TugBoat - Clipper to C compiler

TugBoat - new compiler from a Clipper to C

TugBoat - intellectual additional compiler from the language a Clipper into the language C.

• It is the additional compiler, means, you can use it together with the standard compiler of the language a Clipper.
• It is the compiler into the language C, means, you can increase speed of the applications approximately twice.
• It is the intellectual compiler, means, you can detect semantic errors at a stage of compilation.
• And, certainly, some new possibilities

From the very beginning for me the task consist in acceleration of execution of existing Clippers - programs. I shall be repeated, “existing”. That is if the developer used the library QWERTY_for_Clipper of the left developer with all source texts — he can speed up the application including speed up functions them of this library. If he uses the library ASDFG_for_Clipper of the right developer and source texts of this library no in limits of reach — well that, it is possible to speed up operation only of code, and the another's code should be used, "as is".

How it works? Well, I simply create C-code, and on the "C" language 85 % of a Clipper is written. Naturally, it can work together, if all is made correctly. The list of my defects look in “Bugs”. More in detail mechanism of operation read further.

In the beginning there was an idea. “ If the interpreter of a Clipper is written mostly on C and fulfils in main decoding of the byte-code in calls appropriate C of functions, maybe, to try to compile the source texts on a Clipper to C - program, with direct calls of these functions? ”

The first variant TugBoat about it also did. C-code consisting entirely of calls of other functions was derivated. The speed has increased, but not it is a little - on tens percents. The lion's share of time was borrowed by runtime check of types.

Following step was detection and selection of a static type of variables. Especially of type “whole”, “ long whole ”, “logical”, “date”, the operations above which can be fulfilled without engaging the Clipper - computer. Here “pseudo-intelligence” in the compiler (see below) also has appeared

But all the same turning out C-code looked obscenely. A reason — bad practice N-level of addressing in the clippers arrays. But someone wrote, and to respond me! In the Clippers program

f [1] [2] [3] + = a [4] [5] [6]

Looks is almost acceptable. In C-program it looks simply awfully. Also it was necessary to add the classical global optimizer — with removal of the common subexpressions and cleaning of cycles upwards. As a rule, after pass of optimization C-code on 30 % becomes shorter (and a little bit faster). Now output code looks better:

More in detail about the mechanism of operation look in “Theory” and “Histories”

The task of calculation of static types for the language with dynamic types, certainly, is difficult. Nevertheless, for the language LISP she for a long time is solved. Remember the Japanese project of the COMPUTER of fifth generation? Then.

I have made it. For example, you will see something like:

Here “pseudo-intelligence” in the compiler — simply inside him also has appeared there is an error of calculation of a static type in that place, where in the program there would be a violation of runtime check of types (for example, 1 + “1”, or 2 > nil — all this expressions with violations of types). For example:

In detail to describe here, as the static types are calculated, I can not (it is three passes of the compiler, that is words it will be very long and consequently boringly). The god will give, the commercially acceptable variant of translation TugBoat on “ Open Source ” will turn up, then see. Well and if such variant will not be — well that, it is necessary more - less in detail to describe. But later. That is I do not know when.

It is possible to describe types of parameters of the function, for example:

external function qwerty(__integer,__integer|__real,__array)__nil

Syntax of the description EXTERNAL of functions:

Where "arg" or "returned" is

[Type] | [the type] |...

That is it is possible to write, for example:

Syntax of the description STATIC of functions:

Where "arg" or "returned" same

Warning: all descriptions of functions should be in the beginning of the file

Syntax of variables with types:

Where [round] there is one of variants:

Certainly, you know it, but, nevertheless, I shall repeat the initial data

• CA-Clipper - interpreter. After call of the compiler CLIPPER.EXE there is a file with the extension .OBJ, but he does not contain the machine code for the processor Intel. Really file with the extension .OBJ contains the code for the virtual computer CA-Clipper (P-code) and the small portion of the "true" code for call of the emulator of the virtual computer (is possible to see in the debugger, it is the "call PLANKTON" command)
• The code of the emulator of the virtual computer CA-Clipper is in the library CLIPPER.LIB in the file PLANKTON.
• For execution of Clippers - programs the procedure PLANKTON fulfils:
• Definition of the address of the following command
• Its decoding
• Call of the procedure, appropriate to the instruction code

• All local variable and temporary results are stored(kept) in the Clipper - computer in the simulated stack as data structures till 14 bytes, and on first byte the integer is defined, what is it -, string or array etc. That is to add unit to a variable in a Clipper — means:
• To place in the stack a value
• To place in the stack unit
• To fulfil the command of addition, that is
• To check up types of the last two variables in the stack
• If it is strings — to fulfil concatenation
• If number and date — to increase date
• If two numbers from a floating point — that to combine
• If an integer and number from a floating point — to reduce both to a floating point and to combine
• If two integers, — that simply to combine
• To write from the stack in a variable

The variables with names conterminous to keywords are unavailable

" Protected mode " from under Blinker is extremely astable, ExoSpace - it is very good