From 6b9801d456c0851563f41b87cfdf00b141257578 Mon Sep 17 00:00:00 2001 From: Stan Shebs Date: Thu, 15 Sep 2011 22:54:13 +0000 Subject: [PATCH] * server.h (struct emit_ops): Add compare-goto fields. * tracepoint.c (gdb_agent_op_sizes): New table. (emit_eq_goto): New function. (emit_ne_goto): New function. (emit_lt_goto): New function. (emit_le_goto): New function. (emit_gt_goto): New function. (emit_ge_goto): New function. (is_goto_target): New function. (compile_bytecodes): Recognize special cases of compare-goto combinations and call specialized emitters for them. * linux-x86-low.c (amd64_emit_eq_goto): New function. (amd64_emit_ne_goto): New function. (amd64_emit_lt_goto): New function. (amd64_emit_le_goto): New function. (amd64_emit_gt_goto): New function. (amd64_emit_ge_goto): New function. (amd64_emit_ops): Add the new functions. (i386_emit_eq_goto): New function. (i386_emit_ne_goto): New function. (i386_emit_lt_goto): New function. (i386_emit_le_goto): New function. (i386_emit_gt_goto): New function. (i386_emit_ge_goto): New function. (i386_emit_ops): Add the new functions. --- gdb/gdbserver/ChangeLog | 28 ++++ gdb/gdbserver/linux-x86-low.c | 293 +++++++++++++++++++++++++++++++++- gdb/gdbserver/server.h | 9 ++ gdb/gdbserver/tracepoint.c | 160 ++++++++++++++++++- 4 files changed, 484 insertions(+), 6 deletions(-) diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog index 91fee1a6b5..b634f5f667 100644 --- a/gdb/gdbserver/ChangeLog +++ b/gdb/gdbserver/ChangeLog @@ -1,3 +1,31 @@ +2011-09-15 Stan Shebs + + * server.h (struct emit_ops): Add compare-goto fields. + * tracepoint.c (gdb_agent_op_sizes): New table. + (emit_eq_goto): New function. + (emit_ne_goto): New function. + (emit_lt_goto): New function. + (emit_le_goto): New function. + (emit_gt_goto): New function. + (emit_ge_goto): New function. + (is_goto_target): New function. + (compile_bytecodes): Recognize special cases of compare-goto + combinations and call specialized emitters for them. + * linux-x86-low.c (amd64_emit_eq_goto): New function. + (amd64_emit_ne_goto): New function. + (amd64_emit_lt_goto): New function. + (amd64_emit_le_goto): New function. + (amd64_emit_gt_goto): New function. + (amd64_emit_ge_goto): New function. + (amd64_emit_ops): Add the new functions. + (i386_emit_eq_goto): New function. + (i386_emit_ne_goto): New function. + (i386_emit_lt_goto): New function. + (i386_emit_le_goto): New function. + (i386_emit_gt_goto): New function. + (i386_emit_ge_goto): New function. + (i386_emit_ops): Add the new functions. + 2011-09-08 Stan Shebs * linux-x86-low.c (i386_emit_prologue): Save %ebx. diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c index 8a3a597ebf..4cc3feb956 100644 --- a/gdb/gdbserver/linux-x86-low.c +++ b/gdb/gdbserver/linux-x86-low.c @@ -1993,6 +1993,127 @@ amd64_emit_void_call_2 (CORE_ADDR fn, int arg1) "pop %rax"); } +void +amd64_emit_eq_goto (int *offset_p, int *size_p) +{ + EMIT_ASM (amd64_eq, + "cmp %rax,(%rsp)\n\t" + "jne .Lamd64_eq_fallthru\n\t" + "lea 0x8(%rsp),%rsp\n\t" + "pop %rax\n\t" + /* jmp, but don't trust the assembler to choose the right jump */ + ".byte 0xe9, 0x0, 0x0, 0x0, 