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#ifndef PICKNO
# define PICKNO 1
#endif
#if PICKNO == 2
# define PICK(fn1, fn2) #fn2
#else
# define PICK(fn1, fn2) #fn1
#endif
#ifdef __x86_64__
# define IFUNC_ASM(fn) "\tleaq " fn "(%rip), %rax\n\tretq\n"
#elif defined __i386__
# ifdef __PIC__
# define IFUNC_ASM(fn) "\tcall 1f\n1:\tpopl %ecx\n" \
"\taddl $_GLOBAL_OFFSET_TABLE_+[.-1b], %ecx\n" \
"\tleal " fn "@GOTOFF(%ecx), %eax\n\tret\n"
# else
# define IFUNC_ASM(fn) "\tmovl $" fn ", %eax\n\tret\n"
# endif
#elif defined __powerpc__
# define IFUNC_ASM(fn) "\tmflr 12\n\tbcl 20,31,1f\n" \
"\t1:mflr 3\n\tmtlr 12\n\taddis 3,3, " fn \
"-1b@ha\n\taddi 3,3," fn "-1b@l\n\tblr\n"
# if defined __powerpc64__
# define IFUNC_DECL(name, hidden, fn1, fn2) \
asm (".text\n" \
"\t.globl " #name "\n" \
"\t" hidden " " #name "\n" \
"\t.type " #name ", @gnu_indirect_function\n" \
"\t.section .opd,\"aw\"\n" \
"\t.align 3\n" \
#name ":\n" \
"\t.quad .L." #name ",.TOC.@tocbase,0\n" \
"\t.previous\n" \
".L." #name ":\n" \
IFUNC_ASM (PICK (fn1, fn2)) \
"\t.size " #name ", .-" #name "\n")
# endif
#else
# error Architecture not supported
#endif
#ifndef IFUNC_DECL
#define IFUNC_DECL(name, hidden, fn1, fn2) \
asm (".text\n" \
"\t.globl " #name "\n" \
"\t" hidden " " #name "\n" \
"\t.type " #name ", @gnu_indirect_function\n" \
#name ":\n" \
IFUNC_ASM (PICK (fn1, fn2)) \
"\t.size " #name ", .-" #name "\n")
#endif
#define IFUNC(name, hidden, fn1, fn2) \
extern __typeof (fn1) fn1 __attribute__((used)); \
extern __typeof (fn2) fn2 __attribute__((used)); \
extern __typeof (fn1) name; \
IFUNC_DECL (name, hidden, fn1, fn2)
#define IFUNC_LOCAL(name, fn1, fn2) IFUNC(name, ".hidden", fn1, fn2)
#define IFUNC_GLOBAL(name, fn1, fn2) IFUNC(name, ".globl", fn1, fn2)
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