicBlock(MachineBasicBlock &BB);
+ virtual void emitByte(unsigned char B);
+ virtual void emitPCRelativeDisp(Value *V);
+ virtual void emitGlobalAddress(GlobalValue *V);
+ };
+}
+
+MachineCodeEmitter *VM::createEmitter(VM &V) {
+ return new Emitter(V);
+}
+
+
+#define _POSIX_MAPPED_FILES
+#include <unistd.h>
+#include <sys/mman.h>
+
+static void *getMemory() {
+ return mmap(0, 4096*2, PROT_READ|PROT_WRITE|PROT_EXEC,
+ MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
+}
+
+
+void Emitter::startFunction(MachineFunction &F) {
+ CurBlock = (unsigned char *)getMemory();
+ CurByte = CurBlock; // Start writing at the beginning of the fn.
+ TheVM.addGlobalMapping(F.getFunction(), CurBlock);
+}
+
+void Emitter::finishFunction(MachineFunction &F) {
+ for (unsigned i = 0, e = BBRefs.size(); i != e; ++i) {
+ unsigned Location = BBLocations[BBRefs[i].first];
+ unsigned *Ref = BBRefs[i].second;
+ *Ref = Location-(unsigned)Ref-4;
+ }
+ BBRefs.clear();
+ BBLocations.clear();
+
+ NumBytes += CurByte-CurBlock;
+
+ DEBUG(std::cerr << "Finished CodeGen of [" << std::hex << (unsigned)CurBlock
+ << std::dec << "] Function: " << F.getFunction()->getName()
+ << ": " << CurByte-CurBlock << " bytes of text\n");
+}
+
+void Emitter::startBasicBlock(MachineBasicBlock &BB) {
+ BBLocations[BB.getBasicBlock()] = (unsigned)CurByte;
+}
+
+
+void Emitter::emitByte(unsigned char B) {
+ *CurByte++ = B; // Write the byte to memory
+}
+
+
+// emitPCRelativeDisp - For functions, just output a displacement that will
+// cause a reference to the zero page, which will cause a seg-fault, causing
+// things to get resolved on demand. Keep track of these markers.
+//
+// For basic block references, keep track of where the references are so they
+// may be patched up when the basic block is defined.
+//
+void Emitter::emitPCRelativeDisp(Value *V) {
+ if (Function *F = dyn_cast<Function>(V)) {
+ TheVM.addFunctionRef(CurByte, F);
+ unsigned ZeroAddr = -(unsigned)CurByte-4; // Calculate displacement to null
+ *(unsigned*)CurByte = ZeroAddr; // 4 byte offset
+ CurByte += 4;
+ } else {
+ BasicBlock *BB = cast<BasicBlock>(V); // Keep track of reference...
+ BBRefs.push_back(std::make_pair(BB, (unsigned*)CurByte));
+ CurByte += 4;
+ }
+}
+
+void Emitter::emitGlobalAddress(GlobalValue *V) {
+ *(void**)CurByte = TheVM.getPointerToGlobal(V);
+ CurByte += 4;
+}
diff --git a/lib/ExecutionEngine/JIT/Makefile b/lib/ExecutionEngine/JIT/Makefile
new file mode 100644
index 0000000..bc3f709
--- /dev/null
+++ b/lib/ExecutionEngine/JIT/Makefile
@@ -0,0 +1,4 @@
+LEVEL = ../../..
+LIBRARYNAME = lli-jit
+
+include $(LEVEL)/Makefile.common
diff --git a/lib/ExecutionEngine/JIT/VM.cpp b/lib/ExecutionEngine/JIT/VM.cpp
new file mode 100644
index 0000000..f66d4d7
--- /dev/null
+++ b/lib/ExecutionEngine/JIT/VM.cpp
@@ -0,0 +1,84 @@
+//===-- jello.cpp - LLVM Just in Time Compiler ----------------------------===//
+//
+// 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/Target/TargetMachine.h"
+#include "llvm/CodeGen/MachineCodeEmitter.h"
+#include "llvm/Function.h"
+#include <dlfcn.h> // dlsym access
+
+
+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();
+ }
+}
+
+void *VM::resolveFunctionReference(void *RefAddr) {
+ Function *F = FunctionRefs[RefAddr];
+ assert(F && "Reference address not known!");
+
+ void *Addr = getPointerToFunction(F);
+ assert(Addr && "Pointer to function unknown!");
+
+ FunctionRefs.erase(RefAddr);
+ return Addr;
+}
+
+const std::string &VM::getFunctionReferencedName(void *RefAddr) {
+ return FunctionRefs[RefAddr]->getName();
+}
+
+static void NoopFn() {}
+
+/// getPointerToFunction - This method is used to get the address of the
+/// specified function, compiling it if neccesary.
+///
+void *VM::getPointerToFunction(const Function *F) {
+ void *&Addr = GlobalAddress[F]; // Function already code gen'd
+ if (Addr) return Addr;
+
+ if (F->isExternal()) {
+ // If it's an external function, look it up in the process image...
+ void *Ptr = dlsym(0, F->getName().c_str());
+ if (Ptr == 0) {
+ std::cerr << "WARNING: Cannot resolve fn '" << F->getName()
+ << "' using a dummy noop function instead!\n";
+ Ptr = (void*)NoopFn;
+ }
+
+ return Addr = Ptr;
+ }
+
+ // JIT all of the functions in the module. Eventually this will JIT functions
+ // on demand. This has the effect of populating all of the non-external
+ // functions into the GlobalAddress table.
+ PM.run(getModule());
+
+ assert(Addr && "Code generation didn't add function to GlobalAddress table!");
+ return Addr;
+}