Adding upstream version 3.3.0+dfsg1.upstream/3.3.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1426 insertions, 0 deletions

diff --git a/winpr/libwinpr/sysinfo/cpufeatures/cpu-features.c b/winpr/libwinpr/sysinfo/cpufeatures/cpu-features.c
new file mode 100644
index 0000000..d43b588
--- /dev/null
+++ b/winpr/libwinpr/sysinfo/cpufeatures/cpu-features.c
@@ -0,0 +1,1426 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/* ChangeLog for this library:
+ *
+ * NDK r10e?: Add MIPS MSA feature.
+ *
+ * NDK r10: Support for 64-bit CPUs (Intel, ARM & MIPS).
+ *
+ * NDK r8d: Add android_setCpu().
+ *
+ * NDK r8c: Add new ARM CPU features: VFPv2, VFP_D32, VFP_FP16,
+ *          VFP_FMA, NEON_FMA, IDIV_ARM, IDIV_THUMB2 and iWMMXt.
+ *
+ *          Rewrite the code to parse /proc/self/auxv instead of
+ *          the "Features" field in /proc/cpuinfo.
+ *
+ *          Dynamically allocate the buffer that hold the content
+ *          of /proc/cpuinfo to deal with newer hardware.
+ *
+ * NDK r7c: Fix CPU count computation. The old method only reported the
+ *           number of _active_ CPUs when the library was initialized,
+ *           which could be less than the real total.
+ *
+ * NDK r5: Handle buggy kernels which report a CPU Architecture number of 7
+ *         for an ARMv6 CPU (see below).
+ *
+ *         Handle kernels that only report 'neon', and not 'vfpv3'
+ *         (VFPv3 is mandated by the ARM architecture is Neon is implemented)
+ *
+ *         Handle kernels that only report 'vfpv3d16', and not 'vfpv3'
+ *
+ *         Fix x86 compilation. Report ANDROID_CPU_FAMILY_X86 in
+ *         android_getCpuFamily().
+ *
+ * NDK r4: Initial release
+ */
+
+#include "cpu-features.h"
+
+#include <dlfcn.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/system_properties.h>
+#include <unistd.h>
+#include <winpr/wtypes.h>
+
+static pthread_once_t g_once;
+static int g_inited;
+static AndroidCpuFamily g_cpuFamily;
+static uint64_t g_cpuFeatures;
+static int g_cpuCount;
+
+#ifdef __arm__
+static uint32_t g_cpuIdArm;
+#endif
+
+static const int android_cpufeatures_debug = 0;
+
+#define D(...)                         \
+	do                                 \
+	{                                  \
+		if (android_cpufeatures_debug) \
+		{                              \
+			printf(__VA_ARGS__);       \
+			fflush(stdout);            \
+		}                              \
+	} while (0)
+
+#ifdef __i386__
+static __inline__ void x86_cpuid(int func, int values[4])
+{
+	int a, b, c, d;
+	/* We need to preserve ebx since we're compiling PIC code */
+	/* this means we can't use "=b" for the second output register */
+	__asm__ __volatile__("push %%ebx\n"
+	                     "cpuid\n"
+	                     "mov %%ebx, %1\n"
+	                     "pop %%ebx\n"
+	                     : "=a"(a), "=r"(b), "=c"(c), "=d"(d)
+	                     : "a"(func));
+	values[0] = a;
+	values[1] = b;
+	values[2] = c;
+	values[3] = d;
+}
+#elif defined(__x86_64__)
+static __inline__ void x86_cpuid(int func, int values[4])
+{
+	int64_t a, b, c, d;
+	/* We need to preserve ebx since we're compiling PIC code */
+	/* this means we can't use "=b" for the second output register */
+	__asm__ __volatile__("push %%rbx\n"
+	                     "cpuid\n"
+	                     "mov %%rbx, %1\n"
+	                     "pop %%rbx\n"
+	                     : "=a"(a), "=r"(b), "=c"(c), "=d"(d)
+	                     : "a"(func));
+	values[0] = a;
+	values[1] = b;
+	values[2] = c;
+	values[3] = d;
+}
+#endif
+
+/* Get the size of a file by reading it until the end. This is needed
+ * because files under /proc do not always return a valid size when
+ * using fseek(0, SEEK_END) + ftell(). Nor can they be mmap()-ed.
+ */
+static int get_file_size(const char* pathname)
+{
+	int fd, result = 0;
+	char buffer[256];
+	fd = open(pathname, O_RDONLY);
+
+	if (fd < 0)
+	{
+		char ebuffer[256] = { 0 };
+		D("Can't open %s: %s\n", pathname, winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
+		return -1;
+	}
+
+	for (;;)
+	{
+		int ret = read(fd, buffer, sizeof buffer);
+
+		if (ret < 0)
+		{
+			char ebuffer[256] = { 0 };
+			if (errno == EINTR)
+				continue;
+
+			D("Error while reading %s: %s\n", pathname,
+			  winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
+			break;
+		}
+
+		if (ret == 0)
+			break;
+
+		result += ret;
+	}
+
+	close(fd);
+	return result;
+}
+
+/* Read the content of /proc/cpuinfo into a user-provided buffer.
+ * Return the length of the data, or -1 on error. Does *not*
+ * zero-terminate the content. Will not read more
+ * than 'buffsize' bytes.
+ */
+static int read_file(const char* pathname, char* buffer, size_t buffsize)
+{
+	int fd, count;
+	fd = open(pathname, O_RDONLY);
+
+	if (fd < 0)
+	{
+		char ebuffer[256] = { 0 };
+		D("Could not open %s: %s\n", pathname, winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
+		return -1;
+	}
+
+	count = 0;
+
+	while (count < (int)buffsize)
+	{
+		int ret = read(fd, buffer + count, buffsize - count);
+
+		if (ret < 0)
+		{
+			char ebuffer[256] = { 0 };
+			if (errno == EINTR)
+				continue;
+
+			D("Error while reading from %s: %s\n", pathname,
+			  winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
+
+			if (count == 0)
+				count = -1;
+
+			break;
+		}
+
+		if (ret == 0)
+			break;
+
+		count += ret;
+	}
+
+	close(fd);
+	return count;
+}
+
+#ifdef __arm__
+/* Extract the content of a the first occurence of a given field in
+ * the content of /proc/cpuinfo and return it as a heap-allocated
+ * string that must be freed by the caller.
