Use GCC's __attribute__((const)) to reduce code size

__attribute__((const)) is mainly intended for the compiler to optimize
away repeated calls to a function that the compiler knows will return
the same value repeatedly.

By adding __attribute__((const)), the compiler can choose to call the
function just once and cache the return value.  Therefore, this yields
code size reduction.

Here are the reference results by arm-eabi-size for crespo device:

[before]
   text    data     bss     dec     hex filename
 267715   10132   45948  323795   4f0d3

[after]
   text    data     bss     dec     hex filename
 267387   10132   45948  323467   4ef8b

Change-Id: I1d80465c0f88158449702d4dc6398a130eb77195
headers: Unbreak some ARM syscalls

Restore the outside-kernel exclusion for some syscalls that was
removed by change I959b64280e184655ef8c713aa79f9e23cb1f7df4,
since these syscalls are used elsewhere.

Change-Id: I5b5bf3d78edd137e820d25281a375966b6c009ec
Bionic/libm: fast neon pow() for small x,y.

Add a fast neon version of pow() suitable for relatively small
positive x and y (between 0 and 4).  Run the standard
implementation in all other cases.  Gives approximately 60%
performance improvement to AnTuTu FPU scores

Change-Id: I97e0712daeb2740764b26a44be0caaa39c481453
Bionic/libm: Prefer branches and VFP ABI.

For internal functions set gcc attribute "aapcs-vfp" for ARM
and use -fno-if-conversion to prefer branches over predicated
instructions (improves performance on architectures with good
branch prediction).

Change-Id: I8424e0e82a19d35e7e3b6e3e122dcdecdd5426fd
Bionic/libm: add assembly versions of sin/cos.

Add assembly versions of sin/cos with integrated remainder pi/2
calculation.  Directly extracted from binary libm.so compiled with
__ieee754_rem_pio2 calls inlined.

Change-Id: Ia093f420e58e794635e3a5f09e8236ae7601f1f6
Bionic/libm: Pow optimizations and bug fixes.

Use VFP calling convention for pow_neon handoff function by default.
Fix register usage collision between two different polynomial
coefficients in pow_neon.  Remove conditional execution in pow_neon
and replace with branching.

Change-Id: I76095f4a006e2fb01a53943b66fd69bfa1fd3033
Bionic/libm: Add precision-correct de-serialize sin/cos.

Modify sin/cos to improve performance while retaining bit-for-bit
accuracy with existing algorithm.

Change-Id: Iaba2dd731cd015732744705dad8bddb713b43067
libm: optimistic pow calling.

Call optimized pow optimistically and revert to full range
implementation if we detect an out-of-range input.

Change-Id: I6f3aa734adbf99484b7ff70736ef83a41e5815b8
libm: sqrt and sqrtf via ARM vsqrt instruction

Optimized sqrt and sqrtf for arm by using hardware
opcode for sqrt rather than generic slow portable
code.

Change-Id: I84694159577aef6418710548085d8149c45e0e3f
Bionic/libm: Remove extra vmov from sin/cos.

Move integer representations of x bits on the integer side rather
than moving them to and from the FP registers.

Change-Id: I1895db385c9616cdae9ab6403f392dfbae292adc
Bionic/libm: enable optimized math functions on more QCOM targets.

allow more QCOM targets to use optimized math functions.

Change-Id: I76ee1bf951ae1c8397fef3af6e9937ed8cad9b62
libm: Fix multiple inclusion warning

Change-Id: Ifa732ec52fb582c34512cd1d09d918199ae7395e
libc: Add Scorpion-optimized memcpy and memset

 * Optimized routines from Qualcomm for msm8660 class SoCs
 * Enable with TARGET_CPU_VARIANT := scorpion

Change-Id: I01d0f22efba5a418ddd20fca0d0c570d855e0f6f
libc: Use the fast strlen on Scorpion too

Change-Id: I9ba50a469de27269adc008c2a96767830ad6b70b
libc: Add NEON optimized memmove

ported from cm10.1

bionic-benchmarks on cortex-a9
generic:
BM_string_memmove/8    50000000         67   119.35 MiB/s
BM_string_memmove/64   10000000        175   364.59 MiB/s
BM_string_memmove/512   1000000       1078   474.86 MiB/s
BM_string_memmove/1K    1000000       2072   494.20 MiB/s
BM_string_memmove/8K     100000      16400   499.50 MiB/s
BM_string_memmove/16K     50000      32293   507.35 MiB/s
BM_string_memmove/32K     50000      66585   492.12 MiB/s
BM_string_memmove/64K     10000     160435   408.49 MiB/s

NEON-optimized:
BM_string_memmove/8   100000000         25   319.06 MiB/s
BM_string_memmove/64   50000000         43  1472.60 MiB/s
BM_string_memmove/512  10000000        247  2069.74 MiB/s
BM_string_memmove/1K    5000000        463  2210.08 MiB/s
BM_string_memmove/8K     500000       3465  2363.69 MiB/s
BM_string_memmove/16K    500000       6894  2376.30 MiB/s
BM_string_memmove/32K    100000      15490  2115.38 MiB/s
BM_string_memmove/64K     50000      42097  1556.75 MiB/s

Change-Id: I89253a01fb811438089e16320ac265177a2ca152

Conflicts:
	libc/Android.mk
libc: krait: Re-factor high-performance memcpy for thumb2

The majority of libc under bionic is built for thumb2.  Refactor the
high performance memcpy used in previous builds for thumb2, including
information that can be used for stack-unwinding.

Change-Id: Ib5f7ab354f39313758402ec02b0aea27b15d45fa

Conflicts:
	libc/arch-arm/krait/bionic/memcpy_base.S
(cherry picked from commit cdeb493351044c3116fc0d42a64f33f8215a5886)
(cherry picked from commit 0c524faa937b40178915c9478599b754b6f8f78d)
Merge github.com:CarbonDev/android_bionic into kk4.4

Conflicts:
	libc/arch-arm/arm.mk