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| -rw-r--r-- | gcc/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/doc/extend.texi | 22 |
2 files changed, 26 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index eb457ba8e1b..578b682403e 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,9 @@ 2009-08-06 Richard Earnshaw <rearnsha@arm.com> + * doc/extend.texi (pcs): Document new attribute for ARM. + +2009-08-06 Richard Earnshaw <rearnsha@arm.com> + * arm.c (pcs_attribute_args): Comment out unsupported attribute variants. diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index b545c328e2c..3435e2c1087 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -2830,6 +2830,28 @@ compiled with more aggressive optimization options that produce faster and larger code, while other functions can be called with less aggressive options. +@item pcs +@cindex @code{pcs} function attribute + +The @code{pcs} attribute can be used to control the calling convention +used for a function on ARM. The attribute takes an argument that specifies +the calling convention to use. + +When compiling using the AAPCS ABI (or a variant of that) then valid +values for the argument are @code{"aapcs"} and @code{"aapcs-vfp"}. In +order to use a variant other than @code{"aapcs"} then the compiler must +be permitted to use the appropriate co-processor registers (i.e., the +VFP registers must be available in order to use @code{"aapcs-vfp"}). +For example, + +@smallexample +/* Argument passed in r0, and result returned in r0+r1. */ +double f2d (float) __attribute__((pcs("aapcs"))); +@end smallexample + +Variadic functions always use the @code{"aapcs"} calling convention and +the compiler will reject attempts to specify an alternative. + @item pure @cindex @code{pure} function attribute Many functions have no effects except the return value and their |