+ *
+ * Return NULL if not found
+ */
+static char* extract_cpuinfo_field(const char* buffer, int buflen, const char* field)
+{
+	int fieldlen = strlen(field);
+	const char* bufend = buffer + buflen;
+	char* result = NULL;
+	int len;
+	const char *p, *q;
+	/* Look for first field occurence, and ensures it starts the line. */
+	p = buffer;
+
+	for (;;)
+	{
+		p = memmem(p, bufend - p, field, fieldlen);
+
+		if (p == NULL)
+			goto EXIT;
+
+		if (p == buffer || p[-1] == '\n')
+			break;
+
+		p += fieldlen;
+	}
+
+	/* Skip to the first column followed by a space */
+	p += fieldlen;
+	p = memchr(p, ':', bufend - p);
+
+	if (p == NULL || p[1] != ' ')
+		goto EXIT;
+
+	/* Find the end of the line */
+	p += 2;
+	q = memchr(p, '\n', bufend - p);
+
+	if (q == NULL)
+		q = bufend;
+
+	/* Copy the line into a heap-allocated buffer */
+	len = q - p;
+	result = malloc(len + 1);
+
+	if (result == NULL)
+		goto EXIT;
+
+	memcpy(result, p, len);
+	result[len] = '\0';
+EXIT:
+	return result;
+}
+
+/* Checks that a space-separated list of items contains one given 'item'.
+ * Returns 1 if found, 0 otherwise.
+ */
+static int has_list_item(const char* list, const char* item)
+{
+	const char* p = list;
+	int itemlen = strlen(item);
+
+	if (list == NULL)
+		return 0;
+
+	while (*p)
+	{
+		const char* q;
+
+		/* skip spaces */
+		while (*p == ' ' || *p == '\t')
+			p++;
+
+		/* find end of current list item */
+		q = p;
+
+		while (*q && *q != ' ' && *q != '\t')
+			q++;
+
+		if (itemlen == q - p && !memcmp(p, item, itemlen))
+			return 1;
+
+		/* skip to next item */
+		p = q;
+	}
+
+	return 0;
+}
+#endif /* __arm__ */
+
+/* Parse a number starting from 'input', but not going further
+ * than 'limit'. Return the value into '*result'.
+ *
+ * NOTE: Does not skip over leading spaces, or deal with sign characters.
+ * NOTE: Ignores overflows.
+ *
+ * The function returns NULL in case of error (bad format), or the new
+ * position after the decimal number in case of success (which will always
+ * be <= 'limit').
+ */
+static const char* parse_number(const char* input, const char* limit, int base, int* result)
+{
+	const char* p = input;
+	int val = 0;
+
+	while (p < limit)
+	{
+		int d = (*p - '0');
+
+		if ((unsigned)d >= 10U)
+		{
+			d = (*p - 'a');
+
+			if ((unsigned)d >= 6U)
+				d = (*p - 'A');
+
+			if ((unsigned)d >= 6U)
+				break;
+
+			d += 10;
+		}
+
+		if (d >= base)
+			break;
+
+		val = val * base + d;
+		p++;
+	}
+
+	if (p == input)
+		return NULL;
+
+	*result = val;
+	return p;
+}
+
+static const char* parse_decimal(const char* input, const char* limit, int* result)
+{
+	return parse_number(input, limit, 10, result);
+}
+
+#ifdef __arm__
+static const char* parse_hexadecimal(const char* input, const char* limit, int* result)
+{
+	return parse_number(input, limit, 16, result);
+}
+#endif /* __arm__ */
+
+/* This small data type is used to represent a CPU list / mask, as read
+ * from sysfs on Linux. See http://www.kernel.org/doc/Documentation/cputopology.txt
+ *
+ * For now, we don't expect more than 32 cores on mobile devices, so keep
+ * everything simple.
+ */
+typedef struct
+{
+	uint32_t mask;
+} CpuList;
+
+static __inline__ void cpulist_init(CpuList* list)
+{
+	list->mask = 0;
+}
+
+static __inline__ void cpulist_and(CpuList* list1, CpuList* list2)
+{
+	list1->mask &= list2->mask;
+}
+
+static __inline__ void cpulist_set(CpuList* list, int index)
+{
+	if ((unsigned)index < 32)
+	{
+		list->mask |= (uint32_t)(1U << index);
+	}
+}
+
+static __inline__ int cpulist_count(CpuList* list)
+{
+	return __builtin_popcount(list->mask);
+}
+
+/* Parse a textual list of cpus and store the result inside a CpuList object.
+ * Input format is the following:
+ * - comma-separated list of items (no spaces)
+ * - each item is either a single decimal number (cpu index), or a range made
+ *   of two numbers separated by a single dash (-). Ranges are inclusive.
+ *
+ * Examples:   0
+ *             2,4-127,128-143
+ *             0-1
+ */
+static void cpulist_parse(CpuList* list, const char* line, int line_len)
+{
+	const char* p = line;
+	const char* end = p + line_len;
+	const char* q;
+
+	/* NOTE: the input line coming from sysfs typically contains a
+	 * trailing newline, so take care of it in the code below
+	 */
+	while (p < end && *p != '\n')
+	{
+		int start_value = 0;
+		int end_value = 0;
+		/* Find the end of current item, and put it into 'q' */
+		q = memchr(p, ',', end - p);
+
+		if (q == NULL)
+		{
+			q = end;
+		}
+
+		/* Get first value */
+		p = parse_decimal(p, q, &start_value);
+
+		if (p == NULL)
+			goto BAD_FORMAT;
+
+		end_value = start_value;
+
+		/* If we're not at the end of the item, expect a dash and
+		 * and integer; extract end value.
