cbc/net/loveruby/cflat/sysdep/x86/CodeGenerator.java

1123 lines
32 KiB
Java

package net.loveruby.cflat.sysdep.x86;
import net.loveruby.cflat.sysdep.CodeGeneratorOptions;
import net.loveruby.cflat.ir.*;
import net.loveruby.cflat.entity.*;
import net.loveruby.cflat.asm.*;
import net.loveruby.cflat.ast.Location;
import net.loveruby.cflat.utils.AsmUtils;
import net.loveruby.cflat.utils.ListUtils;
import net.loveruby.cflat.utils.ErrorHandler;
import java.util.*;
public class CodeGenerator implements net.loveruby.cflat.sysdep.CodeGenerator,
IRVisitor<Void,Void>, ELFConstants {
// #@@range/ctor{
final CodeGeneratorOptions options;
final Type naturalType;
final ErrorHandler errorHandler;
public CodeGenerator(CodeGeneratorOptions options,
Type naturalType, ErrorHandler errorHandler) {
this.options = options;
this.naturalType = naturalType;
this.errorHandler = errorHandler;
}
// #@@}
/** Compiles IR and generates assembly code. */
// #@@range/generate{
public AssemblyCode generate(IR ir) {
locateSymbols(ir);
return generateAssemblyCode(ir);
}
// #@@}
static final String LABEL_SYMBOL_BASE = ".L";
static final String CONST_SYMBOL_BASE = ".LC";
//
// locateSymbols
//
// #@@range/locateSymbols{
private void locateSymbols(IR ir) {
SymbolTable constSymbols = new SymbolTable(CONST_SYMBOL_BASE);
for (ConstantEntry ent : ir.constantTable().entries()) {
locateStringLiteral(ent, constSymbols);
}
for (Variable var : ir.allGlobalVariables()) {
locateGlobalVariable(var);
}
for (Function func : ir.allFunctions()) {
locateFunction(func);
}
}
// #@@}
// #@@range/locateStringLiteral{
private void locateStringLiteral(ConstantEntry ent, SymbolTable syms) {
ent.setSymbol(syms.newSymbol());
if (options.isPositionIndependent()) {
Symbol offset = localGOTSymbol(ent.symbol());
ent.setMemref(mem(offset, GOTBaseReg()));
}
else {
ent.setMemref(mem(ent.symbol()));
ent.setAddress(imm(ent.symbol()));
}
}
// #@@}
// #@@range/locateGlobalVariable{
private void locateGlobalVariable(Entity ent) {
Symbol sym = symbol(ent.symbolString(), ent.isPrivate());
if (options.isPositionIndependent()) {
if (ent.isPrivate() || optimizeGvarAccess(ent)) {
ent.setMemref(mem(localGOTSymbol(sym), GOTBaseReg()));
}
else {
ent.setAddress(mem(globalGOTSymbol(sym), GOTBaseReg()));
}
}
else {
ent.setMemref(mem(sym));
ent.setAddress(imm(sym));
}
}
// #@@}
// #@@range/locateFunction{
private void locateFunction(Function func) {
func.setCallingSymbol(callingSymbol(func));
locateGlobalVariable(func);
}
// #@@}
// #@@range/symbol{
private Symbol symbol(String sym, boolean isPrivate) {
return isPrivate ? privateSymbol(sym) : globalSymbol(sym);
}
// #@@}
// #@@range/globalSymbol{
private Symbol globalSymbol(String sym) {
return new NamedSymbol(sym);
}
// #@@}
// #@@range/privateSymbol{
private Symbol privateSymbol(String sym) {
return new NamedSymbol(sym);
}
// #@@}
// #@@range/callingSymbol{
private Symbol callingSymbol(Function func) {
if (func.isPrivate()) {
return privateSymbol(func.symbolString());
}
else {
Symbol sym = globalSymbol(func.symbolString());
return shouldUsePLT(func) ? PLTSymbol(sym) : sym;
}
}
// #@@}
// #@@range/shouldUsePLT{
private boolean shouldUsePLT(Entity ent) {
return options.isPositionIndependent() && !optimizeGvarAccess(ent);
}
// #@@}
// #@@range/optimizeGvarAccess{
private boolean optimizeGvarAccess(Entity ent) {
return options.isPIERequired() && ent.isDefined();
}
// #@@}
//
// generateAssemblyCode
//
// #@@range/generateAssemblyCode{
private AssemblyCode generateAssemblyCode(IR ir) {
AssemblyCode file = newAssemblyCode();
file._file(ir.fileName());
if (ir.isGlobalVariableDefined()) {
generateDataSection(file, ir.definedGlobalVariables());
}
if (ir.isStringLiteralDefined()) {
