public override void CGenStmt(Env env, CGenState state) { ExprType ret_type = env.GetCurrentFunction().ReturnType; Int32 stack_size = state.StackSize; if (this.ExprOpt.IsSome) { // Evaluate the Value. this.ExprOpt.Value.CGenValue(state); // If the function returns a struct, copy it to the address given by 8(%ebp). if (this.ExprOpt.Value.Type is StructOrUnionType) { state.MOVL(Reg.EAX, Reg.ESI); state.MOVL(2 * ExprType.SIZEOF_POINTER, Reg.EBP, Reg.EDI); state.MOVL(this.ExprOpt.Value.Type.SizeOf, Reg.ECX); state.CGenMemCpy(); state.MOVL(2 * ExprType.SIZEOF_POINTER, Reg.EBP, Reg.EAX); } // Restore stack size. state.CGenForceStackSizeTo(stack_size); } // Jump to end of the function. state.JMP(state.ReturnLabel); }
public override Reg CGenValue(Env env, CGenState state) { // 1. %eax = &lhs lvalue.CGenAddress(env, state); // 2. push %eax Int32 pos = state.CGenPushLong(Reg.EAX); Reg ret = rvalue.CGenValue(env, state); switch (lvalue.type.kind) { case ExprType.Kind.CHAR: case ExprType.Kind.UCHAR: // pop %ebx // now %ebx = %lhs state.CGenPopLong(pos, Reg.EBX); // *%ebx = %al state.MOVB(Reg.AL, 0, Reg.EBX); return Reg.EAX; case ExprType.Kind.SHORT: case ExprType.Kind.USHORT: // pop %ebx // now %ebx = %lhs state.CGenPopLong(pos, Reg.EBX); // *%ebx = %al state.MOVW(Reg.AX, 0, Reg.EBX); return Reg.EAX; case ExprType.Kind.LONG: case ExprType.Kind.ULONG: case ExprType.Kind.POINTER: // pop %ebx // now %ebx = &lhs state.CGenPopLong(pos, Reg.EBX); // *%ebx = %al state.MOVL(Reg.EAX, 0, Reg.EBX); return Reg.EAX; case ExprType.Kind.FLOAT: // pop %ebx // now %ebx = &lhs state.CGenPopLong(pos, Reg.EBX); // *%ebx = %st(0) state.FSTS(0, Reg.EBX); return Reg.ST0; case ExprType.Kind.DOUBLE: // pop %ebx // now %ebx = &lhs state.CGenPopLong(pos, Reg.EBX); // *%ebx = %st(0) state.FSTL(0, Reg.EBX); return Reg.ST0; case ExprType.Kind.STRUCT_OR_UNION: // pop %edi // now %edi = &lhs state.CGenPopLong(pos, Reg.EDI); // %esi = &rhs state.MOVL(Reg.EAX, Reg.ESI); // %ecx = nbytes state.MOVL(lvalue.type.SizeOf, Reg.ECX); state.CGenMemCpy(); // %eax = &lhs state.MOVL(Reg.EDI, Reg.EAX); return Reg.EAX; case ExprType.Kind.FUNCTION: case ExprType.Kind.VOID: case ExprType.Kind.ARRAY: case ExprType.Kind.INCOMPLETE_ARRAY: default: throw new InvalidProgramException("cannot assign to a " + type.kind.ToString()); } }
public override Reg CGenValue(Env env, CGenState state) { // GCC's IA-32 calling convention // Caller is responsible to push all arguments to the stack in reverse order. // Each argument is at least aligned to 4 bytes - even a char would take 4 bytes. // The return value is stored in %eax, or %st(0), if it is a scalar. // // The stack would look like this after pushing all the arguments: // +--------+ // | .... | // +--------+ // | argn | // +--------+ // | .... | // +--------+ // | arg2 | // +--------+ // | arg1 | // +--------+ <- %esp before call // // Things are different with structs and unions. // Since structs may not fit in 4 bytes, it has to be returned in memory. // Caller allocates a chunk of memory for the struct and push the address of it as an extra argument. // Callee returns %eax with that address. // // The stack would look like this after pushing all the arguments: // +--------+ // +--> | struct | <- struct should be returned