+		 */
+		if (p < q && *p == '-')
+		{
+			p = parse_decimal(p + 1, q, &end_value);
+
+			if (p == NULL)
+				goto BAD_FORMAT;
+		}
+
+		/* Set bits CPU list bits */
+		for (int val = start_value; val <= end_value; val++)
+		{
+			cpulist_set(list, val);
+		}
+
+		/* Jump to next item */
+		p = q;
+
+		if (p < end)
+			p++;
+	}
+
+BAD_FORMAT:;
+}
+
+/* Read a CPU list from one sysfs file */
+static void cpulist_read_from(CpuList* list, const char* filename)
+{
+	char file[64];
+	int filelen;
+	cpulist_init(list);
+	filelen = read_file(filename, file, sizeof file);
+
+	if (filelen < 0)
+	{
+		char ebuffer[256] = { 0 };
+		D("Could not read %s: %s\n", filename, winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
+		return;
+	}
+
+	cpulist_parse(list, file, filelen);
+}
+#if defined(__aarch64__)
+// see <uapi/asm/hwcap.h> kernel header
+#define HWCAP_FP (1 << 0)
+#define HWCAP_ASIMD (1 << 1)
+#define HWCAP_AES (1 << 3)
+#define HWCAP_PMULL (1 << 4)
+#define HWCAP_SHA1 (1 << 5)
+#define HWCAP_SHA2 (1 << 6)
+#define HWCAP_CRC32 (1 << 7)
+#endif
+
+#if defined(__arm__)
+
+// See <asm/hwcap.h> kernel header.
+#define HWCAP_VFP (1 << 6)
+#define HWCAP_IWMMXT (1 << 9)
+#define HWCAP_NEON (1 << 12)
+#define HWCAP_VFPv3 (1 << 13)
+#define HWCAP_VFPv3D16 (1 << 14)
+#define HWCAP_VFPv4 (1 << 16)
+#define HWCAP_IDIVA (1 << 17)
+#define HWCAP_IDIVT (1 << 18)
+
+// see <uapi/asm/hwcap.h> kernel header
+#define HWCAP2_AES (1 << 0)
+#define HWCAP2_PMULL (1 << 1)
+#define HWCAP2_SHA1 (1 << 2)
+#define HWCAP2_SHA2 (1 << 3)
+#define HWCAP2_CRC32 (1 << 4)
+
+// This is the list of 32-bit ARMv7 optional features that are _always_
+// supported by ARMv8 CPUs, as mandated by the ARM Architecture Reference
+// Manual.
+#define HWCAP_SET_FOR_ARMV8 \
+	(HWCAP_VFP | HWCAP_NEON | HWCAP_VFPv3 | HWCAP_VFPv4 | HWCAP_IDIVA | HWCAP_IDIVT)
+#endif
+
+#if defined(__mips__)
+// see <uapi/asm/hwcap.h> kernel header
+#define HWCAP_MIPS_R6 (1 << 0)
+#define HWCAP_MIPS_MSA (1 << 1)
+#endif
+
+#if defined(__arm__) || defined(__aarch64__) || defined(__mips__)
+
+#define AT_HWCAP 16
+#define AT_HWCAP2 26
+
+// Probe the system's C library for a 'getauxval' function and call it if
+// it exits, or return 0 for failure. This function is available since API
+// level 20.
+//
+// This code does *NOT* check for '__ANDROID_API__ >= 20' to support the
+// edge case where some NDK developers use headers for a platform that is
+// newer than the one really targetted by their application.
+// This is typically done to use newer native APIs only when running on more
+// recent Android versions, and requires careful symbol management.
+//
+// Note that getauxval() can't really be re-implemented here, because
+// its implementation does not parse /proc/self/auxv. Instead it depends
+// on values  that are passed by the kernel at process-init time to the
+// C runtime initialization layer.
+static uint32_t get_elf_hwcap_from_getauxval(int hwcap_type)
+{
+	typedef unsigned long getauxval_func_t(unsigned long);
+	dlerror();
+	void* libc_handle = dlopen("libc.so", RTLD_NOW);
+
+	if (!libc_handle)
+	{
+		D("Could not dlopen() C library: %s\n", dlerror());
+		return 0;
+	}
+
+	uint32_t ret = 0;
+	getauxval_func_t* func = (getauxval_func_t*)dlsym(libc_handle, "getauxval");
+
+	if (!func)
+	{
+		D("Could not find getauxval() in C library\n");
+	}
+	else
+	{
+		// Note: getauxval() returns 0 on failure. Doesn't touch errno.
+		ret = (uint32_t)(*func)(hwcap_type);
+	}
+
+	dlclose(libc_handle);
+	return ret;
+}
+#endif
+
+#if defined(__arm__)
+// Parse /proc/self/auxv to extract the ELF HW capabilities bitmap for the
+// current CPU. Note that this file is not accessible from regular
+// application processes on some Android platform releases.
+// On success, return new ELF hwcaps, or 0 on failure.
+static uint32_t get_elf_hwcap_from_proc_self_auxv(void)
+{
+	const char filepath[] = "/proc/self/auxv";
+	int fd = TEMP_FAILURE_RETRY(open(filepath, O_RDONLY));
+
+	if (fd < 0)
+	{
+		char ebuffer[256] = { 0 };
+		D("Could not open %s: %s\n", filepath, winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
+		return 0;
+	}
+
+	struct
+	{
+		uint32_t tag;
+		uint32_t value;
+	} entry;
+
+	uint32_t result = 0;
+
+	for (;;)
+	{
+		int ret = TEMP_FAILURE_RETRY(read(fd, (char*)&entry, sizeof entry));
+
+		if (ret < 0)
+		{
+			char ebuffer[256] = { 0 };
+			D("Error while reading %s: %s\n", filepath,
+			  winpr_strerror(errno, ebuffer, sizeof(ebuffer)));
+			break;
+		}
+
+		// Detect end of list.
+		if (ret == 0 || (entry.tag == 0 && entry.value == 0))
+			break;
+
+		if (entry.tag == AT_HWCAP)
+		{
+			result = entry.value;
+			break;
+		}
+	}
+
+	close(fd);
+	return result;
+}
+
+/* Compute the ELF HWCAP flags from the content of /proc/cpuinfo.
+ * This works by parsing the 'Features' line, which lists which optional
+ * features the device's CPU supports, on top of its reference
+ * architecture.