0x0\n\t" + ".Lamd64_eq_fallthru:\n\t" + "lea 0x8(%rsp),%rsp\n\t" + "pop %rax"); + + if (offset_p) + *offset_p = 13; + if (size_p) + *size_p = 4; +} + +void +amd64_emit_ne_goto (int *offset_p, int *size_p) +{ + EMIT_ASM (amd64_ne, + "cmp %rax,(%rsp)\n\t" + "je .Lamd64_ne_fallthru\n\t" + "lea 0x8(%rsp),%rsp\n\t" + "pop %rax\n\t" + /* jmp, but don't trust the assembler to choose the right jump */ + ".byte 0xe9, 0x0, 0x0, 0x0, 0x0\n\t" + ".Lamd64_ne_fallthru:\n\t" + "lea 0x8(%rsp),%rsp\n\t" + "pop %rax"); + + if (offset_p) + *offset_p = 13; + if (size_p) + *size_p = 4; +} + +void +amd64_emit_lt_goto (int *offset_p, int *size_p) +{ + EMIT_ASM (amd64_lt, + "cmp %rax,(%rsp)\n\t" + "jnl .Lamd64_lt_fallthru\n\t" + "lea 0x8(%rsp),%rsp\n\t" + "pop %rax\n\t" + /* jmp, but don't trust the assembler to choose the right jump */ + ".byte 0xe9, 0x0, 0x0, 0x0, 0x0\n\t" + ".Lamd64_lt_fallthru:\n\t" + "lea 0x8(%rsp),%rsp\n\t" + "pop %rax"); + + if (offset_p) + *offset_p = 13; + if (size_p) + *size_p = 4; +} + +void +amd64_emit_le_goto (int *offset_p, int *size_p) +{ + EMIT_ASM (amd64_le, + "cmp %rax,(%rsp)\n\t" + "jnle .Lamd64_le_fallthru\n\t" + "lea 0x8(%rsp),%rsp\n\t" + "pop %rax\n\t" + /* jmp, but don't trust the assembler to choose the right jump */ + ".byte 0xe9, 0x0, 0x0, 0x0, 0x0\n\t" + ".Lamd64_le_fallthru:\n\t" + "lea 0x8(%rsp),%rsp\n\t" + "pop %rax"); + + if (offset_p) + *offset_p = 13; + if (size_p) + *size_p = 4; +} + +void +amd64_emit_gt_goto (int *offset_p, int *size_p) +{ + EMIT_ASM (amd64_gt, + "cmp %rax,(%rsp)\n\t" + "jng .Lamd64_gt_fallthru\n\t" + "lea 0x8(%rsp),%rsp\n\t" + "pop %rax\n\t" + /* jmp, but don't trust the assembler to choose the right jump */ + ".byte 0xe9, 0x0, 0x0, 0x0, 0x0\n\t" + ".Lamd64_gt_fallthru:\n\t" + "lea 0x8(%rsp),%rsp\n\t" + "pop %rax"); + + if (offset_p) + *offset_p = 13; + if (size_p) + *size_p = 4; +} + +void +amd64_emit_ge_goto (int *offset_p, int *size_p) +{ + EMIT_ASM (amd64_ge, + "cmp %rax,(%rsp)\n\t" + "jnge .Lamd64_ge_fallthru\n\t" + ".Lamd64_ge_jump:\n\t" + "lea 0x8(%rsp),%rsp\n\t" + "pop %rax\n\t" + /* jmp, but don't trust the assembler to choose the right jump */ + ".byte 0xe9, 0x0, 0x0, 0x0, 0x0\n\t" + ".Lamd64_ge_fallthru:\n\t" + "lea 0x8(%rsp),%rsp\n\t" + "pop %rax"); + + if (offset_p) + *offset_p = 13; + if (size_p) + *size_p = 4; +} + struct emit_ops amd64_emit_ops = { amd64_emit_prologue, @@ -2025,7 +2146,13 @@ struct emit_ops amd64_emit_ops = amd64_emit_swap, amd64_emit_stack_adjust, amd64_emit_int_call_1, - amd64_emit_void_call_2 + amd64_emit_void_call_2, + amd64_emit_eq_goto, + amd64_emit_ne_goto, + amd64_emit_lt_goto, + amd64_emit_le_goto, + amd64_emit_gt_goto, + amd64_emit_ge_goto }; #endif /* __x86_64__ */ @@ -2500,6 +2627,162 @@ i386_emit_void_call_2 (CORE_ADDR fn, int arg1) "pop %eax"); } + +void +i386_emit_eq_goto (int *offset_p, int *size_p) +{ + EMIT_ASM32 (eq, + /* Check low half first, more likely to be decider */ + "cmpl %eax,(%esp)\n\t" + "jne .Leq_fallthru\n\t" + "cmpl %ebx,4(%esp)\n\t" + "jne .Leq_fallthru\n\t" + "lea 0x8(%esp),%esp\n\t" + "pop %eax\n\t" + "pop %ebx\n\t" + /* jmp, but don't trust the assembler to choose the right jump */ + ".byte 0xe9, 0x0, 0x0, 0x0, 0x0\n\t" + ".Leq_fallthru:\n\t" + "lea 0x8(%esp),%esp\n\t" + "pop %eax\n\t" + "pop %ebx"); + + if (offset_p) + *offset_p = 18; + if (size_p) + *size_p = 4; +} + +void +i386_emit_ne_goto (int *offset_p, int *size_p) +{ + EMIT_ASM32 (ne, + /* Check low half first, more likely to be decider */ + "cmpl %eax,(%esp)\n\t" + "jne .Lne_jump\n\t" + "cmpl %ebx,4(%esp)\n\t" + "je .Lne_fallthru\n\t" + ".Lne_jump:\n\t" + "lea 0x8(%esp),%esp\n\t" + "pop %eax\n\t" + "pop %ebx\n\t" + /* jmp, but don't trust the assembler to choose the right jump */ + ".byte 0xe9, 0x0, 0x0, 0x0, 0x0\n\t" + ".Lne_fallthru:\n\t" + "lea 0x8(%esp),%esp\n\t" + "pop %eax\n\t" + "pop %ebx"); + + if (offset_p) + *offset_p = 18; + if (size_p) + *size_p = 4; +} + +void +i386_emit_lt_goto (int *offset_p, int *size_p) +{ + EMIT_ASM32 (lt, + "cmpl %ebx,4(%esp)\n\t" + "jl .Llt_jump\n\t" + "jne .Llt_fallthru\n\t" + "cmpl %eax,(%esp)\n\t" + "jnl .Llt_fallthru\n\t" + ".Llt_jump:\n\t" + "lea 0x8(%esp),%esp\n\t" + "pop %eax\n\t" + "pop %ebx\n\t" + /* jmp, but don't trust the assembler to choose the right jump */ + ".byte 0xe9, 0x0, 0x0, 0x0, 0x0\n\t" + ".Llt_fallthru:\n\t" + "lea 0x8(%esp),%esp\n\t" + "pop %eax\n\t" + "pop %ebx"); + + if (offset_p) + *offset_p = 20; + if (size_p) + *size_p = 4; +} + +void +i386_emit_le_goto (int *offset_p, int *size_p) +{ + EMIT_ASM32 (le, + "cmpl %ebx,4(%esp)\n\t" + "jle .Lle_jump\n\t" + "jne .Lle_fallthru\n\t" + "cmpl %eax,(%esp)\n\t" + "jnle .Lle_fallthru\n\t" + ".Lle_jump:\n\t" + "lea 0x8(%esp),%esp\n\t" + "pop %eax\n\t" + "pop %ebx\n\t" + /* jmp, but don't trust the assembler to choose the right jump */ + ".byte 0xe9, 0x0, 0x0, 0x0, 0x0\n\t" + ".Lle_fallthru:\n\t" + "lea 0x8(%esp),%esp\n\t" + "pop %eax\n\t" + "pop %ebx"); + + if (offset_p) + *offset_p = 20; + if (size_p) + *size_p = 4; +} + +void +i386_emit_gt_goto (int *offset_p, int *size_p) +{ + EMIT_ASM32 (gt, + "cmpl %ebx,4(%esp)\n\t" + "jg .Lgt_jump\n\t" + "jne .Lgt_fallthru\n\t" + "cmpl %eax,(%esp)\n\t" + "jng .Lgt_fallthru\n\t" + ".Lgt_jump:\n\t" + "lea 0x8(%esp),%esp\n\t" + "pop %eax\n\t" + "pop %ebx\n\t" + /* jmp, but don't trust the assembler to choose the right jump */ + ".byte 0xe9, 0x0, 0x0, 0x0, 0x0\n\t" + ".Lgt_fallthru:\n\t" + "lea 0x8(%esp),%esp\n\t" + "pop %eax\n\t" + "pop %ebx"); + + if (offset_p) + *offset_p = 20; + if (size_p) + *size_p = 4; +} + +void +i386_emit_ge_goto (int *offset_p, int *size_p) +{ + EMIT_ASM32 (ge, + "cmpl %ebx,4(%esp)\n\t" + "jge .Lge_jump\n\t" + "jne .Lge_fallthru\n\t" + "cmpl %eax,(%esp)\n\t" + "jnge .Lge_fallthru\n\t" + ".Lge_jump:\n\t" + "lea 0x8(%esp),%esp\n\t" + "pop %eax\n\t" + "pop %ebx\n\t" + /* jmp, but don't trust the assembler to choose the right jump */ + ".byte 0xe9, 0x0, 0x0, 0x0, 0x0\n\t" + ".Lge_fallthru:\n\t" + "lea 0x8(%esp),%esp\n\t" + "pop %eax\n\t" + "pop %ebx"); + + if (offset_p) + *offset_p = 20; + if (size_p) + *size_p = 4; +} + struct emit_ops i386_emit_ops = { i386_emit_prologue, @@ -2532,7 +2815,13 @@ struct emit_ops i386_emit_ops = i386_emit_swap, i386_emit_stack_adjust, i386_emit_int_call_1, - i386_emit_void_call_2 + i386_emit_void_call_2, + i386_emit_eq_goto, + i386_emit_ne_goto, + i386_emit_lt_goto, + i386_emit_le_goto, + i386_emit_gt_goto, + i386_emit_ge_goto }; diff --git a/gdb/gdbserver/server.h b/gdb/gdbserver/server.h index 164d46bebf..7c682dcca7 100644 --- a/gdb/gdbserver/server.h +++ b/gdb/gdbserver/server.h @@ -538,6 +538,15 @@ struct emit_ops argument and a 64-bit int from the top of the stack, and returns nothing (for instance, tsv setter). */ void (*emit_void_call_2) (CORE_ADDR fn, int arg1); + + /* Emit code specialized for common combinations of compare followed + by a goto. */ + void (*emit_eq_goto) (int *offset_p, int *size_p); + void (*emit_ne_goto) (int *offset_p, int *size_p); + void (*emit_lt_goto) (int *offset_p, int *size_p); + void (*emit_le_goto) (int *offset_p, int *size_p); + void (*emit_gt_goto) (int *offset_p, int *size_p); + void (*emit_ge_goto) (int *offset_p, int *size_p); }; /* Returns the address of the get_raw_reg function in the IPA. */ diff --git a/gdb/gdbserver/tracepoint.c b/gdb/gdbserver/tracepoint.c index 8cfb7730b6..0a64104072 100644 --- a/gdb/gdbserver/tracepoint.c +++ b/gdb/gdbserver/tracepoint.c @@ -483,6 +483,14 @@ static const char *gdb_agent_op_names [gdb_agent_op_last] = #undef DEFOP }; +static const unsigned char gdb_agent_op_sizes [gdb_agent_op_last] = + { + 0 +#define DEFOP(NAME, SIZE, DATA_SIZE, CONSUMED, PRODUCED, VALUE) , SIZE +#include "ax.def" +#undef DEFOP + }; + struct agent_expr { int length; @@ -5663,6 +5671,42 @@ emit_void_call_2 (CORE_ADDR fn, int arg1) target_emit_ops ()->emit_void_call_2 (fn, arg1); } +static void +emit_eq_goto (int *offset_p, int *size_p) +{ + target_emit_ops ()->emit_eq_goto (offset_p, size_p); +} + +static void +emit_ne_goto (int *offset_p, int *size_p) +{ + target_emit_ops ()->emit_ne_goto (offset_p, size_p); +} + +static void +emit_lt_goto (int *offset_p, int *size_p) +{ + target_emit_ops ()->emit_lt_goto (offset_p, size_p); +} + +static void +emit_ge_goto (int *offset_p, int *size_p) +{ + target_emit_ops ()->emit_ge_goto (offset_p, size_p); +} + +static void +emit_gt_goto (int *offset_p, int *size_p) +{ + target_emit_ops ()->emit_gt_goto (offset_p, size_p); +} + +static void +emit_le_goto (int *offset_p, int *size_p) +{ + target_emit_ops ()->emit_le_goto (offset_p, size_p); +} + static enum eval_result_type compile_bytecodes (struct agent_expr *aexpr); static void @@ -5712,6 +5756,30 @@ compile_tracepoint_condition (struct tracepoint *tpoint, *jump_entry += 16; } +/* Scan an agent expression for any evidence that the given PC is the + target of a jump bytecode in the expression. */ + +int +is_goto_target (struct agent_expr *aexpr, int pc) +{ + int i; + unsigned char op; + + for (i = 0; i < aexpr->length; i += 1 + gdb_agent_op_sizes[op]) + { + op = aexpr->bytes[i]; + + if (op == gdb_agent_op_goto || op == gdb_agent_op_if_goto) + { + int target = (aexpr->bytes[i + 1] << 8) + aexpr->bytes[i + 2]; + if (target == pc) + return 1; + } + } + + return 0; +} + /* Given an agent expression, turn it into native code. */ static enum eval_result_type @@ -5719,7 +5787,7 @@ compile_bytecodes (struct agent_expr *aexpr) { int pc = 0; int done = 0; - unsigned char