fptr.c (__canonicalize_funcptr_for_compare): New file and function.
* pa/fptr.c (__canonicalize_funcptr_for_compare): New file and function. * pa.md (canonicalize_funcptr_for_compare): Output library call to canonicalize_funcptr_for_compare_libfunc on TARGET_ELF32. * pa32-linux.h (CANONICALIZE_FUNCPTR_FOR_COMPARE_LIBCALL, CTOR_LIST_BEGIN): New defines. * pa/t-linux (LIB2FUNCS_EXTRA): New define. (fptr.c): Add make rules. From-SVN: r59842
This commit is contained in:
John David Anglin
John David Anglin
parent
16823694d5
commit
9e1ab8c1a5
@ -1,3 +1,13 @@
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2002-12-04 John David Anglin <dave@hiauly1.hia.nrc.ca>
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* pa/fptr.c (__canonicalize_funcptr_for_compare): New file and function.
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* pa.md (canonicalize_funcptr_for_compare): Output library call to
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canonicalize_funcptr_for_compare_libfunc on TARGET_ELF32.
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* pa32-linux.h (CANONICALIZE_FUNCPTR_FOR_COMPARE_LIBCALL,
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CTOR_LIST_BEGIN): New defines.
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* pa/t-linux (LIB2FUNCS_EXTRA): New define.
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(fptr.c): Add make rules.
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2002-12-04 Geoffrey Keating <geoffk@apple.com>
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* combine.c (combine_simplify_rtx): Add new canonicalizations.
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127
gcc/config/pa/fptr.c
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127
gcc/config/pa/fptr.c
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@ -0,0 +1,127 @@
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/* Subroutine for function pointer canonicalization on PA-RISC with ELF32.
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Copyright 2002 Free Software Foundation, Inc.
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Contributed by John David Anglin (dave.anglin@nrc.ca).
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This file is part of GNU CC.
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GNU CC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU CC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU CC; see the file COPYING. If not, write to
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the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* WARNING: The code is this function depends on internal and undocumented
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details of the GNU linker and dynamic loader as implemented for parisc
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linux. */
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/* This MUST match the defines sysdeps/hppa/dl-machine.h and
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bfd/elf32-hppa.c. */
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#define GOT_FROM_PLT_STUB (4*4)
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/* List of byte offsets in _dl_runtime_resolve to search for "bl" branches.
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The first "bl" branch instruction found MUST be a call to fixup. See
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the define for TRAMPOLINE_TEMPLATE in sysdeps/hppa/dl-machine.h. If
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the trampoline template is changed, the list must be appropriately
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updated. The offset of -4 allows for a magic branch at the start of
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the template should it be necessary to change the current branch
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position. */
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#define NOFFSETS 2
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static int fixup_branch_offset[NOFFSETS] = { 32, -4 };
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#define GET_FIELD(X, FROM, TO) \
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((X) >> (31 - (TO)) & ((1 << ((TO) - (FROM) + 1)) - 1))
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#define SIGN_EXTEND(VAL,BITS) \
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((int) ((VAL) >> ((BITS) - 1) ? (-1 << (BITS)) | (VAL) : (VAL)))
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struct link_map;
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typedef int (*fptr_t) (void);
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typedef int (*fixup_t) (struct link_map *, unsigned int);
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extern unsigned int _GLOBAL_OFFSET_TABLE_;
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/* __canonicalize_funcptr_for_compare must be hidden so that it is not
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placed in the dynamic symbol table. Like millicode functions, it
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must be linked into all binaries in order access the got table of
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that binary. However, we don't use the millicode calling convention
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and the routine must be a normal function so that it can be compiled
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as pic code. */
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unsigned int __canonicalize_funcptr_for_compare (fptr_t)
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__attribute__ ((visibility ("hidden")));
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unsigned int
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__canonicalize_funcptr_for_compare (fptr)
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fptr_t fptr;
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{
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static unsigned int fixup_plabel[2];
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static fixup_t fixup;
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unsigned int *plabel, *got;
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/* -1 is special. It is used in crtend to mark the end of a list of
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function pointers. Also return immediately if the plabel bit is
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not set in the function pointer. In this case, the function pointer
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points directly to the function. */
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if ((int) fptr == -1 || !((int) fptr & 2))
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return (unsigned int) fptr;
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/* The function pointer points to a function descriptor (plabel). If
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the plabel hasn't been resolved, the first word of the plabel points
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to the entry of the PLT stub just before the global offset table.
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The second word in the plabel contains the relocation offset for the
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function. */
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plabel = (unsigned int *) ((unsigned int) fptr & ~3);
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got = (unsigned int *) (plabel[0] + GOT_FROM_PLT_STUB);
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/* Return the address of the function if the plabel has been resolved. */
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if (got != &_GLOBAL_OFFSET_TABLE_)
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return plabel[0];
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/* Initialize our plabel for calling fixup if we haven't done so already.
