Allow for specification of which JIT to run on the commandline.

`lli -march=x86' or `lli -march=sparc' will forcefully select the JIT even on a
different platform. Running lli without the -march option will select the JIT
for the platform that it's currently running on.

Pro: can test Sparc JIT (debug printing mode) on X86 -- faster to compile/link
LLVM source base to test changes.
Con: Linking lli on x86 now pulls in all the Sparc libs -> longer link time
(but X86 can bear it, right?)

In the future, perhaps this should be a ./configure option to enable/disable
target JITting...


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6360 91177308-0d34-0410-b5e6-96231b3b80d8

lib/ExecutionEngine/JIT/JIT.cpp

@@ -9,28 +9,65 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetMachineImpls.h"
 #include "llvm/Module.h"
+#include "Support/CommandLine.h"
+
+namespace {
+  cl::opt<std::string>
+  Arch("march", cl::desc("Architecture: `x86' or `sparc'"), cl::Prefix,
+       cl::value_desc("machine architecture"));
+  
+  static std::string DefaultArch = 
+#if defined(i386) || defined(__i386__) || defined(__x86__)
+  "x86";
+#elif defined(sparc) || defined(__sparc__) || defined(__sparcv9)
+  "sparc";
+#else
+  "";
+#endif
+
+}
 
 
 /// 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!");
+  
+  TargetMachine* (*TargetMachineAllocator)(unsigned) = 0;
+  if (Arch == "")
+    Arch = DefaultArch;
 
-  // Create the virtual machine object...
-  return new VM(M, Target);
+  // Allow a command-line switch to override what *should* be the default target
+  // machine for this platform. This allows for debugging a Sparc JIT on X86 --
+  // our X86 machines are much faster at recompiling LLVM and linking lli.
+  if (Arch == "x86") {
+    TargetMachineAllocator = allocateX86TargetMachine;
+  } else if (Arch == "sparc") {
+    TargetMachineAllocator = allocateSparcTargetMachine;
+  }
+
+  if (TargetMachineAllocator) {
+    // Allocate a target...
+    TargetMachine *Target = (*TargetMachineAllocator)(Config);
+    assert(Target && "Could not allocate target machine!");
+
+    // Create the virtual machine object...
+    return new VM(M, Target);
+  } else {
+    return 0;
+  }
 }
 
 VM::VM(Module *M, TargetMachine *tm) : ExecutionEngine(M), TM(*tm) {
   setTargetData(TM.getTargetData());
-  MCE = createEmitter(*this);  // Initialize MCE
+
+  // Initialize MCE
+  if (Arch == "x86") {
+    MCE = createX86Emitter(*this);
+  } else if (Arch == "sparc") {
+    MCE = createSparcEmitter(*this);
+  }
+
   setupPassManager();
   registerCallback();
   emitGlobals();

lib/ExecutionEngine/JIT/JIT.h

@@ -62,7 +62,8 @@ public:
   static void runAtExitHandlers();
 
 private:
-  static MachineCodeEmitter *createEmitter(VM &V);
+  static MachineCodeEmitter *createX86Emitter(VM &V);
+  static MachineCodeEmitter *createSparcEmitter(VM &V);
   void setupPassManager();
   void *getPointerToFunction(const Function *F);
 

lib/ExecutionEngine/JIT/JITEmitter.cpp

@@ -48,7 +48,7 @@ namespace {
   };
 }
 
-MachineCodeEmitter *VM::createEmitter(VM &V) {
+MachineCodeEmitter *VM::createX86Emitter(VM &V) {
   return new Emitter(V);
 }
 