generateReadOnlyDataSection(file, ir.constantTable());
}
if (ir.isFunctionDefined()) {
generateTextSection(file, ir.definedFunctions());
}
if (ir.isCommonSymbolDefined()) {
generateCommonSymbols(file, ir.definedCommonSymbols());
}
if (options.isPositionIndependent()) {
PICThunk(file, GOTBaseReg());
}
return file;
}
// #@@}
// #@@range/newAssemblyCode{
private AssemblyCode newAssemblyCode() {
return new AssemblyCode(
naturalType, STACK_WORD_SIZE,
new SymbolTable(LABEL_SYMBOL_BASE),
options.isVerboseAsm());
}
// #@@}
/** Generates initialized entries */
// #@@range/generateDataSection{
private void generateDataSection(AssemblyCode file,
List<DefinedVariable> gvars) {
file._data();
for (DefinedVariable var : gvars) {
Symbol sym = globalSymbol(var.symbolString());
if (!var.isPrivate()) {
file._globl(sym);
}
file._align(var.alignment());
file._type(sym, "@object");
file._size(sym, var.allocSize());
file.label(sym);
generateImmediate(file, var.type().allocSize(), var.ir());
}
}
// #@@}
/** Generates immediate values for .data section */
// #@@range/generateImmediate{
private void generateImmediate(AssemblyCode file, long size, Expr node) {
if (node instanceof Int) {
Int expr = (Int)node;
switch ((int)size) {
case 1: file._byte(expr.value()); break;
case 2: file._value(expr.value()); break;
case 4: file._long(expr.value()); break;
case 8: file._quad(expr.value()); break;
default:
throw new Error("entry size must be 1,2,4,8");
}
}
else if (node instanceof Str) {
Str expr = (Str)node;
switch ((int)size) {
case 4: file._long(expr.symbol()); break;
case 8: file._quad(expr.symbol()); break;
default:
throw new Error("pointer size must be 4,8");
}
}
else {
throw new Error("unknown literal node type" + node.getClass());
}
}
// #@@}
/** Generates .rodata entries (constant strings) */
// #@@range/generateReadOnlyDataSection{
private void generateReadOnlyDataSection(AssemblyCode file,
ConstantTable constants) {
file._section(".rodata");
for (ConstantEntry ent : constants) {
file.label(ent.symbol());
file._string(ent.value());
}
}
// #@@}
// #@@range/generateTextSection{
private void generateTextSection(AssemblyCode file,
List<DefinedFunction> functions) {
file._text();
for (DefinedFunction func : functions) {
Symbol sym = globalSymbol(func.name());
if (! func.isPrivate()) {
file._globl(sym);
}
file._type(sym, "@function");
file.label(sym);
compileFunctionBody(file, func);
file._size(sym, ".-" + sym.toSource());
}
}
// #@@}
/** Generates BSS entries */
// #@@range/generateCommonSymbols{
private void generateCommonSymbols(AssemblyCode file,
List<DefinedVariable> variables) {
for (DefinedVariable var : variables) {
Symbol sym = globalSymbol(var.symbolString());
if (var.isPrivate()) {
file._local(sym);
}
file._comm(sym, var.allocSize(), var.alignment());
}
}
// #@@}
//
// PIC/PIE related constants and codes
//
// #@@range/pic_methods{
static private final Symbol GOT =
new NamedSymbol("_GLOBAL_OFFSET_TABLE_");
private void loadGOTBaseAddress(AssemblyCode file, Register reg) {
file.call(PICThunkSymbol(reg));
file.add(imm(GOT), reg);
}
private Register GOTBaseReg() {
return bx();
}
// #@@}
// #@@range/pic_symbols{
private Symbol globalGOTSymbol(Symbol base) {
return new SuffixedSymbol(base, "@GOT");
}
private Symbol localGOTSymbol(Symbol base) {
return new SuffixedSymbol(base, "@GOTOFF");
}
private Symbol PLTSymbol(Symbol base) {
return new SuffixedSymbol(base, "@PLT");
}
// #@@}
// #@@range/pic_thunk_helper{
private Symbol PICThunkSymbol(Register reg) {
return new NamedSymbol("__i686.get_pc_thunk." + reg.baseName());
}
static private final String
PICThunkSectionFlags = SectionFlag_allocatable
+ SectionFlag_executable
+ SectionFlag_sectiongroup;
// #@@}
/**
* Output PIC thunk.