here. // | +--------+ // | | argn | // | +--------+ // | | .... | // | +--------+ // | | arg2 | // | +--------+ // | | arg1 | // | +--------+ // +----| addr | <- %esp before call // +--------+ // state.NEWLINE(); state.COMMENT($"Before pushing the arguments, stack size = {state.StackSize}."); var r_pack = Utils.PackArguments(args.Select(_ => _.type).ToList()); Int32 pack_size = r_pack.Item1; IReadOnlyList<Int32> offsets = r_pack.Item2; if (type is TStructOrUnion) { // If the function returns a struct // Allocate space for return value. state.COMMENT("Allocate space for returning stack."); state.CGenExpandStackWithAlignment(type.SizeOf, type.Alignment); // Temporarily store the address in %eax. state.MOVL(Reg.ESP, Reg.EAX); // add an extra argument and move all other arguments upwards. pack_size += ExprType.SIZEOF_POINTER; offsets = offsets.Select(_ => _ + ExprType.SIZEOF_POINTER).ToList(); } // Allocate space for arguments. // If returning struct, the extra pointer is included. state.COMMENT($"Arguments take {pack_size} bytes."); state.CGenExpandStackBy(pack_size); state.NEWLINE(); // Store the address as the first argument. if (type is TStructOrUnion) { state.COMMENT("Putting extra argument for struct return address."); state.MOVL(Reg.EAX, 0, Reg.ESP); state.NEWLINE(); } // This is the stack size before calling the function. Int32 header_base = -state.StackSize; // Push the arguments onto the stack in reverse order for (Int32 i = args.Count; i-- > 0;) { Expr arg = args[i]; Int32 pos = header_base + offsets[i]; state.COMMENT($"Argument {i} is at {pos}"); Reg ret = arg.CGenValue(env, state); switch (arg.type.kind) { case ExprType.Kind.ARRAY: case ExprType.Kind.CHAR: case ExprType.Kind.UCHAR: case ExprType.Kind.SHORT: case ExprType.Kind.USHORT: case ExprType.Kind.LONG: case ExprType.Kind.ULONG: case ExprType.Kind.POINTER: if (ret != Reg.EAX) { throw new InvalidProgramException(); } state.MOVL(Reg.EAX, pos, Reg.EBP); break; case ExprType.Kind.DOUBLE: if (ret != Reg.ST0) { throw new InvalidProgramException(); } state.FSTPL(pos, Reg.EBP); break; case ExprType.Kind.FLOAT: if (ret != Reg.ST0) { throw new InvalidProgramException(); } state.FSTPL(pos, Reg.EBP); break; case ExprType.Kind.STRUCT_OR_UNION: if (ret != Reg.EAX) { throw new InvalidProgramException(); } state.MOVL(Reg.EAX, Reg.ESI); state.LEA(pos, Reg.EBP, Reg.EDI); state.MOVL(arg.type.SizeOf, Reg.ECX); state.CGenMemCpy(); break; default: throw new InvalidProgramException(); } state.NEWLINE(); } // When evaluating arguments, the stack might be changed. // We must restore the stack. state.CGenForceStackSizeTo(-header_base); // Get function address if (func.type is TFunction) { func.CGenAddress(env, state); } else if (func.type is TPointer) { func.CGenValue(env, state); } else { throw new InvalidProgramException(); } state.CALL("*%eax"); state.COMMENT("Function returned."); state.NEWLINE(); if (type.kind == ExprType.Kind.FLOAT || type.kind == ExprType.Kind.DOUBLE) { return Reg.ST0; } else { return Reg.EAX; } }
