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platform: fix unaligned 64-bit accesses on AArch32 #702

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merged 1 commit into from
Jul 25, 2018
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platform: fix unaligned 64-bit accesses on AArch32 #702

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41 changes: 31 additions & 10 deletions c/common/platform.h
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Original file line number Diff line number Diff line change
Expand Up @@ -187,7 +187,14 @@ To apply compiler hint, enclose the branching condition into macros, like this:

#if (defined(__ARM_ARCH) && (__ARM_ARCH == 8)) || \
defined(__aarch64__) || defined(__ARM64_ARCH_8__)
#define BROTLI_TARGET_ARMV8
#define BROTLI_TARGET_ARMV8_ANY

#if defined(__ARM_32BIT_STATE)
#define BROTLI_TARGET_ARMV8_32
#elif defined(__ARM_64BIT_STATE)
#define BROTLI_TARGET_ARMV8_64
#endif

#endif /* ARMv8 */

#if defined(__i386) || defined(_M_IX86)
Expand All @@ -210,7 +217,7 @@ To apply compiler hint, enclose the branching condition into macros, like this:
#define BROTLI_64_BITS 1
#elif defined(BROTLI_BUILD_32_BIT)
#define BROTLI_64_BITS 0
#elif defined(BROTLI_TARGET_X64) || defined(BROTLI_TARGET_ARMV8) || \
#elif defined(BROTLI_TARGET_X64) || defined(BROTLI_TARGET_ARMV8_64) || \
defined(BROTLI_TARGET_POWERPC64) || defined(BROTLI_TARGET_RISCV64)
#define BROTLI_64_BITS 1
#else
Expand Down Expand Up @@ -261,7 +268,7 @@ To apply compiler hint, enclose the branching condition into macros, like this:
#if defined(BROTLI_BUILD_PORTABLE)
#define BROTLI_ALIGNED_READ (!!1)
#elif defined(BROTLI_TARGET_X86) || defined(BROTLI_TARGET_X64) || \
defined(BROTLI_TARGET_ARMV7) || defined(BROTLI_TARGET_ARMV8) || \
defined(BROTLI_TARGET_ARMV7) || defined(BROTLI_TARGET_ARMV8_ANY) || \
defined(BROTLI_TARGET_RISCV64)
/* Allow unaligned read only for white-listed CPUs. */
#define BROTLI_ALIGNED_READ (!!0)
Expand Down Expand Up @@ -306,15 +313,29 @@ static BROTLI_INLINE void BrotliUnalignedWrite64(void* p, uint64_t v) {
}
#else /* BROTLI_64_BITS */
/* Avoid emitting LDRD / STRD, which require properly aligned address. */
/* If __attribute__(aligned) is available, use that. Otherwise, memcpy. */

#if BROTLI_GNUC_HAS_ATTRIBUTE(aligned, 2, 7, 0)
typedef __attribute__((aligned(1))) uint64_t unaligned_uint64_t;

static BROTLI_INLINE uint64_t BrotliUnalignedRead64(const void* p) {
const uint32_t* dwords = (const uint32_t*)p;
return dwords[0] | ((uint64_t)dwords[1] << 32);
return (uint64_t) ((unaligned_uint64_t*) p)[0];
}
static BROTLI_INLINE void BrotliUnalignedWrite64(void* p, uint64_t v) {
uint32_t* dwords = (uint32_t *)p;
dwords[0] = (uint32_t)v;
dwords[1] = (uint32_t)(v >> 32);
unaligned_uint64_t* dwords = (unaligned_uint64_t*) p;
dwords[0] = (unaligned_uint64_t) v;
}
#else /* BROTLI_GNUC_HAS_ATTRIBUTE(aligned, 2, 7, 0) */
static BROTLI_INLINE uint64_t BrotliUnalignedRead64(const void* p) {
uint64_t v;
memcpy(&v, p, sizeof(uint64_t));
return v;
}

static BROTLI_INLINE void BrotliUnalignedWrite64(void* p, uint64_t v) {
memcpy(p, &v, sizeof(uint64_t));
}
#endif /* BROTLI_GNUC_HAS_ATTRIBUTE(aligned, 2, 7, 0) */
#endif /* BROTLI_64_BITS */
#endif /* BROTLI_ALIGNED_READ */

Expand Down Expand Up @@ -400,7 +421,7 @@ static BROTLI_INLINE void BROTLI_UNALIGNED_STORE64LE(void* p, uint64_t v) {
#define BROTLI_IS_CONSTANT(x) (!!0)
#endif

#if defined(BROTLI_TARGET_ARMV7) || defined(BROTLI_TARGET_ARMV8)
#if defined(BROTLI_TARGET_ARMV7) || defined(BROTLI_TARGET_ARMV8_ANY)
#define BROTLI_HAS_UBFX (!!1)
#else
#define BROTLI_HAS_UBFX (!!0)
Expand All @@ -427,7 +448,7 @@ static BROTLI_INLINE void BrotliDump(const char* f, int l, const char* fn) {
/* TODO: add appropriate icc/sunpro/arm/ibm/ti checks. */
#if (BROTLI_GNUC_VERSION_CHECK(3, 0, 0) || defined(__llvm__)) && \
!defined(BROTLI_BUILD_NO_RBIT)
#if defined(BROTLI_TARGET_ARMV7) || defined(BROTLI_TARGET_ARMV8)
#if defined(BROTLI_TARGET_ARMV7) || defined(BROTLI_TARGET_ARMV8_ANY)
/* TODO: detect ARMv6T2 and enable this code for it. */
static BROTLI_INLINE brotli_reg_t BrotliRBit(brotli_reg_t input) {
brotli_reg_t output;
Expand Down