* ELF section declaration format is:
*
* .section NAME, FLAGS, TYPE, flag_arguments
*
* FLAGS, TYPE, flag_arguments are optional.
* For "M" flag (a member of a section group),
* following format is used:
*
* .section NAME, "...M", TYPE, section_group_name, linkage
*/
// #@@range/PICThunk{
private void PICThunk(AssemblyCode file, Register reg) {
Symbol sym = PICThunkSymbol(reg);
file._section(".text" + "." + sym.toSource(),
"\"" + PICThunkSectionFlags + "\"",
SectionType_bits, // This section contains data
sym.toSource(), // The name of section group
Linkage_linkonce); // Only 1 copy should be generated
file._globl(sym);
file._hidden(sym);
file._type(sym, SymbolType_function);
file.label(sym);
file.mov(mem(sp()), reg); // fetch saved EIP to the GOT base register
file.ret();
}
// #@@}
//
// Compile Function
//
/* Standard IA-32 stack frame layout
*
* ======================= esp #3 (stack top just before function call)
* next arg 1
* ---------------------
* next arg 2
* ---------------------
* next arg 3
* --------------------- esp #2 (stack top after alloca call)
* alloca area
* --------------------- esp #1 (stack top just after prelude)
* temporary
* variables...
* --------------------- -16(%ebp)
* lvar 3
* --------------------- -12(%ebp)
* lvar 2
* --------------------- -8(%ebp)
* lvar 1
* --------------------- -4(%ebp)
* callee-saved register
* ======================= 0(%ebp)
* saved ebp
* --------------------- 4(%ebp)
* return address
* --------------------- 8(%ebp)
* arg 1
* --------------------- 12(%ebp)
* arg 2
* --------------------- 16(%ebp)
* arg 3
* ...
* ...
* ======================= stack bottom
*/
// #@@range/stackParams{
static final private long STACK_WORD_SIZE = 4;
// #@@}
// #@@range/alignStack{
private long alignStack(long size) {
return AsmUtils.align(size, STACK_WORD_SIZE);
}
// #@@}
// #@@range/stackSizeFromWordNum{
private long stackSizeFromWordNum(long numWords) {
return numWords * STACK_WORD_SIZE;
}
// #@@}
// #@@range/StackFrameInfo{
class StackFrameInfo {
List<Register> saveRegs;
long lvarSize;
long tempSize;
long saveRegsSize() { return saveRegs.size() * STACK_WORD_SIZE; }
long lvarOffset() { return saveRegsSize(); }
long tempOffset() { return saveRegsSize() + lvarSize; }
long frameSize() { return saveRegsSize() + lvarSize + tempSize; }
}
// #@@}
// #@@range/compileFunctionBody{
private void compileFunctionBody(AssemblyCode file, DefinedFunction func) {
StackFrameInfo frame = new StackFrameInfo();
// #@@range/cfb_locate{
locateParameters(func.parameters());
frame.lvarSize = locateLocalVariables(func.lvarScope());
// #@@}
// #@@range/cfb_offset{
AssemblyCode body = optimize(compileStmts(func));
frame.saveRegs = usedCalleeSavedRegisters(body);
frame.tempSize = body.virtualStack.maxSize();
fixLocalVariableOffsets(func.lvarScope(), frame.lvarOffset());
fixTempVariableOffsets(body, frame.tempOffset());
// #@@}
if (options.isVerboseAsm()) {
printStackFrameLayout(file, frame, func.localVariables());
}
// #@@range/cfb_gen{
generateFunctionBody(file, body, frame);
// #@@}
}
// #@@}
// #@@range/optimize{
private AssemblyCode optimize(AssemblyCode body) {
if (options.optimizeLevel() < 1) {
return body;
}
body.apply(PeepholeOptimizer.defaultSet());
body.reduceLabels();
return body;
}
// #@@}
private void printStackFrameLayout(AssemblyCode file,
StackFrameInfo frame, List<DefinedVariable> lvars) {