public override void CGenStmt(Env env, CGenState state) { ExprType ret_type = env.GetCurrentFunction().ret_t; Int32 stack_size = state.StackSize; // Evaluate the value. expr.CGenValue(env, state); // If the function returns a struct, copy it to the address given by 8(%ebp). if (expr.type is TStructOrUnion) { state.MOVL(Reg.EAX, Reg.ESI); state.MOVL(2 * ExprType.SIZEOF_POINTER, Reg.EBP, Reg.EDI); state.MOVL(expr.type.SizeOf, Reg.ECX); state.CGenMemCpy(); state.MOVL(2 * ExprType.SIZEOF_POINTER, Reg.EBP, Reg.EAX); } // Restore stack size. state.CGenForceStackSizeTo(stack_size); // Jump to end of the function. state.JMP(state.ReturnLabel); }
// * function; // * extern function; // * static function; // * obj; // * obj = Init; // * static obj; // * static obj = Init; // * extern obj; // * extern obj = Init; public void CGenDecln(Env env, CGenState state) { if (env.IsGlobal()) { if (this.initr.IsSome) { Initr initr = this.initr.Value; switch (this.scs) { case StorageClass.AUTO: state.GLOBL(this.name); break; case StorageClass.EXTERN: throw new InvalidProgramException(); case StorageClass.STATIC: break; case StorageClass.TYPEDEF: // Ignore. return; default: throw new InvalidProgramException(); } state.DATA(); state.ALIGN(ExprType.ALIGN_LONG); state.CGenLabel(this.name); Int32 last = 0; initr.Iterate(this.type, (Int32 offset, Expr expr) => { if (offset > last) { state.ZERO(offset - last); } if (!expr.IsConstExpr) { throw new InvalidOperationException("Cannot initialize with non-const expression."); } switch (expr.Type.Kind) { // TODO: without const char/short, how do I initialize? case ExprTypeKind.CHAR: case ExprTypeKind.UCHAR: case ExprTypeKind.SHORT: case ExprTypeKind.USHORT: throw new NotImplementedException(); case ExprTypeKind.LONG: state.LONG(((ConstLong)expr).Value); break; case ExprTypeKind.ULONG: state.LONG((Int32)((ConstULong)expr).Value); break; case ExprTypeKind.POINTER: state.LONG((Int32)((ConstPtr)expr).Value); break; case ExprTypeKind.FLOAT: byte[] float_bytes = BitConverter.GetBytes(((ConstFloat)expr).Value); Int32 intval = BitConverter.ToInt32(float_bytes, 0); state.LONG(intval); break; case ExprTypeKind.DOUBLE: byte[] double_bytes = BitConverter.GetBytes(((ConstDouble)expr).Value); Int32 first_int = BitConverter.ToInt32(double_bytes, 0); Int32 second_int = BitConverter.ToInt32(double_bytes, 4); state.LONG(first_int); state.LONG(second_int); break; default: throw new InvalidProgramException(); } last = offset + expr.Type.SizeOf; }); } else { // Global without initialization. switch (this.scs) { case StorageClass.AUTO: // .comm name,size,align break; case StorageClass.EXTERN: break; case StorageClass.STATIC: // .local name // .comm name,size,align state.LOCAL(this.name); break; case StorageClass.TYPEDEF: // Ignore. return; default: throw new InvalidProgramException(); } if (this.type.Kind != ExprTypeKind.FUNCTION) { state.COMM(this.name, this.type.SizeOf, ExprType.ALIGN_LONG); } } state.NEWLINE(); } else { // stack object state.CGenExpandStackTo(env.StackSize, ToString()); Int32 stack_size = env.StackSize; // pos should be equal to stack_size, but whatever... Int32 pos = env.Find(this.name).Value.Offset; if (this.initr.IsNone) { return; } Initr initr = this.initr.Value; initr.Iterate(this.type, (Int32 offset, Expr expr) => { Reg ret = expr.CGenValue(state); switch (expr.Type.Kind) { case ExprTypeKind.CHAR: case ExprTypeKind.UCHAR: state.MOVB(Reg.EAX, pos + offset, Reg.EBP); break; case ExprTypeKind.SHORT: case ExprTypeKind.USHORT: state.MOVW(Reg.EAX, pos + offset, Reg.EBP); break; case ExprTypeKind.DOUBLE: state.FSTPL(pos + offset, Reg.EBP); break; case ExprTypeKind.FLOAT: state.FSTPS(pos + offset, Reg.EBP); break; case ExprTypeKind.LONG: case ExprTypeKind.ULONG: case ExprTypeKind.POINTER: state.MOVL(Reg.EAX, pos + offset, Reg.EBP); break; case ExprTypeKind.STRUCT_OR_UNION: state.MOVL(Reg.EAX, Reg.ESI); state.LEA(pos + offset, Reg.EBP, Reg.EDI); state.MOVL(expr.Type.SizeOf, Reg.ECX); state.CGenMemCpy(); break; case ExprTypeKind.ARRAY: case ExprTypeKind.FUNCTION: throw new InvalidProgramException($"How could a {expr.Type.Kind} be in a init list?"); default: throw new InvalidProgramException(); } state.CGenForceStackSizeTo(stack_size); }); } // stack object }
public override Reg CGenValue(CGenState state) { // GCC's IA-32 calling convention // Caller is responsible to push all arguments to the stack in reverse order. // Each argument is at least aligned to 4 bytes - even a char would take 4 bytes. // The return Value is stored in %eax, or %st(0), if it is a scalar. // // The stack would look like this after pushing all the arguments: // +--------+ // | .... | // +--------+ // | argn | // +--------+ // | .... | // +--------+ // | arg2 | // +--------+ // | arg1 | // +--------+ <- %esp before call // // Things are different with structs and unions. // Since structs may not fit in 4 bytes, it has to be returned in memory. // Caller allocates a chunk of memory for the struct and push the address of it as an extra argument. // Callee returns %eax with that address. // // The stack would look like this after pushing all the arguments: // +--------+ // +--> | struct | <- struct should be returned here. // | +--------+ // | | argn | // | +--------+ // | | .... | // | +--------+ // | | arg2 | // | +--------+ // | | arg1 | // | +--------+ // +----| addr | <- %esp before call // +--------+ // state.NEWLINE(); state.COMMENT($"Before pushing the arguments, stack size = {state.StackSize}."); var r_pack = Utils.PackArguments(this.Args.Select(_ => _.Type).ToList()); Int32 pack_size = r_pack.Item1; IReadOnlyList <Int32> offsets = r_pack.Item2; if (this.Type is StructOrUnionType) { // If the function returns a struct // Allocate space for return Value. state.COMMENT("Allocate space for returning stack."); state.CGenExpandStackWithAlignment(this.Type.SizeOf, this.Type.Alignment); // Temporarily store the address in %eax. state.MOVL(Reg.ESP, Reg.EAX); // add an extra argument and move all other arguments upwards. pack_size += ExprType.SIZEOF_POINTER; offsets = offsets.Select(_ => _ + ExprType.SIZEOF_POINTER).ToList(); } // Allocate space for arguments. // If returning struct, the extra pointer is included. state.COMMENT($"Arguments take {pack_size} bytes."); state.CGenExpandStackBy(pack_size); state.NEWLINE(); // Store the address as the first argument. if (this.Type is StructOrUnionType) { state.COMMENT("Putting extra argument for struct return address."); state.MOVL(Reg.EAX, 0, Reg.ESP); state.NEWLINE(); } // This is the stack size before calling the function. Int32 header_base = -state.StackSize; // Push the arguments onto the stack in reverse order for (Int32 i = this.Args.Count; i-- > 0;) { Expr arg = this.Args[i]; Int32 pos = header_base + offsets[i]; state.COMMENT($"Argument {i} is at {pos}"); Reg ret = arg.CGenValue(state); switch (arg.Type.Kind) { case ExprTypeKind.ARRAY: case ExprTypeKind.CHAR: case ExprTypeKind.UCHAR: case ExprTypeKind.SHORT: case ExprTypeKind.USHORT: case ExprTypeKind.LONG: case ExprTypeKind.ULONG: case ExprTypeKind.POINTER: if (ret != Reg.EAX) { throw new InvalidProgramException(); } state.MOVL(Reg.EAX, pos, Reg.EBP); break; case ExprTypeKind.DOUBLE: if (ret != Reg.ST0) { throw new InvalidProgramException(); } state.FSTPL(pos, Reg.EBP); break; case ExprTypeKind.FLOAT: if (ret != Reg.ST0) { throw new InvalidProgramException(); } state.FSTPL(pos, Reg.EBP); break; case ExprTypeKind.STRUCT_OR_UNION: if (ret != Reg.EAX) { throw new InvalidProgramException(); } state.MOVL(Reg.EAX, Reg.ESI); state.LEA(pos, Reg.EBP, Reg.EDI); state.MOVL(arg.Type.SizeOf, Reg.ECX); state.CGenMemCpy(); break; default: throw new InvalidProgramException(); } state.NEWLINE(); } // When evaluating arguments, the stack might be changed. // We must restore the stack. state.CGenForceStackSizeTo(-header_base); // Get function address if (this.Func.Type is FunctionType) { this.Func.CGenAddress(state); } else if (this.Func.Type is PointerType) { this.Func.CGenValue(state); } else { throw new InvalidProgramException(); } state.CALL("*%eax"); state.COMMENT("Function returned."); state.NEWLINE(); if (this.Type.Kind == ExprTypeKind.FLOAT || this.Type.Kind == ExprTypeKind.DOUBLE) { return(Reg.ST0); } return(Reg.EAX); }
public override Reg CGenValue(CGenState state) { // 1. %eax = &left this.Left.CGenAddress(state); // 2. push %eax Int32 pos = state.CGenPushLong(Reg.EAX); Reg ret = this.Right.CGenValue(state); switch (this.Left.Type.Kind) { case ExprTypeKind.CHAR: case ExprTypeKind.UCHAR: // pop %ebx // now %ebx = %Left state.CGenPopLong(pos, Reg.EBX); // *%ebx = %al state.MOVB(Reg.AL, 0, Reg.EBX); return(Reg.EAX); case ExprTypeKind.SHORT: case ExprTypeKind.USHORT: // pop %ebx // now %ebx = %Left state.CGenPopLong(pos, Reg.EBX); // *%ebx = %al state.MOVW(Reg.AX, 0, Reg.EBX); return(Reg.EAX); case ExprTypeKind.LONG: case ExprTypeKind.ULONG: case ExprTypeKind.POINTER: // pop %ebx // now %ebx = &Left state.CGenPopLong(pos, Reg.EBX); // *%ebx = %al state.MOVL(Reg.EAX, 0, Reg.EBX); return(Reg.EAX); case ExprTypeKind.FLOAT: // pop %ebx // now %ebx = &Left state.CGenPopLong(pos, Reg.EBX); // *%ebx = %st(0) state.FSTS(0, Reg.EBX); return(Reg.ST0); case ExprTypeKind.DOUBLE: // pop %ebx // now %ebx = &Left state.CGenPopLong(pos, Reg.EBX); // *%ebx = %st(0) state.FSTL(0, Reg.EBX); return(Reg.ST0); case ExprTypeKind.STRUCT_OR_UNION: // pop %edi // now %edi = &Left state.CGenPopLong(pos, Reg.EDI); // %esi = &Right state.MOVL(Reg.EAX, Reg.ESI); // %ecx = nbytes state.MOVL(this.Left.Type.SizeOf, Reg.ECX); state.CGenMemCpy(); // %eax = &Left state.MOVL(Reg.EDI, Reg.EAX); return(Reg.EAX); case ExprTypeKind.FUNCTION: case ExprTypeKind.VOID: case ExprTypeKind.ARRAY: case ExprTypeKind.INCOMPLETE_ARRAY: default: throw new InvalidProgramException("cannot assign to a " + this.Type.Kind); } }
