RealView Compilation Tools - ARM Information Center

Compiler-specific Features
4.3.11 __attribute__((notailcall))
This function attribute prevents tailcalling of the function. That is, the function is always
called with a branch-and-link even if (because the call occurs at the end of a function)
it could be transferred to by a branch.
See also
• __attribute__((nomerge)) on page 4-35
• --retain=option on page 2-113.
4.3.12 __attribute__((pure))
Many functions have no effects except to return a value, and that the return value
depends only on the parameters and global variables. Functions of this kind can be
subject to data flow analysis and might be eliminated.
Note
This function attribute is a GNU compiler extension that is supported by the ARM
compiler.
Although related, this function attribute is not equivalent to the __pure keyword. The
function attribute equivalent to __pure is __attribute__((const)).
Example
int Function_Attributes_pure_0(int b) __attribute__ ((pure));
int Function_Attributes_pure_0(int b)
{
static int aStatic;
aStatic++;
return b++;
}
int Function_Attributes_pure_2(int b)
{
int aLocal=0;
aLocal += Function_Attributes_pure_0(b);
return 0;
}
The call to Function_Attributes_pure_0 in this example might be eliminated because its
result is not used.
ARM DUI 0348C Copyright © 2007-2010 ARM. All rights reserved. 4-37
ID101213
Non-Confidential,