2001-10-12 Jakub Jelinek <jakub@redhat.com>
* unwind-dw2.c (frame_state_296): New type.
(__frame_state_for): Add compatibility code with early gcc-2.96-RH.
--- gcc/unwind-dw2.c.jj Wed Oct 3 12:35:24 2001
+++ gcc/unwind-dw2.c Fri Oct 12 18:48:57 2001
@@ -950,14 +950,50 @@ typedef struct frame_state
char saved[DWARF_FRAME_REGISTERS+1];
} frame_state;
-struct frame_state * __frame_state_for (void *, struct frame_state *);
+/* Stock Red Hat Linux 7.0 and 7.1 gcc-2.96-RH used two additional fields. */
+typedef struct frame_state_296
+{
+ frame_state state;
+ long base_offset;
+ char indirect;
+} frame_state_296;
/* Called from pre-G++ 3.0 __throw to find the registers to restore for
a given PC_TARGET. The caller should allocate a local variable of
`struct frame_state' and pass its address to STATE_IN. */
+#if defined(__linux__) && defined(__sparc__) && !defined(__arch64__)
+/* Grab some info from parent register window so that we don't
+ have to flush register windows and look it up on the stack. */
+asm (" .text \n\
+ .globl __frame_state_for \n\
+ .type __frame_state_for, #function \n\
+__frame_state_for: \n\
+ mov %fp, %o2 \n\
+ b ___frame_state_for \n\
+ mov %i0, %o3 \n\
+ ");
+
+static struct frame_state *
+___frame_state_for (void *pc_target, struct frame_state *state_in, void *pfp,
+ int i0);
+
+static struct frame_state *
+___frame_state_for (void *pc_target, struct frame_state *state_in, void *pfp,
+ int i0)
+#elif defined(__linux__) && defined(__alpha__)
+struct frame_state *
+__frame_state_for (void *pc_target, struct frame_state *state_in, long a2);
+
+struct frame_state *
+__frame_state_for (void *pc_target, struct frame_state *state_in, long a2)
+#else
+struct frame_state *
+__frame_state_for (void *pc_target, struct frame_state *state_in);
+
struct frame_state *
__frame_state_for (void *pc_target, struct frame_state *state_in)
+#endif
{
struct _Unwind_Context context;
_Unwind_FrameState fs;
@@ -997,6 +1033,109 @@ __frame_state_for (void *pc_target, stru
state_in->args_size = context.args_size;
state_in->eh_ptr = fs.eh_ptr;
+#ifdef __linux__
+ /* Binary compatibility problem: In June 2000, 2 fields
+ were added at the end of struct frame_state. If for some reason
+ __throw (or __rethrow) comes from binary/shared lib compiled
+ with egcs 1.x.y or gcc-2.95.x and __frame_state_for comes from
+ glibc compiled with gcc-2.96-RH up (gcc-3_0-branch in Apr 2001
+ works that way still), then we can overflow __throw's stack.
+ To fix this, we try to find out who calls us.
+ __frame_state_for is called by next_stack_level and __throw/__rethrow.
+ Of these, __throw/__rethrow does not care about indirect/base_offset
+ fields and next_stack_level can be found out because that's the only
+ routine which where state_in does not point into its stackframe. */
+# ifdef __i386__
+ {
+ unsigned long pbp, bp;
+ unsigned char *ppc;
+
+ asm ("movl (%%ebp), %0; movl 4(%%ebp), %1; movl %%ebp, %2"
+ : "=r" (pbp), "=r" (ppc), "=r" (bp));
+ if (pbp < (unsigned long)state_in && pbp - bp == 0x40)
+ /* We've been called from next_stack_level function.
+ All gcc-2.96-RH rpms shipped by Red Hat satisfy pbp - bp == 64,
+ none egcs 1.x.y Red Hat shipped do. */
+ {
+ unsigned char *end;
+ int indirect = 0;
+
+ /* Skim next_stack_level to see if it compares 0x74(base),0
+ and reads from 0x70(base). Stop at ret instruction. */
+ for (end = ppc + 512; ppc < end && *ppc != 0xc3 && indirect < 2;
+ ppc++)
+ {
+ if (*ppc == 0x74 && ppc[1] == 0)
+ indirect++;
+ else if (*ppc == 0x70)
+ indirect++;
+ }
+ if (indirect == 2)
+ {
+ ((frame_state_296 *) state_in)->base_offset = 0;
+ ((frame_state_296 *) state_in)->indirect = 0;
+ }
+ }
+ }
+# elif defined(__sparc__) && !defined(__arch64__)
+ if (pfp < (unsigned long)state_in && i0 == 0)
+ /* We've been called from next_stack_level function.
+ All gcc-2.96-RH rpms shipped by Red Hat clear %i0 in next_stack_level
+ before calling __frame_state_for, all egcs 1.x.y just copy
+ %i0 into %o0, so it is guaranteed to be non-NULL. */
+ {
+ unsigned int *ppc, *end;
+ int indirect = 0;
+
+ ppc = (unsigned int *) __builtin_return_address (0);
+
+ /* Skim next_stack_level to see if it does a ld?b [? + 0x218]
+ and ld?w [? + 0x214]. Stop at ret instruction. */
+ for (end = ppc + 128; ppc < end && indirect < 2
+ && (*ppc | 0x00080000) != 0x81cfe008; ppc++)
+ switch (*ppc & 0xc1b83fff)
+ {
+ case 0xc0082218: /* ld?b [? + 0x218], ? */
+ case 0xc0002214: /* ld?w [? + 0x214], ? */
+ indirect++;
+ break;
+ }
+ if (indirect == 2)
+ {
+ ((frame_state_296 *) state_in)->base_offset = 0;
+ ((frame_state_296 *) state_in)->indirect = 0;
+ }
+ }
+# elif defined(__alpha__)
+ if ((long)state_in == a2)
+ /* We've been called most probably from next_stack_level (it has 3 arguments
+ and passes its third argument as second argument to __frame_state_for). */
+ {
+ unsigned int *ppc, *end;
+ int indirect = 0;
+
+ ppc = (unsigned int *) __builtin_return_address (0);
+ /* Skim next_stack_level to see if it does a ldq ?,624(?)
+ and ldl ?,632(?) resp. ldbu ?,632(?). Stop at ret instruction. */
+ for (end = ppc + 128; ppc < end && indirect < 2
+ && *ppc != 0x6bfa8001; ppc++)
+ switch (*ppc & 0xfc00ffff)
+ {
+ case 0xa4000270: /* ldq ?,624(?) */
+ case 0xa0000278: /* ldl ?,632(?) */
+ case 0xa8000278: /* ldbu ?,632(?) */
+ indirect++;
+ break;
+ }
+ if (indirect == 2)
+ {
+ ((frame_state_296 *) state_in)->base_offset = 0;
+ ((frame_state_296 *) state_in)->indirect = 0;
+ }
+ }
+# endif
+#endif
+
return state_in;
}