+ */
+static uint32_t get_elf_hwcap_from_proc_cpuinfo(const char* cpuinfo, int cpuinfo_len)
+{
+	uint32_t hwcaps = 0;
+	long architecture = 0;
+	char* cpuArch = extract_cpuinfo_field(cpuinfo, cpuinfo_len, "CPU architecture");
+
+	if (cpuArch)
+	{
+		architecture = strtol(cpuArch, NULL, 10);
+		free(cpuArch);
+
+		if (architecture >= 8L)
+		{
+			// This is a 32-bit ARM binary running on a 64-bit ARM64 kernel.
+			// The 'Features' line only lists the optional features that the
+			// device's CPU supports, compared to its reference architecture
+			// which are of no use for this process.
+			D("Faking 32-bit ARM HWCaps on ARMv%ld CPU\n", architecture);
+			return HWCAP_SET_FOR_ARMV8;
+		}
+	}
+
+	char* cpuFeatures = extract_cpuinfo_field(cpuinfo, cpuinfo_len, "Features");
+
+	if (cpuFeatures != NULL)
+	{
+		D("Found cpuFeatures = '%s'\n", cpuFeatures);
+
+		if (has_list_item(cpuFeatures, "vfp"))
+			hwcaps |= HWCAP_VFP;
+
+		if (has_list_item(cpuFeatures, "vfpv3"))
+			hwcaps |= HWCAP_VFPv3;
+
+		if (has_list_item(cpuFeatures, "vfpv3d16"))
+			hwcaps |= HWCAP_VFPv3D16;
+
+		if (has_list_item(cpuFeatures, "vfpv4"))
+			hwcaps |= HWCAP_VFPv4;
+
+		if (has_list_item(cpuFeatures, "neon"))
+			hwcaps |= HWCAP_NEON;
+
+		if (has_list_item(cpuFeatures, "idiva"))
+			hwcaps |= HWCAP_IDIVA;
+
+		if (has_list_item(cpuFeatures, "idivt"))
+			hwcaps |= HWCAP_IDIVT;
+
+		if (has_list_item(cpuFeatures, "idiv"))
+			hwcaps |= HWCAP_IDIVA | HWCAP_IDIVT;
+
+		if (has_list_item(cpuFeatures, "iwmmxt"))
+			hwcaps |= HWCAP_IWMMXT;
+
+		free(cpuFeatures);
+	}
+
+	return hwcaps;
+}
+#endif /* __arm__ */
+
+/* Return the number of cpus present on a given device.
+ *
+ * To handle all weird kernel configurations, we need to compute the
+ * intersection of the 'present' and 'possible' CPU lists and count
+ * the result.
+ */
+static int get_cpu_count(void)
+{
+	CpuList cpus_present[1];
+	CpuList cpus_possible[1];
+	cpulist_read_from(cpus_present, "/sys/devices/system/cpu/present");
+	cpulist_read_from(cpus_possible, "/sys/devices/system/cpu/possible");
+	/* Compute the intersection of both sets to get the actual number of
+	 * CPU cores that can be used on this device by the kernel.
+	 */
+	cpulist_and(cpus_present, cpus_possible);
+	return cpulist_count(cpus_present);
+}
+
+static void android_cpuInitFamily(void)
+{
+#if defined(__arm__)
+	g_cpuFamily = ANDROID_CPU_FAMILY_ARM;
+#elif defined(__i386__)
+	g_cpuFamily = ANDROID_CPU_FAMILY_X86;
+#elif defined(__mips64)
+	/* Needs to be before __mips__ since the compiler defines both */
+	g_cpuFamily = ANDROID_CPU_FAMILY_MIPS64;
+#elif defined(__mips__)
+	g_cpuFamily = ANDROID_CPU_FAMILY_MIPS;
+#elif defined(__aarch64__)
+	g_cpuFamily = ANDROID_CPU_FAMILY_ARM64;
+#elif defined(__x86_64__)
+	g_cpuFamily = ANDROID_CPU_FAMILY_X86_64;
+#else
+	g_cpuFamily = ANDROID_CPU_FAMILY_UNKNOWN;
+#endif
+}
+
+static void android_cpuInit(void)
+{
+	char* cpuinfo = NULL;
+	int cpuinfo_len;
+	android_cpuInitFamily();
+	g_cpuFeatures = 0;
+	g_cpuCount = 1;
+	g_inited = 1;
+	cpuinfo_len = get_file_size("/proc/cpuinfo");
+
+	if (cpuinfo_len < 0)
+	{
+		D("cpuinfo_len cannot be computed!");
+		return;
+	}
+
+	cpuinfo = malloc(cpuinfo_len);
+
+	if (cpuinfo == NULL)
+	{
+		D("cpuinfo buffer could not be allocated");
+		return;
+	}
+
+	cpuinfo_len = read_file("/proc/cpuinfo", cpuinfo, cpuinfo_len);
+	D("cpuinfo_len is (%d):\n%.*s\n", cpuinfo_len, cpuinfo_len >= 0 ? cpuinfo_len : 0, cpuinfo);
+
+	if (cpuinfo_len < 0) /* should not happen */
+	{
+		free(cpuinfo);
+		return;
+	}
+
+	/* Count the CPU cores, the value may be 0 for single-core CPUs */
+	g_cpuCount = get_cpu_count();
+
+	if (g_cpuCount == 0)
+	{
+		g_cpuCount = 1;
+	}
+
+	D("found cpuCount = %d\n", g_cpuCount);
+#ifdef __arm__
+	{
+		/* Extract architecture from the "CPU Architecture" field.
+		 * The list is well-known, unlike the the output of
+		 * the 'Processor' field which can vary greatly.
+		 *
+		 * See the definition of the 'proc_arch' array in
+		 * $KERNEL/arch/arm/kernel/setup.c and the 'c_show' function in
+		 * same file.
+		 */
+		char* cpuArch = extract_cpuinfo_field(cpuinfo, cpuinfo_len, "CPU architecture");
+
+		if (cpuArch != NULL)
+		{
+			char* end;
+			long archNumber;
+			int hasARMv7 = 0;
+			D("found cpuArch = '%s'\n", cpuArch);
+			/* read the initial decimal number, ignore the rest */
+			archNumber = strtol(cpuArch, &end, 10);
+
+			/* Note that ARMv8 is upwards compatible with ARMv7. */
+			if (end > cpuArch && archNumber >= 7)
+			{
+				hasARMv7 = 1;
+			}
+
+			/* Unfortunately, it seems that certain ARMv6-based CPUs
+			 * report an incorrect architecture number of 7!