lib/ExecutionEngine/JIT/SparcEmitter.cpp

@@ -0,0 +1,218 @@
+//===-- SparcEmitter.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/CodeGen/MachineConstantPool.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Function.h"
+#include "Support/Statistic.h"
+// FIXME
+#include "../../../lib/Target/Sparc/SparcV9CodeEmitter.h"
+
+namespace {
+  Statistic<> NumBytes("jello", "Number of bytes of machine code compiled");
+
+  class SparcEmitter : public MachineCodeEmitter {
+    VM &TheVM;
+
+    unsigned char *CurBlock, *CurByte;
+
+    // When outputting a function stub in the context of some other function, we
+    // save CurBlock and CurByte here.
+    unsigned char *SavedCurBlock, *SavedCurByte;
+    
+    std::vector<std::pair<BasicBlock*,
+                          std::pair<unsigned*,MachineInstr*> > > BBRefs;
+    std::map<BasicBlock*, unsigned> BBLocations;
+    std::vector<void*> ConstantPoolAddresses;
+  public:
+    SparcEmitter(VM &vm) : TheVM(vm) {}
+
+    virtual void startFunction(MachineFunction &F);
+    virtual void finishFunction(MachineFunction &F);
+    virtual void emitConstantPool(MachineConstantPool *MCP);
+    virtual void startBasicBlock(MachineBasicBlock &BB);
+    virtual void startFunctionStub(const Function &F, unsigned StubSize);
+    virtual void* finishFunctionStub(const Function &F);
+    virtual void emitByte(unsigned char B);
+    virtual void emitPCRelativeDisp(Value *V);
+    virtual void emitGlobalAddress(GlobalValue *V, bool isPCRelative);
+    virtual void emitGlobalAddress(const std::string &Name, bool isPCRelative);
+    virtual void emitFunctionConstantValueAddress(unsigned ConstantNum,
+						  int Offset);
+
+    virtual void saveBBreference(BasicBlock *BB, MachineInstr &MI);
+
+  private:
+    void emitAddress(void *Addr, bool isPCRelative);
+  };
+}
+
+MachineCodeEmitter *VM::createSparcEmitter(VM &V) {
+  return new SparcEmitter(V);
+}
+
+
+#define _POSIX_MAPPED_FILES
+#include <unistd.h>
+#include <sys/mman.h>
+
+// FIXME: This should be rewritten to support a real memory manager for
+// executable memory pages!
+static void *getMemory(unsigned NumPages) {
+  return mmap(0, 4096*NumPages, PROT_READ|PROT_WRITE|PROT_EXEC,
+              MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
+}
+
+
+void SparcEmitter::startFunction(MachineFunction &F) {
+  CurBlock = (unsigned char *)getMemory(8);
+  CurByte = CurBlock;  // Start writing at the beginning of the fn.
+  TheVM.addGlobalMapping(F.getFunction(), CurBlock);
+}
+
+void SparcEmitter::finishFunction(MachineFunction &F) {
+  ConstantPoolAddresses.clear();
+  for (unsigned i = 0, e = BBRefs.size(); i != e; ++i) {
+    // Re-write branches to BasicBlocks for the entire function
+    unsigned Location = BBLocations[BBRefs[i].first];
+    unsigned *Ref = BBRefs[i].second.first;
+    MachineInstr *MI = BBRefs[i].second.second;
+    for (unsigned i=0, e = MI->getNumOperands(); i != e; ++i) {
+      MachineOperand &op = MI->getOperand(i);
+      if (op.isImmediate()) {
+        MI->SetMachineOperandConst(i, op.getType(), Location);
+        break;
+      }
+    }
+    unsigned fixedInstr = SparcV9CodeEmitter::getBinaryCodeForInstr(*MI);
+    *Ref = fixedInstr;
+  }
+  BBRefs.clear();
+  BBLocations.clear();
+
+  NumBytes += CurByte-CurBlock;
+
+  DEBUG(std::cerr << "Finished CodeGen of [0x" << std::hex
+                  << (unsigned)(intptr_t)CurBlock
+                  << std::dec << "] Function: " << F.getFunction()->getName()
+                  << ": " << CurByte-CurBlock << " bytes of text\n");
+}
+
+void SparcEmitter::emitConstantPool(MachineConstantPool *MCP) {
+  const std::vector<Constant*> &Constants = MCP->getConstants();
+  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
+    // For now we just allocate some memory on the heap, this can be
