Bitwise » Forums » Problems with C code generation in ion
RFH
AM
6 posts
#15387 Problems with C code generation in ion
6 months, 3 weeks ago Edited by AM on May 26, 2018, 9:49 a.m. Reason: Initial post

Hi,

When I run ion on the test1 and test2 packages in the bitwise/ion project directory, is runs successfully and creates the .c output files. But when I try to compile those output C files (with both MinGW gcc and Microsoft's cl), I got a long list of errors. When I checked the C files ion generates, I found that it seems to be broken. Here is an excerpt

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
#line 16 "C:\\Users\\user\\bitwise\\ion\\test1\\subtest1\\subtest1.ion"
void test1_subtest1_func2);

#line 753 "C:\\Users\\user\\bitwise\\ion\\test1\\test1.ion"
extern test1_Thing test1_thing;

#line 506
void test1_print_any);

#line 529
void test1_print_type);

#line 147
struct test1_UartCtrl {
    bool tx_enable;
    #line 148
    bool rx_enable;
};

#line 559
void test1_print_typeinfo);

#line 202
union test1_IntOrPtr {
    int i;
    int (*p);
};
 "C:\\\user\\bitwise\\ion\\test1\\subtest1\\subtest1.ion"
void test1_subtest1_func3);


From your streams, this is obviously not happening to you or to other people trying ion, so I can only assume I am making some fundamental mistake in using it. The command I use to compile ion is

1
gcc -o ion main.c


Either works fine. Then I use ion to compile a test package:

1
ion test1


Again, that works, but it generates the broken output file. I must be doing something wrong, but I cannot figure out what. Any help will be appreciated.

I am on a Windows 10 PC. Here is info on compilers I am using.

1
2
3
4
5
6
7
8
9
C:\Users\user\riscv-sim>gcc --version
gcc (GCC) 7.2.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

C:\Users\user\riscv-sim>cl
Microsoft (R) C/C++ Optimizing Compiler Version 19.11.25547 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.


I am using the github code for day 30.

Many thanks,

A.
RFH
AM
6 posts
#15398 Problems with C code generation in ion
6 months, 2 weeks ago

I tracked down the problem to vsnprintf(), used by buf__printf(), in common.c. vsnprintf() is supposed to return the number of characters that would have been written if the buffer was large enough; but in my system, it returns -1 when buf__printf is called aon a non-NULL buffer. So I modified the code in buf__printf() to first use vsnprintf() with a NULL buffer, to get the required size; and then adjust the size of the buffer (if needed):

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
char *buf__printf(char *buf, const char *fmt, ...) {
    va_list args;
    va_start(args, fmt);
    size_t cap = buf_cap(buf) - buf_len(buf);
    int n = 1 + vsnprintf(NULL, 0, fmt, args);
    assert(n > 0);
    va_end(args);
    
    if (n > cap) {
        buf_fit(buf, n + buf_len(buf));
    }
    va_start(args, fmt);
    size_t new_cap = buf_cap(buf) - buf_len(buf);
    n = 1 + vsnprintf(buf_end(buf), new_cap, fmt, args);
    assert(n > 0);
    assert(n <= new_cap);
    va_end(args);

    buf__hdr(buf)->len += n - 1;
    return buf;
}


That seems to work; using the Microsoft cl compiler, now everything works. In gcc, however, one problem still remains: mysterious error messages complaining about an undefined "zu" variable. Is this something to do with the %zu specifier for printf?

Thanks,

A.
pervognsen
Per Vognsen
49 posts / 1 project
#15503 Problems with C code generation in ion
6 months, 1 week ago Edited by Per Vognsen on June 6, 2018, 2:43 a.m.

Sorry for not responding sooner.

We previously had a report of a similar issue with snprintf/vsnprintf with VS 2013, which had a compiler with nominal C99 support but the old non-compliant version of snprintf. I'm guessing what you're seeing is related, since mingw-gcc might use snprintf from msvcrt.dll. I wonder if compiling with -std=c11 fixes it? And I mean compiling the Ion compiler (main.c) that way.
mmozeiko
Mārtiņš Možeiko
1831 posts / 1 project
#15506 Problems with C code generation in ion
6 months, 1 week ago Edited by Mārtiņš Možeiko on June 6, 2018, 5:38 a.m.

mingw by default will use snprintf from msvcrt.dll which does not support even c99. But if you add define __USE_MINGW_ANSI_STDIO=1 before including any std headers, then it will provide its own snprintf which is standard compliant, including c99 specifiers.
pervognsen
Per Vognsen
49 posts / 1 project
#15507 Problems with C code generation in ion
6 months, 1 week ago

Thanks! It's easy for me to add that to my prelude.