+			 *
+			 * See http://code.google.com/p/android/issues/detail?id=10812
+			 *
+			 * We try to correct this by looking at the 'elf_format'
+			 * field reported by the 'Processor' field, which is of the
+			 * form of "(v7l)" for an ARMv7-based CPU, and "(v6l)" for
+			 * an ARMv6-one.
+			 */
+			if (hasARMv7)
+			{
+				char* cpuProc = extract_cpuinfo_field(cpuinfo, cpuinfo_len, "Processor");
+
+				if (cpuProc != NULL)
+				{
+					D("found cpuProc = '%s'\n", cpuProc);
+
+					if (has_list_item(cpuProc, "(v6l)"))
+					{
+						D("CPU processor and architecture mismatch!!\n");
+						hasARMv7 = 0;
+					}
+
+					free(cpuProc);
+				}
+			}
+
+			if (hasARMv7)
+			{
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_ARMv7;
+			}
+
+			/* The LDREX / STREX instructions are available from ARMv6 */
+			if (archNumber >= 6)
+			{
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_LDREX_STREX;
+			}
+
+			free(cpuArch);
+		}
+
+		/* Extract the list of CPU features from ELF hwcaps */
+		uint32_t hwcaps = 0;
+		hwcaps = get_elf_hwcap_from_getauxval(AT_HWCAP);
+
+		if (!hwcaps)
+		{
+			D("Parsing /proc/self/auxv to extract ELF hwcaps!\n");
+			hwcaps = get_elf_hwcap_from_proc_self_auxv();
+		}
+
+		if (!hwcaps)
+		{
+			// Parsing /proc/self/auxv will fail from regular application
+			// processes on some Android platform versions, when this happens
+			// parse proc/cpuinfo instead.
+			D("Parsing /proc/cpuinfo to extract ELF hwcaps!\n");
+			hwcaps = get_elf_hwcap_from_proc_cpuinfo(cpuinfo, cpuinfo_len);
+		}
+
+		if (hwcaps != 0)
+		{
+			int has_vfp = (hwcaps & HWCAP_VFP);
+			int has_vfpv3 = (hwcaps & HWCAP_VFPv3);
+			int has_vfpv3d16 = (hwcaps & HWCAP_VFPv3D16);
+			int has_vfpv4 = (hwcaps & HWCAP_VFPv4);
+			int has_neon = (hwcaps & HWCAP_NEON);
+			int has_idiva = (hwcaps & HWCAP_IDIVA);
+			int has_idivt = (hwcaps & HWCAP_IDIVT);
+			int has_iwmmxt = (hwcaps & HWCAP_IWMMXT);
+
+			// The kernel does a poor job at ensuring consistency when
+			// describing CPU features. So lots of guessing is needed.
+
+			// 'vfpv4' implies VFPv3|VFP_FMA|FP16
+			if (has_vfpv4)
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3 | ANDROID_CPU_ARM_FEATURE_VFP_FP16 |
+				                 ANDROID_CPU_ARM_FEATURE_VFP_FMA;
+
+			// 'vfpv3' or 'vfpv3d16' imply VFPv3. Note that unlike GCC,
+			// a value of 'vfpv3' doesn't necessarily mean that the D32
+			// feature is present, so be conservative. All CPUs in the
+			// field that support D32 also support NEON, so this should
+			// not be a problem in practice.
+			if (has_vfpv3 || has_vfpv3d16)
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3;
+
+			// 'vfp' is super ambiguous. Depending on the kernel, it can
+			// either mean VFPv2 or VFPv3. Make it depend on ARMv7.
+			if (has_vfp)
+			{
+				if (g_cpuFeatures & ANDROID_CPU_ARM_FEATURE_ARMv7)
+					g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3;
+				else
+					g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv2;
+			}
+
+			// Neon implies VFPv3|D32, and if vfpv4 is detected, NEON_FMA
+			if (has_neon)
+			{
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3 | ANDROID_CPU_ARM_FEATURE_NEON |
+				                 ANDROID_CPU_ARM_FEATURE_VFP_D32;
+
+				if (has_vfpv4)
+					g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_NEON_FMA;
+			}
+
+			// VFPv3 implies VFPv2 and ARMv7
+			if (g_cpuFeatures & ANDROID_CPU_ARM_FEATURE_VFPv3)
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv2 | ANDROID_CPU_ARM_FEATURE_ARMv7;
+
+			if (has_idiva)
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_IDIV_ARM;
+
+			if (has_idivt)
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_IDIV_THUMB2;
+
+			if (has_iwmmxt)
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_iWMMXt;
+		}
+
+		/* Extract the list of CPU features from ELF hwcaps2 */
+		uint32_t hwcaps2 = 0;
+		hwcaps2 = get_elf_hwcap_from_getauxval(AT_HWCAP2);
+
+		if (hwcaps2 != 0)
+		{
+			int has_aes = (hwcaps2 & HWCAP2_AES);
+			int has_pmull = (hwcaps2 & HWCAP2_PMULL);
+			int has_sha1 = (hwcaps2 & HWCAP2_SHA1);
+			int has_sha2 = (hwcaps2 & HWCAP2_SHA2);
+			int has_crc32 = (hwcaps2 & HWCAP2_CRC32);
+
+			if (has_aes)
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_AES;
+
+			if (has_pmull)
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_PMULL;
+
+			if (has_sha1)
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_SHA1;
+
+			if (has_sha2)
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_SHA2;
+
+			if (has_crc32)
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_CRC32;
+		}
+
+		/* Extract the cpuid value from various fields */
+		// The CPUID value is broken up in several entries in /proc/cpuinfo.
+		// This table is used to rebuild it from the entries.
