gccint: PCH Target

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1 18.27 Parameters for Precompiled Header Validity Checking
1 =========================================================
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1  -- Target Hook: void * TARGET_GET_PCH_VALIDITY (size_t *SZ)
1      This hook returns a pointer to the data needed by
1      'TARGET_PCH_VALID_P' and sets '*SZ' to the size of the data in
1      bytes.
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1  -- Target Hook: const char * TARGET_PCH_VALID_P (const void *DATA,
1           size_t SZ)
1      This hook checks whether the options used to create a PCH file are
1      compatible with the current settings.  It returns 'NULL' if so and
1      a suitable error message if not.  Error messages will be presented
1      to the user and must be localized using '_(MSG)'.
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1      DATA is the data that was returned by 'TARGET_GET_PCH_VALIDITY'
1      when the PCH file was created and SZ is the size of that data in
1      bytes.  It's safe to assume that the data was created by the same
1      version of the compiler, so no format checking is needed.
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1      The default definition of 'default_pch_valid_p' should be suitable
1      for most targets.
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1  -- Target Hook: const char * TARGET_CHECK_PCH_TARGET_FLAGS (int
1           PCH_FLAGS)
1      If this hook is nonnull, the default implementation of
1      'TARGET_PCH_VALID_P' will use it to check for compatible values of
1      'target_flags'.  PCH_FLAGS specifies the value that 'target_flags'
1      had when the PCH file was created.  The return value is the same as
1      for 'TARGET_PCH_VALID_P'.
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1  -- Target Hook: void TARGET_PREPARE_PCH_SAVE (void)
1      Called before writing out a PCH file.  If the target has some
1      garbage-collected data that needs to be in a particular state on
1      PCH loads, it can use this hook to enforce that state.  Very few
1      targets need to do anything here.
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