[cfe-dev] Compiling FFmpeg

[Daniel Dunbar]

On Fri, Dec 5, 2008 at 3:37 AM, John Kelley <jekelley at apple.com> wrote:
> As mentioned in my last mail, clang has trouble compiling files that
> initialize struct members at declaration . One thing I forgot to
> mention is that clang still produces an object file even after the
> error. This allows make to continue as if everything is fine if it is
> run a second time.

This is a bug! I cannot reproduce however:
--
ddunbar at ozzy:tmp$ cat t.c
int g0[2] = { [1] = 1 };
ddunbar at ozzy:tmp$ ccc -c t.c
t.c:1:13: error: cannot codegen this initializer list with designators yet
int g0[2] = { [1] = 1 };
            ^~~~~~~~~~~
1 diagnostic generated.
ddunbar at ozzy:tmp$ ls -l t.o
ls: t.o: No such file or directory
--

If you can reproduce please file a bug at http://llvm.org/bugs

 - Daniel

> - John
>
> On Dec 5, 2008, at 3:21 AM, John Kelley wrote:
>
>> To familiarize myself with clang I decided to try to compile FFmpeg as
>> I am familiar with the project and the developers first guess when
>> something goes wrong is "gcc is probably doing something stupid
>> again".
>>
>> This might seem like a lot to start off with and I'd tend to agree but
>> less went wrong (so far) than I expected. The main issue thus far is
>> that clang has trouble initializing structures. Below may not be the
>> cleanest code but it was the simplest that I could find that produces
>> an error:
>>
>> (from ffmpeg/libavutil/crc.c)
>>
>> typedef enum {
>>     AV_CRC_8_ATM,
>>     AV_CRC_16_ANSI,
>>     AV_CRC_16_CCITT,
>>     AV_CRC_32_IEEE,
>>     AV_CRC_32_IEEE_LE,  /*< reversed bitorder version of
>> AV_CRC_32_IEEE */
>>     AV_CRC_MAX,         /*< not part of public API! don't use outside
>> lavu */
>> }AVCRCId;
>>
>> static struct {
>>     uint8_t  le;
>>     uint8_t  bits;
>>     uint32_t poly;
>> } av_crc_table_params[AV_CRC_MAX] = {
>>     [AV_CRC_8_ATM]      = { 0,  8,       0x07 },
>>     [AV_CRC_16_ANSI]    = { 0, 16,     0x8005 },
>>     [AV_CRC_16_CCITT]   = { 0, 16,     0x1021 },
>>     [AV_CRC_32_IEEE]    = { 0, 32, 0x04C11DB7 },
>>     [AV_CRC_32_IEEE_LE] = { 1, 32, 0xEDB88320 },
>> };
>>
>> This produces the following error:
>> crc.c:31:37: error: cannot codegen this initializer list with
>> designators yet
>> } av_crc_table_params[AV_CRC_MAX] = {
>>                                     ^
>>
>> I have no problem pitching in to fix this but wanted to make sure that
>> no one else is currently working on it and to ask where I should look
>> to implement this.
>>
>> Also I was planning on taking a shot at the File Manager Speedup
>> project listed in NOTES.txt unless there are any objections.
>>
>> Cheers,
>> John Kelley
>> _______________________________________________
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>> cfe-dev at cs.uiuc.edu
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>
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