+		static const struct CpuIdEntry
+		{
+			const char* field;
+			char format;
+			char bit_lshift;
+			char bit_length;
+		} cpu_id_entries[] = {
+			{ "CPU implementer", 'x', 24, 8 },
+			{ "CPU variant", 'x', 20, 4 },
+			{ "CPU part", 'x', 4, 12 },
+			{ "CPU revision", 'd', 0, 4 },
+		};
+		D("Parsing /proc/cpuinfo to recover CPUID\n");
+
+		for (size_t i = 0; i < sizeof(cpu_id_entries) / sizeof(cpu_id_entries[0]); ++i)
+		{
+			const struct CpuIdEntry* entry = &cpu_id_entries[i];
+			char* value = extract_cpuinfo_field(cpuinfo, cpuinfo_len, entry->field);
+
+			if (value == NULL)
+				continue;
+
+			D("field=%s value='%s'\n", entry->field, value);
+			char* value_end = value + strlen(value);
+			int val = 0;
+			const char* start = value;
+			const char* p;
+
+			if (value[0] == '0' && (value[1] == 'x' || value[1] == 'X'))
+			{
+				start += 2;
+				p = parse_hexadecimal(start, value_end, &val);
+			}
+			else if (entry->format == 'x')
+				p = parse_hexadecimal(value, value_end, &val);
+			else
+				p = parse_decimal(value, value_end, &val);
+
+			if (p > (const char*)start)
+			{
+				val &= ((1 << entry->bit_length) - 1);
+				val <<= entry->bit_lshift;
+				g_cpuIdArm |= (uint32_t)val;
+			}
+
+			free(value);
+		}
+
+		// Handle kernel configuration bugs that prevent the correct
+		// reporting of CPU features.
+		static const struct CpuFix
+		{
+			uint32_t cpuid;
+			uint64_t or_flags;
+		} cpu_fixes[] = {
+			/* The Nexus 4 (Qualcomm Krait) kernel configuration
+			 * forgets to report IDIV support. */
+			{ 0x510006f2, ANDROID_CPU_ARM_FEATURE_IDIV_ARM | ANDROID_CPU_ARM_FEATURE_IDIV_THUMB2 },
+			{ 0x510006f3, ANDROID_CPU_ARM_FEATURE_IDIV_ARM | ANDROID_CPU_ARM_FEATURE_IDIV_THUMB2 },
+		};
+
+		for (size_t n = 0; n < sizeof(cpu_fixes) / sizeof(cpu_fixes[0]); ++n)
+		{
+			const struct CpuFix* entry = &cpu_fixes[n];
+
+			if (g_cpuIdArm == entry->cpuid)
+				g_cpuFeatures |= entry->or_flags;
+		}
+
+		// Special case: The emulator-specific Android 4.2 kernel fails
+		// to report support for the 32-bit ARM IDIV instruction.
+		// Technically, this is a feature of the virtual CPU implemented
+		// by the emulator. Note that it could also support Thumb IDIV
+		// in the future, and this will have to be slightly updated.
+		char* hardware = extract_cpuinfo_field(cpuinfo, cpuinfo_len, "Hardware");
+
+		if (hardware)
+		{
+			if (!strcmp(hardware, "Goldfish") && g_cpuIdArm == 0x4100c080 &&
+			    (g_cpuFamily & ANDROID_CPU_ARM_FEATURE_ARMv7) != 0)
+			{
+				g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_IDIV_ARM;
+			}
+
+			free(hardware);
+		}
+	}
+#endif /* __arm__ */
+#ifdef __aarch64__
+	{
+		/* Extract the list of CPU features from ELF hwcaps */
+		uint32_t hwcaps = 0;
+		hwcaps = get_elf_hwcap_from_getauxval(AT_HWCAP);
+
+		if (hwcaps != 0)
+		{
+			int has_fp = (hwcaps & HWCAP_FP);
+			int has_asimd = (hwcaps & HWCAP_ASIMD);
+			int has_aes = (hwcaps & HWCAP_AES);
+			int has_pmull = (hwcaps & HWCAP_PMULL);
+			int has_sha1 = (hwcaps & HWCAP_SHA1);
+			int has_sha2 = (hwcaps & HWCAP_SHA2);
+			int has_crc32 = (hwcaps & HWCAP_CRC32);
+
+			if (has_fp == 0)
+			{
+				D("ERROR: Floating-point unit missing, but is required by Android on AArch64 "
+				  "CPUs\n");
+			}
+
+			if (has_asimd == 0)
+			{
+				D("ERROR: ASIMD unit missing, but is required by Android on AArch64 CPUs\n");
+			}
+
+			if (has_fp)
+				g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_FP;
+
+			if (has_asimd)
+				g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_ASIMD;
+
+			if (has_aes)
+				g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_AES;
+
+			if (has_pmull)
+				g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_PMULL;
+
+			if (has_sha1)
+				g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_SHA1;
+
+			if (has_sha2)
+				g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_SHA2;
+
+			if (has_crc32)
+				g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_CRC32;
+		}
+	}
+#endif /* __aarch64__ */
+#if defined(__i386__) || defined(__x86_64__)
+	int regs[4];
+	/* According to http://en.wikipedia.org/wiki/CPUID */
+#define VENDOR_INTEL_b 0x756e6547
+#define VENDOR_INTEL_c 0x6c65746e
+#define VENDOR_INTEL_d 0x49656e69
+	x86_cpuid(0, regs);
+	int vendorIsIntel =
+	    (regs[1] == VENDOR_INTEL_b && regs[2] == VENDOR_INTEL_c && regs[3] == VENDOR_INTEL_d);
+	x86_cpuid(1, regs);
+
+	if ((regs[2] & (1 << 9)) != 0)
+	{
+		g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_SSSE3;
+	}
+
+	if ((regs[2] & (1 << 23)) != 0)
+	{
+		g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_POPCNT;
+	}
+
+	if ((regs[2] & (1 << 19)) != 0)
+	{
+		g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_SSE4_1;
+	}
+
+	if ((regs[2] & (1 << 20)) != 0)
+	{
+		g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_SSE4_2;
+	}
+
+	if (vendorIsIntel && (regs[2] & (1 << 22)) != 0)
+	{
+		g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_MOVBE;
+	}
+
+	if ((regs[2] & (1 << 25)) != 0)
+	{
+		g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_AES_NI;
+	}
+
+	if ((regs[2] & (1 << 28)) != 0)
+	{
+		g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_AVX;
+	}
+