List<MemInfo> vars = new ArrayList<MemInfo>();
for (DefinedVariable var : lvars) {
vars.add(new MemInfo(var.memref(), var.name()));
}
vars.add(new MemInfo(mem(0, bp()), "return address"));
vars.add(new MemInfo(mem(4, bp()), "saved %ebp"));
if (frame.saveRegsSize() > 0) {
vars.add(new MemInfo(mem(-frame.saveRegsSize(), bp()),
"saved callee-saved registers (" + frame.saveRegsSize() + " bytes)"));
}
if (frame.tempSize > 0) {
vars.add(new MemInfo(mem(-frame.frameSize(), bp()),
"tmp variables (" + frame.tempSize + " bytes)"));
}
Collections.sort(vars, new Comparator<MemInfo>() {
public int compare(MemInfo x, MemInfo y) {
return x.mem.compareTo(y.mem);
}
});
file.comment("---- Stack Frame Layout -----------");
for (MemInfo info : vars) {
file.comment(info.mem.toString() + ": " + info.name);
}
file.comment("-----------------------------------");
}
class MemInfo {
MemoryReference mem;
String name;
MemInfo(MemoryReference mem, String name) {
this.mem = mem;
this.name = name;
}
}
// #@@range/compileStmts{
private AssemblyCode as;
private Label epilogue;
private AssemblyCode compileStmts(DefinedFunction func) {
as = newAssemblyCode();
epilogue = new Label();
for (Stmt s : func.ir()) {
compileStmt(s);
}
as.label(epilogue);
return as;
}
// #@@}
// does NOT include BP
// #@@range/usedCalleeSavedRegisters{
private List<Register> usedCalleeSavedRegisters(AssemblyCode body) {
List<Register> result = new ArrayList<Register>();
for (Register reg : calleeSavedRegisters()) {
if (body.doesUses(reg)) {
result.add(reg);
}
}
result.remove(bp());
return result;
}
// #@@}
static final RegisterClass[] CALLEE_SAVED_REGISTERS = {
RegisterClass.BX, RegisterClass.BP,
RegisterClass.SI, RegisterClass.DI
};
private List<Register> calleeSavedRegistersCache = null;
private List<Register> calleeSavedRegisters() {
if (calleeSavedRegistersCache == null) {
List<Register> regs = new ArrayList<Register>();
for (RegisterClass c : CALLEE_SAVED_REGISTERS) {
regs.add(new Register(c, naturalType));
}
calleeSavedRegistersCache = regs;
}
return calleeSavedRegistersCache;
}
// #@@range/generateFunctionBody{
private void generateFunctionBody(AssemblyCode file,
AssemblyCode body, StackFrameInfo frame) {
file.virtualStack.reset();
prologue(file, frame.saveRegs, frame.frameSize());
if (options.isPositionIndependent() && body.doesUses(GOTBaseReg())) {
loadGOTBaseAddress(file, GOTBaseReg());
}
file.addAll(body.assemblies());
epilogue(file, frame.saveRegs);
file.virtualStack.fixOffset(0);
}
// #@@}
// #@@range/prologue{
private void prologue(AssemblyCode file,
List<Register> saveRegs, long frameSize) {
file.push(bp());
file.mov(sp(), bp());
for (Register reg : saveRegs) {
file.virtualPush(reg);
}
extendStack(file, frameSize);
}
// #@@}
// #@@range/epilogue{
private void epilogue(AssemblyCode file, List<Register> savedRegs) {
for (Register reg : ListUtils.reverse(savedRegs)) {
file.virtualPop(reg);
}
file.mov(bp(), sp());
file.pop(bp());
file.ret();
}
// #@@}
// #@@range/locateParameters{
static final private long PARAM_START_WORD = 2;
// return addr and saved bp
private void locateParameters(List<Parameter> params) {
long numWords = PARAM_START_WORD;
for (Parameter var : params) {
var.setMemref(mem(stackSizeFromWordNum(numWords), bp()));
numWords++;
}
}
// #@@}
/**
* Allocates addresses of local variables, but offset is still
* not determined, assign unfixed IndirectMemoryReference.