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This code needs to be thread safe but we don't have to be too careful
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as the result is invariant. */
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if (!fixup)
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{
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int i;
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unsigned int *iptr;
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/* Find the first "bl" branch in the offset search list. This is a
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call to fixup or a magic branch to fixup at the beginning of the
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trampoline template. The fixup function does the actual runtime
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resolution of function decriptors. We only look for "bl" branches
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with a 17-bit pc-relative displacement. */
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for (i = 0; i < NOFFSETS; i++)
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{
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iptr = (unsigned int *) (got[-2] + fixup_branch_offset[i]);
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if ((*iptr & 0xfc00e000) == 0xe8000000)
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break;
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}
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/* This should not happen... */
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if (i == NOFFSETS)
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return ~0;
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/* Extract the 17-bit displacement from the instruction. */
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iptr += SIGN_EXTEND (GET_FIELD (*iptr, 19, 28) |
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GET_FIELD (*iptr, 29, 29) << 10 |
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GET_FIELD (*iptr, 11, 15) << 11 |
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GET_FIELD (*iptr, 31, 31) << 16, 17);
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/* Build a plabel for an indirect call to fixup. */
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fixup_plabel[0] = (unsigned int) iptr + 8; /* address of fixup */
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fixup_plabel[1] = got[-1]; /* ltp for fixup */
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fixup = (fixup_t) ((int) fixup_plabel | 3);
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}
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/* Call fixup to resolve the function address. got[1] contains the
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link_map pointer and plabel[1] the relocation offset. */
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fixup ((struct link_map *) got[1], plabel[1]);
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return plabel[0];
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}
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@ -7277,9 +7277,20 @@
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(clobber (reg:SI 31))])
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(set (match_operand:SI 0 "register_operand" "")
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(reg:SI 29))]
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"! TARGET_PORTABLE_RUNTIME && !TARGET_64BIT && !TARGET_ELF32"
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"!TARGET_PORTABLE_RUNTIME && !TARGET_64BIT"
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"
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{
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if (TARGET_ELF32)
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{
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rtx canonicalize_funcptr_for_compare_libfunc
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= init_one_libfunc (CANONICALIZE_FUNCPTR_FOR_COMPARE_LIBCALL);
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emit_library_call_value (canonicalize_funcptr_for_compare_libfunc,
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operands[0], LCT_NORMAL, Pmode,
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1, operands[1], Pmode);
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DONE;
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}
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operands[2] = gen_reg_rtx (SImode);
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if (GET_CODE (operands[1]) != REG)
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{
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@ -29,3 +29,22 @@ Boston, MA 02111-1307, USA. */
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subspace stubs, so we allow sibcalls to all functions. */
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#undef FUNCTION_OK_FOR_SIBCALL
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#define FUNCTION_OK_FOR_SIBCALL(DECL) 1
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/* We need a libcall to canonicalize function pointers because of
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the way function pointers are handled when doing lazy linking. */
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#define CANONICALIZE_FUNCPTR_FOR_COMPARE_LIBCALL \
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"__canonicalize_funcptr_for_compare"
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/* The libcall __canonicalize_funcptr_for_compare is referenced in
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crtend.o and the reference isn't resolved in objects that don't
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compare function pointers. Thus, we need to play games to provide
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a reference in crtbegin.o. The rest of the define is the same
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as that in crtstuff.c */
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#define CTOR_LIST_BEGIN \
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asm (".type __canonicalize_funcptr_for_compare,@function\n" \
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" .text\n" \
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" .word __canonicalize_funcptr_for_compare-$PIC_pcrel$0"); \
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STATIC func_ptr __CTOR_LIST__[1] \
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__attribute__ ((__unused__, section(".ctors"), \
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aligned(sizeof(func_ptr)))) \
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= { (func_ptr) (-1) }
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@ -5,8 +5,14 @@
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LIB1ASMFUNCS = _divI _divU _remI _remU _div_const _mulI _dyncall
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LIB1ASMSRC = pa/milli64.S
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# Compile crtbeginS.o and crtendS.o as PIC.
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CRTSTUFF_T_CFLAGS_S = -fPIC
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# Compile libgcc2.a as PIC.
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TARGET_LIBGCC2_CFLAGS = -fPIC -DELF=1 -DLINUX=1
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LIB2FUNCS_EXTRA=fptr.c
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fptr.c: $(srcdir)/config/pa/fptr.c
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rm -f fptr.c
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cp $(srcdir)/config/pa/fptr.c .
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# Compile crtbeginS.o and crtendS.o as PIC.
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CRTSTUFF_T_CFLAGS_S = -fPIC
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