+	if ((regs[2] & (1 << 30)) != 0)
+	{
+		g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_RDRAND;
+	}
+
+	x86_cpuid(7, regs);
+
+	if ((regs[1] & (1 << 5)) != 0)
+	{
+		g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_AVX2;
+	}
+
+	if ((regs[1] & (1 << 29)) != 0)
+	{
+		g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_SHA_NI;
+	}
+
+#endif
+#if defined(__mips__)
+	{
+		/* MIPS and MIPS64 */
+		/* Extract the list of CPU features from ELF hwcaps */
+		uint32_t hwcaps = 0;
+		hwcaps = get_elf_hwcap_from_getauxval(AT_HWCAP);
+
+		if (hwcaps != 0)
+		{
+			int has_r6 = (hwcaps & HWCAP_MIPS_R6);
+			int has_msa = (hwcaps & HWCAP_MIPS_MSA);
+
+			if (has_r6)
+				g_cpuFeatures |= ANDROID_CPU_MIPS_FEATURE_R6;
+
+			if (has_msa)
+				g_cpuFeatures |= ANDROID_CPU_MIPS_FEATURE_MSA;
+		}
+	}
+#endif /* __mips__ */
+	free(cpuinfo);
+}
+
+AndroidCpuFamily android_getCpuFamily(void)
+{
+	pthread_once(&g_once, android_cpuInit);
+	return g_cpuFamily;
+}
+
+uint64_t android_getCpuFeatures(void)
+{
+	pthread_once(&g_once, android_cpuInit);
+	return g_cpuFeatures;
+}
+
+int android_getCpuCount(void)
+{
+	pthread_once(&g_once, android_cpuInit);
+	return g_cpuCount;
+}
+
+static void android_cpuInitDummy(void)
+{
+	g_inited = 1;
+}
+
+int android_setCpu(int cpu_count, uint64_t cpu_features)
+{
+	/* Fail if the library was already initialized. */
+	if (g_inited)
+		return 0;
+
+	android_cpuInitFamily();
+	g_cpuCount = (cpu_count <= 0 ? 1 : cpu_count);
+	g_cpuFeatures = cpu_features;
+	pthread_once(&g_once, android_cpuInitDummy);
+	return 1;
+}
+
+#ifdef __arm__
+uint32_t android_getCpuIdArm(void)
+{
+	pthread_once(&g_once, android_cpuInit);
+	return g_cpuIdArm;
+}
+
+int android_setCpuArm(int cpu_count, uint64_t cpu_features, uint32_t cpu_id)
+{
+	if (!android_setCpu(cpu_count, cpu_features))
+		return 0;
+
+	g_cpuIdArm = cpu_id;
+	return 1;
+}
+#endif /* __arm__ */
+
+/*
+ * Technical note: Making sense of ARM's FPU architecture versions.
+ *
+ * FPA was ARM's first attempt at an FPU architecture. There is no Android
+ * device that actually uses it since this technology was already obsolete
+ * when the project started. If you see references to FPA instructions
+ * somewhere, you can be sure that this doesn't apply to Android at all.
+ *
+ * FPA was followed by "VFP", soon renamed "VFPv1" due to the emergence of
+ * new versions / additions to it. ARM considers this obsolete right now,
+ * and no known Android device implements it either.
+ *
+ * VFPv2 added a few instructions to VFPv1, and is an *optional* extension
+ * supported by some ARMv5TE, ARMv6 and ARMv6T2 CPUs. Note that a device
+ * supporting the 'armeabi' ABI doesn't necessarily support these.
+ *
+ * VFPv3-D16 adds a few instructions on top of VFPv2 and is typically used
+ * on ARMv7-A CPUs which implement a FPU. Note that it is also mandated
+ * by the Android 'armeabi-v7a' ABI. The -D16 suffix in its name means
+ * that it provides 16 double-precision FPU registers (d0-d15) and 32
+ * single-precision ones (s0-s31) which happen to be mapped to the same
+ * register banks.
+ *
+ * VFPv3-D32 is the name of an extension to VFPv3-D16 that provides 16
+ * additional double precision registers (d16-d31). Note that there are
+ * still only 32 single precision registers.
+ *
+ * VFPv3xD is a *subset* of VFPv3-D16 that only provides single-precision
+ * registers. It is only used on ARMv7-M (i.e. on micro-controllers) which
+ * are not supported by Android. Note that it is not compatible with VFPv2.
+ *
+ * NOTE: The term 'VFPv3' usually designate either VFPv3-D16 or VFPv3-D32
+ *       depending on context. For example GCC uses it for VFPv3-D32, but
+ *       the Linux kernel code uses it for VFPv3-D16 (especially in
+ *       /proc/cpuinfo). Always try to use the full designation when
+ *       possible.
+ *
+ * NEON, a.k.a. "ARM Advanced SIMD" is an extension that provides
+ * instructions to perform parallel computations on vectors of 8, 16,
+ * 32, 64 and 128 bit quantities. NEON requires VFPv32-D32 since all
+ * NEON registers are also mapped to the same register banks.
+ *
+ * VFPv4-D16, adds a few instructions on top of VFPv3-D16 in order to
+ * perform fused multiply-accumulate on VFP registers, as well as
+ * half-precision (16-bit) conversion operations.
+ *
+ * VFPv4-D32 is VFPv4-D16 with 32, instead of 16, FPU double precision
+ * registers.
+ *
+ * VPFv4-NEON is VFPv4-D32 with NEON instructions. It also adds fused
+ * multiply-accumulate instructions that work on the NEON registers.
+ *
+ * NOTE: Similarly, "VFPv4" might either reference VFPv4-D16 or VFPv4-D32
+ *       depending on context.
+ *
+ * The following information was determined by scanning the binutils-2.22
+ * sources:
+ *
+ * Basic VFP instruction subsets:
+ *
+ * #define FPU_VFP_EXT_V1xD 0x08000000     // Base VFP instruction set.
+ * #define FPU_VFP_EXT_V1   0x04000000     // Double-precision insns.
+ * #define FPU_VFP_EXT_V2   0x02000000     // ARM10E VFPr1.
+ * #define FPU_VFP_EXT_V3xD 0x01000000     // VFPv3 single-precision.
+ * #define FPU_VFP_EXT_V3   0x00800000     // VFPv3 double-precision.
+ * #define FPU_NEON_EXT_V1  0x00400000     // Neon (SIMD) insns.
