Initial revision

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Bytecode/Writer/Writer.cpp

@@ -0,0 +1,182 @@
+//===-- Writer.cpp - Library for writing VM bytecode files -------*- C++ -*--=//
+//
+// This library implements the functionality defined in llvm/Bytecode/Writer.h
+//
+// This library uses the Analysis library to figure out offsets for
+// variables in the method tables...
+//
+// Note that this file uses an unusual technique of outputting all the bytecode
+// to a vector of unsigned char's, then copies the vector to an ostream.  The
+// reason for this is that we must do "seeking" in the stream to do back-
+// patching, and some very important ostreams that we want to support (like
+// pipes) do not support seeking.  :( :( :(
+//
+// The choice of the vector data structure is influenced by the extremely fast
+// "append" speed, plus the free "seek"/replace in the middle of the stream.
+//
+// Note that the performance of this library is not terribly important, because
+// it shouldn't be used by JIT type applications... so it is not a huge focus
+// at least.  :)
+//
+//===----------------------------------------------------------------------===//
+
+#include "WriterInternals.h"
+#include "llvm/Module.h"
+#include "llvm/Method.h"
+#include "llvm/BasicBlock.h"
+#include "llvm/ConstPoolVals.h"
+#include "llvm/SymbolTable.h"
+#include "llvm/DerivedTypes.h"
+#include <string.h>
+#include <algorithm>
+
+BytecodeWriter::BytecodeWriter(vector<unsigned char> &o, const Module *M) 
+  : Out(o), Table(M, false) {
+
+  outputSignature();
+
+  // Emit the top level CLASS block.
+  BytecodeBlock ModuleBlock(BytecodeFormat::Module, Out);
+
+  // Output largest ID of first "primitive" type:
+  output_vbr((unsigned)Type::FirstDerivedTyID, Out);
+  align32(Out);
+
+  // Do the whole module now!
+  processModule(M);
+
+  // If needed, output the symbol table for the class...
+  if (M->hasSymbolTable())
+    outputSymbolTable(*M->getSymbolTable());
+}
+
+// TODO: REMOVE
+#include "llvm/Assembly/Writer.h"
+
+bool BytecodeWriter::processConstPool(const ConstantPool &CP, bool isMethod) {
+  BytecodeBlock *CPool = new BytecodeBlock(BytecodeFormat::ConstantPool, Out);
+
+  unsigned NumPlanes = Table.getNumPlanes();
+
+  for (unsigned pno = 0; pno < NumPlanes; pno++) {
+    const vector<const Value*> &Plane = Table.getPlane(pno);
+    if (Plane.empty()) continue;          // Skip empty type planes...
+
+    unsigned ValNo = 0;   // Don't reemit module constants
+    if (isMethod) ValNo = Table.getModuleLevel(pno);
+    
+    unsigned NumConstants = 0;
+    for (unsigned vn = ValNo; vn < Plane.size(); vn++)
+      if (Plane[vn]->getValueType() == Value::ConstantVal)
+	NumConstants++;
+
+    if (NumConstants == 0) continue;  // Skip empty type planes...
+
+    // Output type header: [num entries][type id number]
+    //
+    output_vbr(NumConstants, Out);
+
+    // Output the Type ID Number...
+    int Slot = Table.getValSlot(Plane.front()->getType());
+    assert (Slot != -1 && "Type in constant pool but not in method!!");
+    output_vbr((unsigned)Slot, Out);
+
+    //cerr << "NC: " << NumConstants << " Slot = " << hex << Slot << endl;
+
+    for (; ValNo < Plane.size(); ValNo++) {
+      const Value *V = Plane[ValNo];
+      if (V->getValueType() == Value::ConstantVal) {
+	//cerr << "Serializing value: <" << V->getType() << ">: " 
+	//     << ((const ConstPoolVal*)V)->getStrValue() << ":" 
+	//     << Out.size() << "\n";
+	outputConstant((const ConstPoolVal*)V);
+      }
+    }
+  }
+
+  delete CPool;  // End bytecode block section!
+
+  if (!isMethod) { // The ModuleInfoBlock follows directly after the c-pool
+    assert(CP.getParent()->getValueType() == Value::ModuleVal);
+    outputModuleInfoBlock((const Module*)CP.getParent());
+  }
+
+  return false;
+}
+
+void BytecodeWriter::outputModuleInfoBlock(const Module *M) {
+  BytecodeBlock ModuleInfoBlock(BytecodeFormat::ModuleGlobalInfo, Out);
+  
+  // Output the types of the methods in this class
+  Module::MethodListType::const_iterator I = M->getMethodList().begin();
+  while (I != M->getMethodList().end()) {
+    int Slot = Table.getValSlot((*I)->getType());
+    assert(Slot != -1 && "Module const pool is broken!");
+    assert(Slot >= Type::FirstDerivedTyID && "Derived type not in range!");
+    output_vbr((unsigned)Slot, Out);
+    I++;
+  }
+  output_vbr((unsigned)Table.getValSlot(Type::VoidTy), Out);
+  align32(Out);
+}
+
+bool BytecodeWriter::processMethod(const Method *M) {
+  BytecodeBlock MethodBlock(BytecodeFormat::Method, Out);
+
+  Table.incorporateMethod(M);
+
+  if (ModuleAnalyzer::processMethod(M)) return true;
+  
+  // If needed, output the symbol table for the method...
+  if (M->hasSymbolTable())
+    outputSymbolTable(*M->getSymbolTable());
+
+  Table.purgeMethod();
+  return false;
+}
+
+
+bool BytecodeWriter::processBasicBlock(const BasicBlock *BB) {
+  BytecodeBlock MethodBlock(BytecodeFormat::BasicBlock, Out);
+  return ModuleAnalyzer::processBasicBlock(BB);
+}
+
+void BytecodeWriter::outputSymbolTable(const SymbolTable &MST) {
+  BytecodeBlock MethodBlock(BytecodeFormat::SymbolTable, Out);
+
+  for (SymbolTable::const_iterator TI = MST.begin(); TI != MST.end(); TI++) {
+    SymbolTable::type_const_iterator I = MST.type_begin(TI->first);
+    SymbolTable::type_const_iterator End = MST.type_end(TI->first);
+    int Slot;
+    
+    if (I == End) continue;  // Don't mess with an absent type...
+
+    // Symtab block header: [num entries][type id number]
+    output_vbr(MST.type_size(TI->first), Out);
+
+    Slot = Table.getValSlot(TI->first);
+    assert(Slot != -1 && "Type in symtab, but not in table!");
+    output_vbr((unsigned)Slot, Out);
+
+    for (; I != End; I++) {
+      // Symtab entry: [def slot #][name]
+      Slot = Table.getValSlot(I->second);
+      assert (Slot != -1 && "Value in symtab but not in method!!");
+      output_vbr((unsigned)Slot, Out);
+      output(I->first, Out, false); // Don't force alignment...
+    }
+  }
+}
+
+void WriteBytecodeToFile(const Module *C, ostream &Out) {
+  assert(C && "You can't write a null class!!");
+
+  vector<unsigned char> Buffer;
+
+  // This object populates buffer for us...
+  BytecodeWriter BCW(Buffer, C);
+
+  // Okay, write the vector out to the ostream now...
+  Out.write(&Buffer[0], Buffer.size());
+  Out.flush();
+}