Initial checkin of global var support code

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4904 91177308-0d34-0410-b5e6-96231b3b80d8

tools/jello/GlobalVars.cpp

@@ -0,0 +1,90 @@
+//===-- GlobalVars.cpp - Code to emit global variables to memory ----------===//
+//
+// This file contains the code to generate global variables to memory.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Module.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Constants.h"
+#include "llvm/Target/TargetMachine.h"
+#include "VM.h"
+
+/// EmitGlobals - Emit all of the global variables to memory, storing their
+/// addresses into GlobalAddress.  This must make sure to copy the contents of
+/// their initializers into the memory.
+///
+void VM::emitGlobals() {
+  const TargetData &TD = TM.getTargetData();
+  
+  // Loop over all of the global variables in the program, allocating the memory
+  // to hold them.
+  for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
+    if (!I->isExternal()) {
+      // Get the type of the global...
+      const Type *Ty = I->getType()->getElementType();
+      
+      // Allocate some memory for it!
+      GlobalAddress[I] = new char[TD.getTypeSize(Ty)];
+      
+      std::cerr << "Allocated global '" << I->getName()
+                << "' to addr 0x" << std::hex << GlobalAddress[I] << std::dec
+                << "\n";
+    } else {
+      assert(0 && "References to external globals not handled yet!");
+    }
+  
+  // Now that all of the globals are set up in memory, loop through them all and
+  // initialize their contents.
+  for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
+    if (!I->isExternal())
+      emitConstantToMemory(I->getInitializer(), GlobalAddress[I]);
+}
+
+/// emitConstantToMemory - Use the specified LLVM constant to initialize the
+/// specified region of memory.
+///
+void VM::emitConstantToMemory(Constant *Init, void *Addr) {
+  const TargetData &TD = TM.getTargetData();
+  if (ConstantIntegral *CI = dyn_cast<ConstantIntegral>(Init)) {
+    switch (CI->getType()->getPrimitiveID()) {
+    case Type::BoolTyID:
+      *(char*)Addr = cast<ConstantBool>(CI)->getValue();
+      return;
+    case Type::UByteTyID:
+      *(unsigned char*)Addr = cast<ConstantUInt>(CI)->getValue();
+      return;
+    case Type::SByteTyID:
+      *(  signed char*)Addr = cast<ConstantSInt>(CI)->getValue();
+      return;
+    case Type::UShortTyID:
+      *(unsigned short*)Addr = cast<ConstantUInt>(CI)->getValue();
+      return;
+    case Type::ShortTyID:
+      *(  signed short*)Addr = cast<ConstantSInt>(CI)->getValue();
+      return;
+    case Type::UIntTyID:
+      *(unsigned int*)Addr = cast<ConstantUInt>(CI)->getValue();
+      return;
+    case Type::IntTyID:
+      *(  signed int*)Addr = cast<ConstantSInt>(CI)->getValue();
+      return;
+    case Type::ULongTyID:
+      *(uint64_t*)Addr = cast<ConstantUInt>(CI)->getValue();
+      return;
+    case Type::LongTyID:
+      *(int64_t*)Addr = cast<ConstantSInt>(CI)->getValue();
+      return;
+    default: break;
+    }
+  } else if (ConstantArray *CA = dyn_cast<ConstantArray>(Init)) {
+    unsigned ElementSize = TD.getTypeSize(CA->getType()->getElementType());
+    for (unsigned i = 0, e = CA->getType()->getNumElements(); i != e; ++i) {
+      emitConstantToMemory(cast<Constant>(CA->getOperand(i)), Addr);
+      Addr = (char*)Addr+ElementSize;
+    }
+    return;
+  }
+
+  assert(0 && "Don't know how to emit this constant to memory!");
+}