+    // dramatically improved.
+    const Type *Ty = ((Value*)Constants[i])->getType();
+    void *Addr = malloc(TheVM.getTargetData().getTypeSize(Ty));
+    TheVM.InitializeMemory(Constants[i], Addr);
+    ConstantPoolAddresses.push_back(Addr);
+  }
+}
+
+
+void SparcEmitter::startBasicBlock(MachineBasicBlock &BB) {
+  BBLocations[BB.getBasicBlock()] = (unsigned)(intptr_t)CurByte;
+}
+
+
+void SparcEmitter::startFunctionStub(const Function &F, unsigned StubSize) {
+  SavedCurBlock = CurBlock;  SavedCurByte = CurByte;
+  // FIXME: this is a huge waste of memory.
+  CurBlock = (unsigned char *)getMemory((StubSize+4095)/4096);
+  CurByte = CurBlock;  // Start writing at the beginning of the fn.
+}
+
+void *SparcEmitter::finishFunctionStub(const Function &F) {
+  NumBytes += CurByte-CurBlock;
+  DEBUG(std::cerr << "Finished CodeGen of [0x" << std::hex
+                  << (unsigned)(intptr_t)CurBlock
+                  << std::dec << "] Function stub for: " << F.getName()
+                  << ": " << CurByte-CurBlock << " bytes of text\n");
+  std::swap(CurBlock, SavedCurBlock);
+  CurByte = SavedCurByte;
+  return SavedCurBlock;
+}
+
+void SparcEmitter::emitByte(unsigned char B) {
+  *CurByte++ = B;   // Write the byte to memory
+}
+
+// BasicBlock -> pair<memloc, MachineInstr>
+// when the BB is emitted, machineinstr is modified with then-currbyte, 
+// processed with MCE, and written out at memloc.
+void SparcEmitter::saveBBreference(BasicBlock *BB, MachineInstr &MI) {
+  BBRefs.push_back(std::make_pair(BB, std::make_pair((unsigned*)CurByte, &MI)));
+}
+
+
+// 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.
+//
+// BasicBlock -> pair<memloc, MachineInstr>
+// when the BB is emitted, machineinstr is modified with then-currbyte, 
+// processed with MCE, and written out at memloc.
+
+void SparcEmitter::emitPCRelativeDisp(Value *V) {
+#if 0
+  BasicBlock *BB = cast<BasicBlock>(V);     // Keep track of reference...
+  BBRefs.push_back(std::make_pair(BB, (unsigned*)CurByte));
+  CurByte += 4;
+#endif
+}
+
+// emitAddress - Emit an address in either direct or PCRelative form...
+//
+void SparcEmitter::emitAddress(void *Addr, bool isPCRelative) {
+#if 0
+  if (isPCRelative) {
+    *(intptr_t*)CurByte = (intptr_t)Addr - (intptr_t)CurByte-4;
+  } else {
+    *(void**)CurByte = Addr;
+  }
+  CurByte += 4;
+#endif
+}
+
+void SparcEmitter::emitGlobalAddress(GlobalValue *V, bool isPCRelative) {
+  if (isPCRelative) { // must be a call, this is a major hack!
+    // Try looking up the function to see if it is already compiled!
+    if (void *Addr = TheVM.getPointerToGlobalIfAvailable(V)) {
+      emitAddress(Addr, isPCRelative);
+    } else {  // Function has not yet been code generated!
+      TheVM.addFunctionRef(CurByte, cast<Function>(V));
+
+      // Delayed resolution...
+      emitAddress((void*)VM::CompilationCallback, isPCRelative);
+    }
+  } else {
+    emitAddress(TheVM.getPointerToGlobal(V), isPCRelative);
+  }
+}
+
+void SparcEmitter::emitGlobalAddress(const std::string &Name, bool isPCRelative)
+{
+#if 0
+  emitAddress(TheVM.getPointerToNamedFunction(Name), isPCRelative);
+#endif
+}
+
+void SparcEmitter::emitFunctionConstantValueAddress(unsigned ConstantNum,
+					       int Offset) {
+  assert(ConstantNum < ConstantPoolAddresses.size() &&
+	 "Invalid ConstantPoolIndex!");
+  *(void**)CurByte = (char*)ConstantPoolAddresses[ConstantNum]+Offset;
+  CurByte += 4;
+}

lib/ExecutionEngine/JIT/VM.h

@@ -62,7 +62,8 @@ public:
   static void runAtExitHandlers();
 
 private:
-  static MachineCodeEmitter *createEmitter(VM &V);
+  static MachineCodeEmitter *createX86Emitter(VM &V);
+  static MachineCodeEmitter *createSparcEmitter(VM &V);
   void setupPassManager();
   void *getPointerToFunction(const Function *F);