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Re: A flaw in dep generation with gcc -MMD?

From
Nguyen Thai Ngoc Duy <pclouds@gmail.com>
Date
Nov 18, 2011, 14:12 UTC
Message-ID
<CACsJy8CKmjq01KoLRzOnnaf6RwFCQJfjxziqKTZW9HDyd8CagA@mail.gmail.com>
In-Reply-To
<CACsJy8BuCdT3rRjc5u6Ex5RRgSbL_0SFF0GW-dTGqet4sG2cwg@mail.gmail.com>
On Fri, Nov 18, 2011 at 6:34 PM, Nguyen Thai Ngoc Duy <pclouds@gmail.com> wrote:
> OK it's not gcc problem. I upgraded to 4.5.3 and still had the same
> problem. I used ccache though. Without ccache, gcc produced correct
> .o.d files.

"gcc -MF depfile -MMD -MP -c -o path/to/file.o" will produce "depfile" with target given by "-o". When ccache runs, it executes "gcc -MF depfile -MMD -MP -E" instead to get the final content for hashing. Notice that "-c -o" combination is replaced by "-E". The latter produces target without leading path.

Not sure if I should report this to ccache or gcc. In the meantime, may be we should recognize the situation and switch off COMPUTE_HEADER_DEPENDENCIES when ccache is used (maybe hard).

-- 
Duy
Previous: Nguyen Thai Ngoc DuyNext: Samuel Bronson
Message 6 of 19 in “A flaw in dep generation with gcc -MMD?”
  1. Nguyen Thai Ngoc DuyNov 18, 2011
  2. Jonathan NiederNov 18, 2011
  3. Nguyen Thai Ngoc DuyNov 18, 2011
  4. Miles BaderNov 18, 2011
  5. Nguyen Thai Ngoc DuyNov 18, 2011
  6. Nguyen Thai Ngoc DuyNov 18, 2011
  7. Samuel BronsonNov 18, 2011
  8. Jonathan NiederNov 18, 2011
  9. Andreas SchwabNov 18, 2011
  10. Nguyen Thai Ngoc DuyNov 19, 2011
  11. Makefile: add option to disable automatic dependency generationJonathan Nieder, Nov 18, 2011
  12. Jonathan NiederNov 18, 2011
  13. Junio C HamanoNov 18, 2011
  14. Jonathan NiederNov 18, 2011
  15. Makefile: add option to disable automatic dependency generationJonathan Nieder, Nov 18, 2011
  16. Makefile: add missing header file dependenciesJonathan Nieder, Nov 18, 2011
  17. Nguyen Thai Ngoc DuyNov 18, 2011
  18. Makefile: explicitly set target name for autogenerated dependenciesJonathan Nieder, Nov 18, 2011
  19. Nguyen Thai Ngoc DuyNov 19, 2011

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