op; + unsigned char op, next_op; int arg; /* This is only used to build 64-bit value for constants. */ ULONGEST top; @@ -5831,11 +5899,64 @@ compile_bytecodes (struct agent_expr *aexpr) break; case gdb_agent_op_equal: - emit_equal (); + next_op = aexpr->bytes[pc]; + if (next_op == gdb_agent_op_if_goto + && !is_goto_target (aexpr, pc) + && target_emit_ops ()->emit_eq_goto) + { + trace_debug ("Combining equal & if_goto"); + pc += 1; + aentry->pc = pc; + arg = aexpr->bytes[pc++]; + arg = (arg << 8) + aexpr->bytes[pc++]; + aentry->goto_pc = arg; + emit_eq_goto (&(aentry->from_offset), &(aentry->from_size)); + } + else if (next_op == gdb_agent_op_log_not + && (aexpr->bytes[pc + 1] == gdb_agent_op_if_goto) + && !is_goto_target (aexpr, pc + 1) + && target_emit_ops ()->emit_ne_goto) + { + trace_debug ("Combining equal & log_not & if_goto"); + pc += 2; + aentry->pc = pc; + arg = aexpr->bytes[pc++]; + arg = (arg << 8) + aexpr->bytes[pc++]; + aentry->goto_pc = arg; + emit_ne_goto (&(aentry->from_offset), &(aentry->from_size)); + } + else + emit_equal (); break; case gdb_agent_op_less_signed: - emit_less_signed (); + next_op = aexpr->bytes[pc]; + if (next_op == gdb_agent_op_if_goto + && !is_goto_target (aexpr, pc)) + { + trace_debug ("Combining less_signed & if_goto"); + pc += 1; + aentry->pc = pc; + arg = aexpr->bytes[pc++]; + arg = (arg << 8) + aexpr->bytes[pc++]; + aentry->goto_pc = arg; + emit_lt_goto (&(aentry->from_offset), &(aentry->from_size)); + } + else if (next_op == gdb_agent_op_log_not + && !is_goto_target (aexpr, pc) + && (aexpr->bytes[pc + 1] == gdb_agent_op_if_goto) + && !is_goto_target (aexpr, pc + 1)) + { + trace_debug ("Combining less_signed & log_not & if_goto"); + pc += 2; + aentry->pc = pc; + arg = aexpr->bytes[pc++]; + arg = (arg << 8) + aexpr->bytes[pc++]; + aentry->goto_pc = arg; + emit_ge_goto (&(aentry->from_offset), &(aentry->from_size)); + } + else + emit_less_signed (); break; case gdb_agent_op_less_unsigned: @@ -5946,7 +6067,38 @@ compile_bytecodes (struct agent_expr *aexpr) break; case gdb_agent_op_swap: - emit_swap (); + next_op = aexpr->bytes[pc]; + /* Detect greater-than comparison sequences. */ + if (next_op == gdb_agent_op_less_signed + && !is_goto_target (aexpr, pc) + && (aexpr->bytes[pc + 1] == gdb_agent_op_if_goto) + && !is_goto_target (aexpr, pc + 1)) + { + trace_debug ("Combining swap & less_signed & if_goto"); + pc += 2; + aentry->pc = pc; + arg = aexpr->bytes[pc++]; + arg = (arg << 8) + aexpr->bytes[pc++]; + aentry->goto_pc = arg; + emit_gt_goto (&(aentry->from_offset), &(aentry->from_size)); + } + else if (next_op == gdb_agent_op_less_signed + && !is_goto_target (aexpr, pc) + && (aexpr->bytes[pc + 1] == gdb_agent_op_log_not) + && !is_goto_target (aexpr, pc + 1) + && (aexpr->bytes[pc + 2] == gdb_agent_op_if_goto) + && !is_goto_target (aexpr, pc + 2)) + { + trace_debug ("Combining swap & less_signed & log_not & if_goto"); + pc += 3; + aentry->pc = pc; + arg = aexpr->bytes[pc++]; + arg = (arg << 8) + aexpr->bytes[pc++]; + aentry->goto_pc = arg; + emit_le_goto (&(aentry->from_offset), &(aentry->from_size)); + } + else + emit_swap (); break; case gdb_agent_op_getv: