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* sparc-tdep.c (X_RS2): New macro.

Browse Source 
(sparc_skip_stack_check): New function.
        (sparc_analyze_prologue): Adjust PC past stack probing
        sequence if necessary.
This commit is contained in:
Joel Brobecker 2007-04-11 07:10:08 +00:00
parent 14ee09e13c
commit b0b9258645
2 changed files with 160 additions and 0 deletions
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7
gdb/ChangeLog
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@ -1,3 +1,10 @@
2007-04-11 Joel Brobecker <brobecker@adacore.com>
* sparc-tdep.c (X_RS2): New macro.
(sparc_skip_stack_check): New function.
(sparc_analyze_prologue): Adjust PC past stack probing
sequence if necessary.
2007-04-10 Andreas Schwab <schwab@suse.de>
* rs6000-tdep.c (rs6000_dwarf2_reg_to_regnum): Decode 64 as CR

153
gdb/sparc-tdep.c
View File

@ -82,6 +82,7 @@ struct regset;
#define X_IMM22(i) ((i) & 0x3fffff)
#define X_OP3(i) (((i) >> 19) & 0x3f)
#define X_RS1(i) (((i) >> 14) & 0x1f)
#define X_RS2(i) ((i) & 0x1f)
#define X_I(i) (((i) >> 13) & 1)
/* Sign extension macros. */
#define X_DISP22(i) ((X_IMM22 (i) ^ 0x200000) - 0x200000)
@ -571,6 +572,156 @@ sparc_alloc_frame_cache (void)
return cache;
}
/* GCC generates several well-known sequences of instructions at the begining
of each function prologue when compiling with -fstack-check. If one of
such sequences starts at START_PC, then return the address of the
instruction immediately past this sequence. Otherwise, return START_PC. */
static CORE_ADDR
sparc_skip_stack_check (const CORE_ADDR start_pc)
{
CORE_ADDR pc = start_pc;
unsigned long insn;
int offset_stack_checking_sequence = 0;
/* With GCC, all stack checking sequences begin with the same two
instructions. */
/* sethi <some immediate>,%g1 */
insn = sparc_fetch_instruction (pc);
pc = pc + 4;
if (!(X_OP (insn) == 0 && X_OP2 (insn) == 0x4 && X_RD (insn) == 1))
return start_pc;
/* sub %sp, %g1, %g1 */
insn = sparc_fetch_instruction (pc);
pc = pc + 4;
if (!(X_OP (insn) == 2 && X_OP3 (insn) == 0x4 && !X_I(insn)
&& X_RD (insn) == 1 && X_RS1 (insn) == 14 && X_RS2 (insn) == 1))
return start_pc;
insn = sparc_fetch_instruction (pc);
pc = pc + 4;
/* First possible sequence:
[first two instructions above]
clr [%g1 - some immediate] */
/* clr [%g1 - some immediate] */
if (X_OP (insn) == 3 && X_OP3(insn) == 0x4 && X_I(insn)
&& X_RS1 (insn) == 1 && X_RD (insn) == 0)
{
/* Valid stack-check sequence, return the new PC. */
return pc;
}
/* Second possible sequence: A small number of probes.
[first two instructions above]
clr [%g1]
add %g1, -<some immediate>, %g1
clr [%g1]
[repeat the two instructions above any (small) number of times]
clr [%g1 - some immediate] */
/* clr [%g1] */
else if (X_OP (insn) == 3 && X_OP3(insn) == 0x4 && !X_I(insn)
&& X_RS1 (insn) == 1 && X_RD (insn) == 0)
{
while (1)
{
/* add %g1, -<some immediate>, %g1 */
insn = sparc_fetch_instruction (pc);
pc = pc + 4;
if (!(X_OP (insn) == 2 && X_OP3(insn) == 0 && X_I(insn)
&& X_RS1 (insn) == 1 && X_RD (insn) == 1))
break;
/* clr [%g1] */
insn = sparc_fetch_instruction (pc);
pc = pc + 4;
if (!(X_OP (insn) == 3 && X_OP3(insn) == 0x4 && !X_I(insn)
&& X_RD (insn) == 0 && X_RS1 (insn) == 1))
return start_pc;
}
/* clr [%g1 - some immediate] */
if (!(X_OP (insn) == 3 && X_OP3(insn) == 0x4 && X_I(insn)
&& X_RS1 (insn) == 1 && X_RD (insn) == 0))
return start_pc;
/* We found a valid stack-check sequence, return the new PC. */
return pc;
}
/* Third sequence: A probing loop.
[first two instructions above]
sethi <some immediate>, %g4
sub %g1, %g4, %g4
cmp %g1, %g4
be <disp>
add %g1, -<some immediate>, %g1
ba <disp>
clr [%g1]
clr [%g4 - some immediate] */
/* sethi <some immediate>, %g4 */
else if (X_OP (insn) == 0 && X_OP2 (insn) == 0x4 && X_RD (insn) == 4)
{
/* sub %g1, %g4, %g4 */
insn = sparc_fetch_instruction (pc);
pc = pc + 4;
if (!(X_OP (insn) == 2 && X_OP3 (insn) == 0x4 && !X_I(insn)
&& X_RD (insn) == 4 && X_RS1 (insn) == 1 && X_RS2 (insn) == 4))
return start_pc;
/* cmp %g1, %g4 */
insn = sparc_fetch_instruction (pc);
pc = pc + 4;
if (!(X_OP (insn) == 2 && X_OP3 (insn) == 0x14 && !X_I(insn)
&& X_RD (insn) == 0 && X_RS1 (insn) == 1 && X_RS2 (insn) == 4))
return start_pc;
/* be <disp> */
insn = sparc_fetch_instruction (pc);
pc = pc + 4;
if (!(X_OP (insn) == 0 && X_COND (insn) == 0x1))
return start_pc;
/* add %g1, -<some immediate>, %g1 */
insn = sparc_fetch_instruction (pc);
pc = pc + 4;
if (!(X_OP (insn) == 2 && X_OP3(insn) == 0 && X_I(insn)
&& X_RS1 (insn) == 1 && X_RD (insn) == 1))
return start_pc;
/* ba <disp> */
insn = sparc_fetch_instruction (pc);
pc = pc + 4;
if (!(X_OP (insn) == 0 && X_COND (insn) == 0x8))
return start_pc;
/* clr [%g1] */
insn = sparc_fetch_instruction (pc);
pc = pc + 4;
if (!(X_OP (insn) == 3 && X_OP3(insn) == 0x4 && !X_I(insn)
&& X_RD (insn) == 0 && X_RS1 (insn) == 1))
return start_pc;
/* clr [%g4 - some immediate] */
insn = sparc_fetch_instruction (pc);
pc = pc + 4;
if (!(X_OP (insn) == 3 && X_OP3(insn) == 0x4 && X_I(insn)
&& X_RS1 (insn) == 4 && X_RD (insn) == 0))
return start_pc;
/* We found a valid stack-check sequence, return the new PC. */
return pc;
}
/* No stack check code in our prologue, return the start_pc. */
return start_pc;
}
CORE_ADDR
sparc_analyze_prologue (CORE_ADDR pc, CORE_ADDR current_pc,
struct sparc_frame_cache *cache)
@ -580,6 +731,8 @@ sparc_analyze_prologue (CORE_ADDR pc, CORE_ADDR current_pc,
int offset = 0;
int dest = -1;
pc = sparc_skip_stack_check (pc);
if (current_pc <= pc)
return current_pc;