*/
// #@@range/locateLocalVariables{
private long locateLocalVariables(LocalScope scope) {
return locateLocalVariables(scope, 0);
}
private long locateLocalVariables(LocalScope scope, long parentStackLen) {
// #@@range/locateLocalVariables_loc{
long len = parentStackLen;
for (DefinedVariable var : scope.localVariables()) {
len = alignStack(len + var.allocSize());
var.setMemref(relocatableMem(-len, bp()));
}
// #@@}
// #@@range/locateLocalVariables_child{
long maxLen = len;
for (LocalScope s : scope.children()) {
long childLen = locateLocalVariables(s, len);
maxLen = Math.max(maxLen, childLen);
}
return maxLen;
// #@@}
}
// #@@}
// #@@range/relocatableMem{
private IndirectMemoryReference relocatableMem(long offset, Register base) {
return IndirectMemoryReference.relocatable(offset, base);
}
// #@@}
// #@@range/fixLocalVariableOffsets{
private void fixLocalVariableOffsets(LocalScope scope, long len) {
for (DefinedVariable var : scope.allLocalVariables()) {
var.memref().fixOffset(-len);
}
}
// #@@}
// #@@range/fixTempVariableOffsets{
private void fixTempVariableOffsets(AssemblyCode asm, long len) {
asm.virtualStack.fixOffset(-len);
}
// #@@}
// #@@range/extendStack{
private void extendStack(AssemblyCode file, long len) {
if (len > 0) {
file.sub(imm(len), sp());
}
}
// #@@}
// #@@range/rewindStack{
private void rewindStack(AssemblyCode file, long len) {
if (len > 0) {
file.add(imm(len), sp());
}
}
// #@@}
/**
* Implements cdecl function call:
* * All arguments are on stack.
* * Caller rewinds stack pointer.
*/
// #@@range/Call{
public Void visit(Call node) {
for (Expr arg : ListUtils.reverse(node.args())) {
compile(arg);
as.push(ax());
}
if (node.isStaticCall()) {
as.call(node.function().callingSymbol());
}
else {
compile(node.expr());
as.callAbsolute(ax());
}
// >4 bytes arguments are not supported.
rewindStack(as, stackSizeFromWordNum(node.numArgs()));
return null;
}
// #@@}
// #@@range/Return{
public Void visit(Return node) {
if (node.expr() != null) {
compile(node.expr());
}
as.jmp(epilogue);
return null;
}
// #@@}
//
// Statements
//
// #@@range/compileStmt{
private void compileStmt(Stmt stmt) {
if (options.isVerboseAsm()) {
if (stmt.location() != null) {
as.comment(stmt.location().numberedLine());
}
}
stmt.accept(this);
}
// #@@}
// #@@range/ExprStmt{
public Void visit(ExprStmt stmt) {
compile(stmt.expr());
return null;
}
// #@@}
// #@@range/LabelStmt{
public Void visit(LabelStmt node) {
as.label(node.label());
return null;
}
// #@@}
// #@@range/Jump{
public Void visit(Jump node) {
as.jmp(node.label());
return null;
}
// #@@}
// #@@range/CJump{
public Void visit(CJump node) {
compile(node.cond());
Type t = node.cond().type();
as.test(ax(t), ax(t));
as.jnz(node.thenLabel());
as.jmp(node.elseLabel());
return null;
}
// #@@}
public Void visit(Switch node) {
compile(node.cond());
Type t = node.cond().type();
for (Case c : node.cases()) {
as.mov(imm(c.value), cx());
as.cmp(cx(t), ax(t));
as.je(c.label);
}
as.jmp(node.defaultLabel());
return null;
}
//
// Expressions
//
// #@@range/compile{
private void compile(Expr n) {
if (options.isVerboseAsm()) {
as.comment(n.getClass().getSimpleName() + " {");
as.indentComment();
}
n.accept(this);
if (options.isVerboseAsm()) {
as.unindentComment();
as.comment("}");
}
}
// #@@}
// #@@range/Bin{
public Void visit(Bin node) {
// #@@range/Bin_init{
Op op = node.op();
Type t = node.type();
// #@@}
if (node.right().isConstant() && !doesRequireRegisterOperand(op)) {
// #@@range/Bin_const{
compile(node.left());
compileBinaryOp(op, ax(t), node.right().asmValue());
// #@@}
}
else if (node.right().isConstant()) {
compile(node.left());
loadConstant(node.right(), cx());
compileBinaryOp(op, ax(t), cx(t));
}
else if (node.right().isVar()) {
compile(node.left());
loadVariable((Var)node.right(), cx(t));
compileBinaryOp(op, ax(t), cx(t));
}