// * function; // * extern function; // * static function; // * obj; // * obj = init; // * static obj; // * static obj = init; // * extern obj; // * extern obj = init; public void CGenDecln(Env env, CGenState state) { if (env.IsGlobal()) { if (this.initr.IsSome) { Initr initr = this.initr.Value; switch (scs) { case SCS.AUTO: state.GLOBL(name); break; case SCS.EXTERN: throw new InvalidProgramException(); case SCS.STATIC: break; case SCS.TYPEDEF: // Ignore. return; default: throw new InvalidProgramException(); } state.DATA(); state.ALIGN(ExprType.ALIGN_LONG); state.CGenLabel(name); Int32 last = 0; initr.Iterate(type, (Int32 offset, Expr expr) => { if (offset > last) { state.ZERO(offset - last); } if (!expr.IsConstExpr) { throw new InvalidOperationException("Cannot initialize with non-const expression."); } switch (expr.type.kind) { // TODO: without const char/short, how do I initialize? case ExprType.Kind.CHAR: case ExprType.Kind.UCHAR: case ExprType.Kind.SHORT: case ExprType.Kind.USHORT: throw new NotImplementedException(); case ExprType.Kind.LONG: state.LONG(((ConstLong)expr).value); break; case ExprType.Kind.ULONG: state.LONG((Int32)((ConstULong)expr).value); break; case ExprType.Kind.POINTER: state.LONG((Int32)((ConstPtr)expr).value); break; case ExprType.Kind.FLOAT: byte[] float_bytes = BitConverter.GetBytes(((ConstFloat)expr).value); Int32 intval = BitConverter.ToInt32(float_bytes, 0); state.LONG(intval); break; case ExprType.Kind.DOUBLE: byte[] double_bytes = BitConverter.GetBytes(((ConstDouble)expr).value); Int32 first_int = BitConverter.ToInt32(double_bytes, 0); Int32 second_int = BitConverter.ToInt32(double_bytes, 4); state.LONG(first_int); state.LONG(second_int); break; default: throw new InvalidProgramException(); } last = offset + expr.type.SizeOf; }); } else { // Global without initialization. switch (scs) { case SCS.AUTO: // .comm name,size,align break; case SCS.EXTERN: break; case SCS.STATIC: // .local name // .comm name,size,align state.LOCAL(name); break; case SCS.TYPEDEF: // Ignore. return; default: throw new InvalidProgramException(); } if (type.kind != ExprType.Kind.FUNCTION) { state.COMM(name, type.SizeOf, ExprType.ALIGN_LONG); } } state.NEWLINE(); } else { // stack object state.CGenExpandStackTo(env.StackSize, ToString()); Int32 stack_size = env.StackSize; // pos should be equal to stack_size, but whatever... Int32 pos = env.Find(name).Value.offset; if (this.initr.IsNone) { return; } Initr initr = this.initr.Value; initr.Iterate(type, (Int32 offset, Expr expr) => { Reg ret = expr.CGenValue(env, state); switch (expr.type.kind) { case ExprType.Kind.CHAR: case ExprType.Kind.UCHAR: state.MOVB(Reg.EAX, pos + offset, Reg.EBP); break; case ExprType.Kind.SHORT: case ExprType.Kind.USHORT: state.MOVW(Reg.EAX, pos + offset, Reg.EBP); break; case ExprType.Kind.DOUBLE: state.FSTPL(pos + offset, Reg.EBP); break; case ExprType.Kind.FLOAT: state.FSTPS(pos + offset, Reg.EBP); break; case ExprType.Kind.LONG: case ExprType.Kind.ULONG: case ExprType.Kind.POINTER: state.MOVL(Reg.EAX, pos + offset, Reg.EBP); break; case ExprType.Kind.STRUCT_OR_UNION: state.MOVL(Reg.EAX, Reg.ESI); state.LEA(pos + offset, Reg.EBP, Reg.EDI); state.MOVL(expr.type.SizeOf, Reg.ECX); state.CGenMemCpy(); break; case ExprType.Kind.ARRAY: case ExprType.Kind.FUNCTION: throw new InvalidProgramException($"How could a {expr.type.kind} be in a init list?"); default: throw new InvalidProgramException(); } state.CGenForceStackSizeTo(stack_size); }); } // stack object }