+ * #define FPU_VFP_EXT_D32  0x00200000     // Registers D16-D31.
+ * #define FPU_VFP_EXT_FP16 0x00100000     // Half-precision extensions.
+ * #define FPU_NEON_EXT_FMA 0x00080000     // Neon fused multiply-add
+ * #define FPU_VFP_EXT_FMA  0x00040000     // VFP fused multiply-add
+ *
+ * FPU types (excluding NEON)
+ *
+ * FPU_VFP_V1xD (EXT_V1xD)
+ *    |
+ *    +--------------------------+
+ *    |                          |
+ * FPU_VFP_V1 (+EXT_V1)       FPU_VFP_V3xD (+EXT_V2+EXT_V3xD)
+ *    |                          |
+ *    |                          |
+ * FPU_VFP_V2 (+EXT_V2)       FPU_VFP_V4_SP_D16 (+EXT_FP16+EXT_FMA)
+ *    |
+ * FPU_VFP_V3D16 (+EXT_Vx3D+EXT_V3)
+ *    |
+ *    +--------------------------+
+ *    |                          |
+ * FPU_VFP_V3 (+EXT_D32)     FPU_VFP_V4D16 (+EXT_FP16+EXT_FMA)
+ *    |                          |
+ *    |                      FPU_VFP_V4 (+EXT_D32)
+ *    |
+ * FPU_VFP_HARD (+EXT_FMA+NEON_EXT_FMA)
+ *
+ * VFP architectures:
+ *
+ * ARCH_VFP_V1xD  (EXT_V1xD)
+ *   |
+ *   +------------------+
+ *   |                  |
+ *   |             ARCH_VFP_V3xD (+EXT_V2+EXT_V3xD)
+ *   |                  |
+ *   |             ARCH_VFP_V3xD_FP16 (+EXT_FP16)
+ *   |                  |
+ *   |             ARCH_VFP_V4_SP_D16 (+EXT_FMA)
+ *   |
+ * ARCH_VFP_V1 (+EXT_V1)
+ *   |
+ * ARCH_VFP_V2 (+EXT_V2)
+ *   |
+ * ARCH_VFP_V3D16 (+EXT_V3xD+EXT_V3)
+ *   |
+ *   +-------------------+
+ *   |                   |
+ *   |         ARCH_VFP_V3D16_FP16  (+EXT_FP16)
+ *   |
+ *   +-------------------+
+ *   |                   |
+ *   |         ARCH_VFP_V4_D16 (+EXT_FP16+EXT_FMA)
+ *   |                   |
+ *   |         ARCH_VFP_V4 (+EXT_D32)
+ *   |                   |
+ *   |         ARCH_NEON_VFP_V4 (+EXT_NEON+EXT_NEON_FMA)
+ *   |
+ * ARCH_VFP_V3 (+EXT_D32)
+ *   |
+ *   +-------------------+
+ *   |                   |
+ *   |         ARCH_VFP_V3_FP16 (+EXT_FP16)
+ *   |
+ * ARCH_VFP_V3_PLUS_NEON_V1 (+EXT_NEON)
+ *   |
+ * ARCH_NEON_FP16 (+EXT_FP16)
+ *
+ * -fpu=<name> values and their correspondance with FPU architectures above:
+ *
+ *   {"vfp",               FPU_ARCH_VFP_V2},
+ *   {"vfp9",              FPU_ARCH_VFP_V2},
+ *   {"vfp3",              FPU_ARCH_VFP_V3}, // For backwards compatbility.
+ *   {"vfp10",             FPU_ARCH_VFP_V2},
+ *   {"vfp10-r0",          FPU_ARCH_VFP_V1},
+ *   {"vfpxd",             FPU_ARCH_VFP_V1xD},
+ *   {"vfpv2",             FPU_ARCH_VFP_V2},
+ *   {"vfpv3",             FPU_ARCH_VFP_V3},
+ *   {"vfpv3-fp16",        FPU_ARCH_VFP_V3_FP16},
+ *   {"vfpv3-d16",         FPU_ARCH_VFP_V3D16},
+ *   {"vfpv3-d16-fp16",    FPU_ARCH_VFP_V3D16_FP16},
+ *   {"vfpv3xd",           FPU_ARCH_VFP_V3xD},
+ *   {"vfpv3xd-fp16",      FPU_ARCH_VFP_V3xD_FP16},
+ *   {"neon",              FPU_ARCH_VFP_V3_PLUS_NEON_V1},
+ *   {"neon-fp16",         FPU_ARCH_NEON_FP16},
+ *   {"vfpv4",             FPU_ARCH_VFP_V4},
+ *   {"vfpv4-d16",         FPU_ARCH_VFP_V4D16},
+ *   {"fpv4-sp-d16",       FPU_ARCH_VFP_V4_SP_D16},
+ *   {"neon-vfpv4",        FPU_ARCH_NEON_VFP_V4},
+ *
+ *
+ * Simplified diagram that only includes FPUs supported by Android:
+ * Only ARCH_VFP_V3D16 is actually mandated by the armeabi-v7a ABI,
+ * all others are optional and must be probed at runtime.
+ *
+ * ARCH_VFP_V3D16 (EXT_V1xD+EXT_V1+EXT_V2+EXT_V3xD+EXT_V3)
+ *   |
+ *   +-------------------+
+ *   |                   |
+ *   |         ARCH_VFP_V3D16_FP16  (+EXT_FP16)
+ *   |
+ *   +-------------------+
+ *   |                   |
+ *   |         ARCH_VFP_V4_D16 (+EXT_FP16+EXT_FMA)
+ *   |                   |
+ *   |         ARCH_VFP_V4 (+EXT_D32)
+ *   |                   |
+ *   |         ARCH_NEON_VFP_V4 (+EXT_NEON+EXT_NEON_FMA)
+ *   |
+ * ARCH_VFP_V3 (+EXT_D32)
+ *   |
+ *   +-------------------+
+ *   |                   |
+ *   |         ARCH_VFP_V3_FP16 (+EXT_FP16)
+ *   |
+ * ARCH_VFP_V3_PLUS_NEON_V1 (+EXT_NEON)
+ *   |
+ * ARCH_NEON_FP16 (+EXT_FP16)
+ *
+ */