else if (node.right().isAddr()) {
compile(node.left());
loadAddress(node.right().getEntityForce(), cx(t));
compileBinaryOp(op, ax(t), cx(t));
}
else if (node.left().isConstant()
|| node.left().isVar()
|| node.left().isAddr()) {
compile(node.right());
as.mov(ax(), cx());
compile(node.left());
compileBinaryOp(op, ax(t), cx(t));
}
else {
// #@@range/Bin_generic{
compile(node.right());
as.virtualPush(ax());
compile(node.left());
as.virtualPop(cx());
compileBinaryOp(op, ax(t), cx(t));
// #@@}
}
return null;
}
// #@@}
// #@@range/doesRequireRegisterOperand{
private boolean doesRequireRegisterOperand(Op op) {
switch (op) {
case S_DIV:
case U_DIV:
case S_MOD:
case U_MOD:
case BIT_LSHIFT:
case BIT_RSHIFT:
case ARITH_RSHIFT:
return true;
default:
return false;
}
}
// #@@}
// #@@range/compileBinaryOp_begin{
private void compileBinaryOp(Op op, Register left, Operand right) {
// #@@range/compileBinaryOp_arithops{
switch (op) {
case ADD:
as.add(right, left);
break;
case SUB:
as.sub(right, left);
break;
// #@@range/compileBinaryOp_begin}
case MUL:
as.imul(right, left);
break;
case S_DIV:
case S_MOD:
as.cltd();
as.idiv(cx(left.type));
if (op == Op.S_MOD) {
as.mov(dx(), left);
}
break;
case U_DIV:
case U_MOD:
as.mov(imm(0), dx());
as.div(cx(left.type));
if (op == Op.U_MOD) {
as.mov(dx(), left);
}
break;
// #@@}
// #@@range/compileBinaryOp_bitops{
case BIT_AND:
as.and(right, left);
break;
case BIT_OR:
as.or(right, left);
break;
case BIT_XOR:
as.xor(right, left);
break;
case BIT_LSHIFT:
as.sal(cl(), left);
break;
case BIT_RSHIFT:
as.shr(cl(), left);
break;
case ARITH_RSHIFT:
as.sar(cl(), left);
break;
// #@@}
// #@@range/compileBinaryOp_cmpops{
default:
// Comparison operators
as.cmp(right, ax(left.type));
switch (op) {
case EQ: as.sete (al()); break;
case NEQ: as.setne(al()); break;
case S_GT: as.setg (al()); break;
case S_GTEQ: as.setge(al()); break;
case S_LT: as.setl (al()); break;
case S_LTEQ: as.setle(al()); break;
case U_GT: as.seta (al()); break;
case U_GTEQ: as.setae(al()); break;
case U_LT: as.setb (al()); break;
case U_LTEQ: as.setbe(al()); break;
default:
throw new Error("unknown binary operator: " + op);
}
as.movzx(al(), left);
}
// #@@}
}
// #@@range/Uni{
public Void visit(Uni node) {
Type src = node.expr().type();
Type dest = node.type();
compile(node.expr());
switch (node.op()) {
case UMINUS:
as.neg(ax(src));
break;
case BIT_NOT:
as.not(ax(src));
break;
case NOT:
as.test(ax(src), ax(src));
as.sete(al());
as.movzx(al(), ax(dest));
break;
case S_CAST:
as.movsx(ax(src), ax(dest));
break;
case U_CAST:
as.movzx(ax(src), ax(dest));
break;
default:
throw new Error("unknown unary operator: " + node.op());
}
return null;
}
// #@@}
// #@@range/Var{
public Void visit(Var node) {
loadVariable(node, ax());
return null;
}
// #@@}
// #@@range/Int{
public Void visit(Int node) {
as.mov(imm(node.value()), ax());
return null;
}
// #@@}
// #@@range/Str{
public Void visit(Str node) {
loadConstant(node, ax());
return null;
}
// #@@}
//
// Assignable expressions
//
// #@@range/Assign{
public Void visit(Assign node) {
if (node.lhs().isAddr() && node.lhs().memref() != null) {
compile(node.rhs());
store(ax(node.lhs().type()), node.lhs().memref());
}
else if (node.rhs().isConstant()) {
compile(node.lhs());
as.mov(ax(), cx());
loadConstant(node.rhs(), ax());
store(ax(node.lhs().type()), mem(cx()));
}
else {
compile(node.rhs());
as.virtualPush(ax());
compile(node.lhs());
as.mov(ax(), cx());
as.virtualPop(ax());
store(ax(node.lhs().type()), mem(cx()));
}
return null;
}
// #@@}
// #@@range/Mem{
public Void visit(Mem node) {
compile(node.expr());
load(mem(ax()), ax(node.type()));
return null;
}
// #@@}
// #@@range/Addr{
public Void visit(Addr node) {
loadAddress(node.entity(), ax());
return null;
}
// #@@}
//
// Utilities
//
/**
* Loads constant value. You must check node by #isConstant
* before calling this method.
