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PPC: call libm helpers via private GOT to fix linking with GCC 12+ #271

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PPC: call libm helpers via private GOT to fix linking with GCC 12+ #271

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11 changes: 10 additions & 1 deletion src/lj_dispatch.c
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Original file line number Diff line number Diff line change
Expand Up @@ -56,6 +56,15 @@ static const ASMFunction dispatch_got[] = {
#undef GOTFUNC
#endif

#if LJ_TARGET_PPC && LJ_32
#include <math.h>
#define GOTFUNC(name) (ASMFunction)name,
static const ASMFunction dispatch_got[] = {
GOTDEF(GOTFUNC)
};
#undef GOTFUNC
#endif

/* Initialize instruction dispatch table and hot counters. */
void lj_dispatch_init(GG_State *GG)
{
Expand All @@ -76,7 +85,7 @@ void lj_dispatch_init(GG_State *GG)
GG->g.bc_cfunc_ext = GG->g.bc_cfunc_int = BCINS_AD(BC_FUNCC, LUA_MINSTACK, 0);
for (i = 0; i < GG_NUM_ASMFF; i++)
GG->bcff[i] = BCINS_AD(BC__MAX+i, 0, 0);
#if LJ_TARGET_MIPS
#if LJ_TARGET_MIPS || (LJ_TARGET_PPC && LJ_32)
memcpy(GG->got, dispatch_got, LJ_GOT__MAX*sizeof(ASMFunction *));
#endif
}
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32 changes: 31 additions & 1 deletion src/lj_dispatch.h
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Expand Up @@ -66,6 +66,36 @@ GOTDEF(GOTENUM)
};
#endif

#if LJ_TARGET_PPC && LJ_32
/* Call libm/libgcc helpers via our own GOT instead of the PLT. A PLT call
** from the VM assembler forces the obsolete BSS-PLT for the whole link,
** which fails against secure-PLT objects emitted by GCC 12 and newer.
*/
#if LJ_SOFTFP
#ifndef _LJ_IRCALL_H
extern double __ledf2(double a, double b);
extern double __adddf3(double a, double b);
extern double __subdf3(double a, double b);
extern double __muldf3(double a, double b);
extern double __divdf3(double a, double b);
#endif
#define SFGOTDEF(_) _(__ledf2) _(__adddf3) _(__subdf3) _(__muldf3) _(__divdf3)
#else
#define SFGOTDEF(_)
#endif
#define GOTDEF(_) \
_(floor) _(ceil) _(trunc) _(log) _(log10) _(exp) _(sin) _(cos) _(tan) \
_(asin) _(acos) _(atan) _(sinh) _(cosh) _(tanh) _(frexp) _(modf) _(atan2) \
_(pow) _(fmod) _(ldexp) _(sqrt) SFGOTDEF(_)

enum {
#define GOTENUM(name) LJ_GOT_##name,
GOTDEF(GOTENUM)
#undef GOTENUM
LJ_GOT__MAX
};
#endif

/* Type of hot counter. Must match the code in the assembler VM. */
/* 16 bits are sufficient. Only 0.0015% overhead with maximum slot penalty. */
typedef uint16_t HotCount;
Expand Down Expand Up @@ -93,7 +123,7 @@ typedef struct GG_State {
/* Make g reachable via K12 encoded DISPATCH-relative addressing. */
uint8_t align1[(16-sizeof(global_State))&15];
#endif
#if LJ_TARGET_MIPS
#if LJ_TARGET_MIPS || (LJ_TARGET_PPC && LJ_32)
ASMFunction got[LJ_GOT__MAX]; /* Global offset table. */
#endif
#if LJ_HASJIT
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12 changes: 11 additions & 1 deletion src/vm_ppc.dasc
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Original file line number Diff line number Diff line change
Expand Up @@ -50,7 +50,13 @@
|.macro blex, target; bl extern target; nop; .endmacro
|.macro .toc, a, b; a, b; .endmacro
|.else
|.macro blex, target; bl extern target@plt; .endmacro
|// Call via our own GOT to avoid PLT relocations, which force the obsolete
|// BSS-PLT on PPC32 and break linking against secure-PLT objects.
|.macro blex, target
| lwz TMP0, DISPATCH_GOT(target)(DISPATCH)
| mtctr TMP0
| bctrl
|.endmacro
|.macro .toc, a, b; .endmacro
|.endif
|.if OPD
Expand Down Expand Up @@ -577,6 +583,10 @@
|// Assumes DISPATCH is relative to GL.
#define DISPATCH_GL(field) (GG_DISP2G + (int)offsetof(global_State, field))
#define DISPATCH_J(field) (GG_DISP2J + (int)offsetof(jit_State, field))
#if LJ_TARGET_PPC && LJ_32
#define GG_DISP2GOT (GG_OFS(got) - GG_OFS(dispatch))
#define DISPATCH_GOT(name) (GG_DISP2GOT + 4*LJ_GOT_##name)
#endif
|
#define PC2PROTO(field) ((int)offsetof(GCproto, field)-(int)sizeof(GCproto))
|
Expand Down