* Feel free to change this code in any way that you find useful, * or to ignore it completely and roll your own code generator from * scratch. *
* This code assumes that your top-level AST node is called * Program. You may need to change this to match your own AST * hierarchy. Usage: * *
* CodeGenerator cg = new CodeGenerator("file.ic", program);
* cg.generate();
*
*/
public class CodeGenerator64 {
/** The name of the assembly file being generated */
protected final String asmFile;
/** The writer used to print the assembly file */
protected final PrintWriter out;
/** The program being translated into assembly */
protected final Program program;
/**
* Given a file name "file.ic" and a program AST, construct a
* code generator to print "file.s", the assembly code version
* of the program.
*/
public CodeGenerator64(String icFileName, Program program) throws IOException {
asmFile = icFileName.substring(0, icFileName.indexOf('.')) + ".s";
out = new PrintWriter(new FileWriter(asmFile));
this.program = program;
}
/**
* The main method to call when you wish to perform the
* translation.
*/
public void generate() {
out.println("# File " + asmFile);
out.println();
out.println();
generateVTables();
generateCode();
generateErrorHandlers();
// TODO: Provide the real information for main.
String classForMain = "Simple";
int sizeOfMainObject = 8;
int offsetOfMainInDV = 0;
generateMain(classForMain, sizeOfMainObject, offsetOfMainInDV);
generateStringConstants();
out.close();
}
/**
* Print the VTable for all the classes. You'll need to change this.
*
*/
protected void generateVTables() {
// TODO: You must implement this method
out.println("# ----------------------------");
out.println("# VTables");
out.println();
out.println(".data");
out.println(".align 8");
out.println();
out.println("_Simple_DV:");
out.println(" .quad _Simple_main");
out.println("");
out.println("");
out.println("");
}
/**
* Generate Simple.main method. You'll need to change this.
*/
protected void generateCode() {
// TODO: You must implement this method
out.println("# ----------------------------");
out.println("# Code. Just the Simple main method for now...");
out.println("");
out.println(".text");
out.println(".align 8");
out.println("_Simple_main:");
out.println("");
out.println(" # prologue");
out.println(" pushq %rbp ");
out.println(" movq %rsp, %rbp ");
out.println(" subq $8, %rsp ");
out.println("");
out.println(" # store 1234 into a local variable.");
out.println(" movq $1234, %rcx ");
out.println(" movq %rcx, -8(%rbp)");
out.println("");
out.println(" # print that local var...");
out.println(" movq -8(%rbp), %rdi");
out.println(" call __LIB_printi");
out.println("");
out.println(" # ... and a new line");
out.printf (" movq %s(%%rip), %%rdi\n",
labelForStringConstant("\na string \n containing \t\t quotes and escape characters: \"moo\"\n"));
out.println(" call __LIB_println");
out.println(" ");
out.println(" # epilogue");
out.println(" movq %rbp, %rsp ");
out.println(" popq %rbp ");
out.println(" ret ");
out.println("");
out.println("");
out.println("");
}
/**
* Print out the assembly code to print run-time errors and
* exit gracefully. You should jump to these labels on
* run-time check failure. You should not need to change this
* method.
*/
protected void generateErrorHandlers() {
out.println("# ----------------------------");
out.println("# Error handling. Jump to these procedures when a run-time check fails.");
out.println("");
out.println(".data");
out.println(".align 8");
out.println("");
out.println(".long 23");
out.println(" strNullPtrErrorChars: .ascii \"Null pointer violation.\"");
out.println("strNullPtrError: .quad strNullPtrErrorChars");
out.println("");
out.println(".long 23");
out.println(" strArrayBoundsErrorChars: .ascii \"Array bounds violation.\"");
out.println("strArrayBoundsError: .quad strArrayBoundsErrorChars");
out.println("");
out.println(".long 21");
out.println(" strArraySizeErrorChars: .ascii \"Array size violation.\"");
out.println("strArraySizeError: .quad strArraySizeErrorChars");
out.println("");
out.println(".text");
out.println(".align 8");
out.println("labelNullPtrError:");
out.println(" movq strNullPtrError(%rip), %rdi");
out.println(" call __LIB_println");
out.println(" movq $1, %rdi");
out.println(" call __LIB_exit");
out.println("");
out.println(".align 4");
out.println("labelArrayBoundsError:");
out.println(" movq strArrayBoundsError(%rip), %rdi");
out.println(" call __LIB_println");
out.println(" movq $1, %rdi");
out.println(" call __LIB_exit");
out.println("");
out.println(".align 4");
out.println("labelArraySizeError:");
out.println(" movq strArraySizeError(%rip), %rdi");
out.println(" call __LIB_println");
out.println(" movq $1, %rdi");
out.println(" call __LIB_exit");
out.println("");
out.println("");
out.println("");
}
/**
* Generate the __ic_main stub that creates and calls main on
* the right object. You should not need to change this
* method.
* @param className name of the class containing main
* @param objectSize size of objects of that class
* @param indexOfMainInVTable index on that class's vtable for main
*/
protected void generateMain(String className, int objectSize, int indexOfMainInVTable) {
out.println("# The main entry point. Allocate object and invoke main on it.");
out.println("");
out.println(".text");
out.println(".align 8");
out.println(".globl __ic_main");
out.println("__ic_main:");
out.println(" pushq %rbp # prologue");
out.println(" movq %rsp,%rbp ");
out.println(" pushq %rdi # o.main(args) -> push args");
out.println("");
out.printf (" movq $%-4d, %%rdi # o = new %s\n",
objectSize, className);
out.println(" call __LIB_allocateObject ");
out.printf (" leaq _%s_DV(%%rip), %%rdi \n",
className);
out.println(" movq %rdi, (%rax)");
out.println(" pushq %rax # o.main(args) -> push o");
out.println(" movq (%rax), %rax ");
out.printf (" call *%d(%%rax) # main is at offset %d in vtable\n",
indexOfMainInVTable * 4, indexOfMainInVTable);
out.println(" addq $16, %rsp ");
out.println(" movq $0, %rax # __ic_main always returns 0");
out.println("");
out.println(" movq %rbp,%rsp # epilogue");
out.println(" popq %rbp ");
out.println(" ret ");
out.println("");
out.println("");
out.println("");
}
/********************** String Constants *********************/
/** A map from string constant to the assembly code label in
* the data segment where that constant is stored. See the
* labelForStringConstant method.
*/
protected final HashMap