*/
// #@@range/loadConstant{
private void loadConstant(Expr node, Register reg) {
if (node.asmValue() != null) {
as.mov(node.asmValue(), reg);
}
else if (node.memref() != null) {
as.lea(node.memref(), reg);
}
else {
throw new Error("must not happen: constant has no asm value");
}
}
// #@@}
/** Loads variable content to the register. */
// #@@range/loadVariable{
private void loadVariable(Var var, Register dest) {
if (var.memref() == null) {
Register a = dest.forType(naturalType);
as.mov(var.address(), a);
load(mem(a), dest.forType(var.type()));
}
else {
load(var.memref(), dest.forType(var.type()));
}
}
// #@@}
/** Loads the address of the variable to the register. */
// #@@range/loadAddress{
private void loadAddress(Entity var, Register dest) {
if (var.address() != null) {
as.mov(var.address(), dest);
}
else {
as.lea(var.memref(), dest);
}
}
// #@@}
// #@@range/reg_dsls2{
private Register ax() { return ax(naturalType); }
private Register al() { return ax(Type.INT8); }
private Register bx() { return bx(naturalType); }
// #@@}
private Register cx() { return cx(naturalType); }
private Register cl() { return cx(Type.INT8); }
private Register dx() { return dx(naturalType); }
// #@@range/reg_dsls1{
private Register ax(Type t) {
return new Register(RegisterClass.AX, t);
}
private Register bx(Type t) {
return new Register(RegisterClass.BX, t);
}
// #@@}
private Register cx(Type t) {
return new Register(RegisterClass.CX, t);
}
private Register dx(Type t) {
return new Register(RegisterClass.DX, t);
}
private Register si() {
return new Register(RegisterClass.SI, naturalType);
}
private Register di() {
return new Register(RegisterClass.DI, naturalType);
}
private Register bp() {
return new Register(RegisterClass.BP, naturalType);
}
private Register sp() {
return new Register(RegisterClass.SP, naturalType);
}
// #@@range/mem{
private DirectMemoryReference mem(Symbol sym) {
return new DirectMemoryReference(sym);
}
private IndirectMemoryReference mem(Register reg) {
return new IndirectMemoryReference(0, reg);
}
private IndirectMemoryReference mem(long offset, Register reg) {
return new IndirectMemoryReference(offset, reg);
}
private IndirectMemoryReference mem(Symbol offset, Register reg) {
return new IndirectMemoryReference(offset, reg);
}
// #@@}
// #@@range/imm{
private ImmediateValue imm(long n) {
return new ImmediateValue(n);
}
private ImmediateValue imm(Symbol sym) {
return new ImmediateValue(sym);
}
private ImmediateValue imm(Literal lit) {
return new ImmediateValue(lit);
}
// #@@}
// #@@range/load{
private void load(MemoryReference mem, Register reg) {
as.mov(mem, reg);
}
// #@@}
// #@@range/store{
private void store(Register reg, MemoryReference mem) {
as.mov(reg, mem);
}
// #@@}
}