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ChocoPy/src/main/java/chocopy/pa3/CodeGenImpl.java

332 lines
14 KiB

package chocopy.pa3;
import chocopy.common.analysis.AbstractNodeAnalyzer;
import chocopy.common.analysis.SymbolTable;
import chocopy.common.analysis.types.FuncType;
import chocopy.common.analysis.types.Type;
import chocopy.common.astnodes.*;
import chocopy.common.codegen.*;
import java.util.List;
import chocopy.common.codegen.RiscVBackend.Register;
import static chocopy.common.codegen.RiscVBackend.Register.*;
/**
* This is where the main implementation of PA3 will live.
*
* <p>A large part of the functionality has already been implemented in the base class, CodeGenBase.
* Make sure to read through that class, since you will want to use many of its fields and utility
* methods in this class when emitting code.
*
* <p>Also read the PDF spec for details on what the base class does and what APIs it exposes for
* its sub-class (this one). Of particular importance is knowing what all the SymbolInfo classes
* contain.
*/
public class CodeGenImpl extends CodeGenBase {
/** A code generator emitting instructions to BACKEND. */
public CodeGenImpl(RiscVBackend backend) {
super(backend);
}
/** Operation on None. */
private final Label errorNone = new Label("error.None");
/** Division by zero. */
private final Label errorDiv = new Label("error.Div");
/** Index out of bounds. */
private final Label errorOob = new Label("error.OOB");
/**
* Emits the top level of the program.
*
* <p>This method is invoked exactly once, and is surrounded by some boilerplate code that: (1)
* initializes the heap before the top-level begins and (2) exits after the top-level ends.
*
* <p>You only need to generate code for statements.
*
* @param statements top level statements
*/
protected void emitTopLevel(List<Stmt> statements) {
StmtAnalyzer stmtAnalyzer = new StmtAnalyzer(null);
backend.emitADDI(
SP, SP, -2 * backend.getWordSize(), "Saved FP and saved RA (unused at top level).");
backend.emitSW(ZERO, SP, 0, "Top saved FP is 0.");
backend.emitSW(ZERO, SP, 4, "Top saved RA is 0.");
backend.emitADDI(FP, SP, 2 * backend.getWordSize(), "Set FP to previous SP.");
for (Stmt stmt : statements) {
stmt.dispatch(stmtAnalyzer);
}
backend.emitLI(A0, EXIT_ECALL, "Code for ecall: exit");
backend.emitEcall(null);
}
/**
* Emits the code for a function described by FUNCINFO.
*
* <p>This method is invoked once per function and method definition. At the code generation
* stage, nested functions are emitted as separate functions of their own. So if function `bar`
* is nested within function `foo`, you only emit `foo`'s code for `foo` and only emit `bar`'s
* code for `bar`.
*/
protected void emitUserDefinedFunction(FuncInfo funcInfo) {
backend.emitGlobalLabel(funcInfo.getCodeLabel());
StmtAnalyzer stmtAnalyzer = new StmtAnalyzer(funcInfo);
for (Stmt stmt : funcInfo.getStatements()) {
stmt.dispatch(stmtAnalyzer);
}
backend.emitMV(A0, ZERO, "Returning None implicitly");
backend.emitLocalLabel(stmtAnalyzer.epilogue, "Epilogue");
// FIXME: {... reset fp etc. ...}
backend.emitJR(RA, "Return to caller");
}
/** An analyzer that encapsulates code generation for statements. */
private class StmtAnalyzer extends AbstractNodeAnalyzer<Register> {
/*
* The symbol table has all the info you need to determine
* what a given identifier 'x' in the current scope is. You can
* use it as follows:
* SymbolInfo x = sym.get("x");
*
* A SymbolInfo can be one the following:
* - ClassInfo: a descriptor for classes
* - FuncInfo: a descriptor for functions/methods
* - AttrInfo: a descriptor for attributes
* - GlobalVarInfo: a descriptor for global variables
* - StackVarInfo: a descriptor for variables allocated on the stack,
* such as locals and parameters
*
* Since the input program is assumed to be semantically
* valid and well-typed at this stage, you can always assume that
* the symbol table contains valid information. For example, in
* an expression `foo()` you KNOW that sym.get("foo") will either be
* a FuncInfo or ClassInfo, but not any of the other infos
* and never null.
*
* The symbol table in funcInfo has already been populated in
* the base class: CodeGenBase. You do not need to add anything to
* the symbol table. Simply query it with an identifier name to
* get a descriptor for a function, class, variable, etc.
*
* The symbol table also maps nonlocal and global vars, so you
* only need to lookup one symbol table and it will fetch the
* appropriate info for the var that is currently in scope.
*/
/** Symbol table for my statements. */
private final SymbolTable<SymbolInfo> sym;
/** Label of code that exits from procedure. */
protected final Label epilogue;
/** The descriptor for the current function, or null at the top level. */
private final FuncInfo funcInfo;
private final String size_label;
private int sp_off, max_sp;
/** An analyzer for the function described by FUNCINFO0, which is null for the top level. */
StmtAnalyzer(FuncInfo funcInfo0) {
funcInfo = funcInfo0;
if (funcInfo == null) {
sym = globalSymbols;
sp_off = max_sp = 2;
size_label = "@..main.size";
} else {
sym = funcInfo.getSymbolTable();
sp_off = max_sp = funcInfo0.getLocals().size() + 2;
size_label = "@"+funcInfo0.getFuncName()+".size";
}
epilogue = generateLocalLabel();
}
public Register analyze(AssignStmt node) {
return null;
}
public Register analyze(BinaryExpr node) {
return null;
}
public Register analyze(BooleanLiteral node) {
return null;
}
public Register analyze(CallExpr node) {
SymbolInfo Ty = globalSymbols.get(node.function.name);
if(Ty instanceof ClassInfo){
//object create
ClassInfo cls = (ClassInfo) Ty;
/**
la a0, $DoublingVector$prototype # Load pointer to prototype of: DoublingVector
jal alloc # Allocate new object in A0
sw a0, -12(fp) # Push on stack slot 3
sw a0, -16(fp) # Push argument 0 from last.
addi sp, fp, -16 # Set SP to last argument.
lw a1, 8(a0) # Load address of object's dispatch table
lw a1, 0(a1) # Load address of method: DoublingVector.__init__
jalr a1 # Invoke method: DoublingVector.__init__
addi sp, fp, -@..main.size # Set SP to stack frame top.
lw a0, -12(fp) # Pop stack slot 3
*/
backend.emitLA(A0, cls.getPrototypeLabel(),
String.format("Load pointer to prototype of: %s", cls.getClassName()));
backend.emitJAL(objectAllocLabel, "Allocate new object in A0");
backend.emitSW(A0, FP, -sp_off*wordSize, String.format("Push on stack slot %d", sp_off));
if(sp_off>max_sp)
max_sp = sp_off;
sp_off++;
backend.emitSW(A0, FP, -sp_off*wordSize, "Push argument 0 from last.");
backend.emitADDI(SP, FP, sp_off, "Set SP to last argument.");
backend.emitLW(A1, A0, getDispatchTableOffset(), "Load address of object's dispatch table");
backend.emitLW(A1, A1, getMethodOffset(cls, "__init__"), String.format("Load address of method: %s.__init__", cls.getClassName()));
backend.emitJALR(A1, String.format("Invoke method: %s.__init", cls.getClassName()));
backend.emitADDI(SP, FP, "-"+size_label, "Set SP to stack frame top.");
sp_off--;
backend.emitLW(A0, FP, -sp_off*wordSize, String.format("Pop stack slot %d", sp_off));
} else {
//func call
}
return null;
}
public Register analyze(ExprStmt node) {
return null;
}
public Register analyze(ForStmt node) {
return null;
}
public Register analyze(Identifier node) {
return null;
}
public Register analyze(IfExpr node) {
return null;
}
public Register analyze(IfStmt node) {
return null;
}
public Register analyze(IndexExpr node) {
return null;
}
public Register analyze(IntegerLiteral node) {
return null;
}
public Register analyze(ListExpr node) {
return null;
}
public Register analyze(MemberExpr node) {
ClassInfo objectClass = (ClassInfo) globalSymbols.get(node.object.getInferredType().className());
Label label = generateLocalLabel();
Register obj = node.object.dispatch(this);
backend.emitBNEZ(obj, label, "Ensure not None");
backend.emitJ(errorNone, "Go to error handler");
backend.emitLocalLabel(label, "Not None");
backend.emitLW(A0, obj, getAttrOffset(objectClass, node.member.name),
String.format("Get attribute: %s.%s", objectClass.getClassName(), node.member.name));
return A0;
}
public Register analyze(MethodCallExpr node) {
Register obj = node.method.object.dispatch(this);
int n_args = node.args.size();
Label label = generateLocalLabel();
backend.emitBNEZ(obj, label, "Ensure not None");
backend.emitJ(errorNone, "Go to error handler");
backend.emitLocalLabel(label, "Not None");
if(sp_off>max_sp)
max_sp = sp_off;
sp_off += (n_args+1)*wordSize;
backend.emitSW(obj, FP, (n_args - sp_off) *wordSize, String.format("Push argument %d from last.", n_args));
for (int i = 0; i < n_args; ++i)
backend.emitSW(node.args.get(i).dispatch(this), FP, (n_args - i - 1 - sp_off) * wordSize,
String.format("Push argument %d from last.", n_args - i - 1));
backend.emitLW(A0, FP, (n_args- sp_off) * wordSize, String.format("Peek stack slot %d", sp_off - (n_args + 1)));
ClassInfo objectClass = (ClassInfo)sym.get(((Identifier)node.method.object).name);
backend.emitLW(A1, A0, getDispatchTableOffset(), "Load address of object's dispatch table");
backend.emitLW(A1, A1, getMethodOffset(objectClass, node.method.member.name),
String.format("Load address of method: %s.%s", objectClass.getClassName(), node.method.member.name));
backend.emitADDI(SP, FP, -sp_off * wordSize, "Set SP to last argument.");
backend.emitJALR(A1, String.format("Invoke method: %s.%s", objectClass.getClassName(), node.method.member.name));
backend.emitInsn(String.format("addi sp, fp, -%s", size_label), "Set SP to stack frame top.");
sp_off -= (n_args+1)*wordSize;
return A0;
}
public Register analyze(NoneLiteral node) {
return null;
}
public Register analyze(ReturnStmt node) {
return null;
}
public Register analyze(StringLiteral node) {
return null;
}
public Register analyze(UnaryExpr node) {
return null;
}
public Register analyze(WhileStmt node) {
return null;
}
// FIXME: More, of course.
}
/**
* Emits custom code in the CODE segment.
*
* <p>This method is called after emitting the top level and the function bodies for each
* function.
*
* <p>You can use this method to emit anything you want outside of the top level or functions,
* e.g. custom routines that you may want to call from within your code to do common tasks. This
* is not strictly needed. You might not modify this at all and still complete the assignment.
*
* <p>To start you off, here is an implementation of three routines that will be commonly needed
* from within the code you will generate for statements.
*
* <p>The routines are error handlers for operations on None, index out of bounds, and division
* by zero. They never return to their caller. Just jump to one of these routines to throw an
* error and exit the program. For example, to throw an OOB error: backend.emitJ(errorOob, "Go
* to out-of-bounds error and abort");
*/
protected void emitCustomCode() {
emitErrorFunc(errorNone, "Operation on None");
emitErrorFunc(errorDiv, "Division by zero");
emitErrorFunc(errorOob, "Index out of bounds");
}
/** Emit an error routine labeled ERRLABEL that aborts with message MSG. */
private void emitErrorFunc(Label errLabel, String msg) {
backend.emitGlobalLabel(errLabel);
backend.emitLI(A0, ERROR_NONE, "Exit code for: " + msg);
backend.emitLA(A1, constants.getStrConstant(msg), "Load error message as str");
backend.emitADDI(
A1, A1, getAttrOffset(strClass, "__str__"), "Load address of attribute __str__");
backend.emitJ(abortLabel, "Abort");
}
}