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- Remove unnecessary jump instruction(s) when offset(s) is/are zero(s).

Browse Source 
- Constantly use conditional jumps for unsigned integers.
This commit is contained in:
Jung-uk Kim 2008-08-13 19:25:09 +00:00
parent ab46d66ac3
commit f40611e24f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=181697
4 changed files with 168 additions and 156 deletions
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79
sys/amd64/amd64/bpf_jit_machdep.c
View File

@ -159,7 +159,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
MOVrd(ECX, ESI);
ADDib(sizeof(int), ECX);
CMPrd(EDI, ECX);
JLEb(6);
JBEb(6);
ZEROrd(EAX);
MOVrq3(R8, RBX);
RET();
@ -173,7 +173,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
MOVrd(ECX, ESI);
ADDib(sizeof(short), ECX);
CMPrd(EDI, ECX);
JLEb(4);
JBEb(4);
MOVrq3(R8, RBX);
RET();
MOVobw(RBX, RSI, AX);
@ -184,7 +184,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
ZEROrd(EAX);
MOVid(ins->k, ECX);
CMPrd(EDI, ECX);
JLEb(4);
JBEb(4);
MOVrq3(R8, RBX);
RET();
MOVobb(RBX, RCX, AL);
@ -204,7 +204,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
MOVrd(ECX, ESI);
ADDib(sizeof(int), ECX);
CMPrd(EDI, ECX);
JLEb(6);
JBEb(6);
ZEROrd(EAX);
MOVrq3(R8, RBX);
RET();
@ -219,7 +219,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
MOVrd(ECX, ESI);
ADDib(sizeof(short), ECX);
CMPrd(EDI, ECX);
JLEb(4);
JBEb(4);
MOVrq3(R8, RBX);
RET();
MOVobw(RBX, RSI, AX);
@ -231,7 +231,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
MOVid(ins->k, ECX);
ADDrd(EDX, ECX);
CMPrd(EDI, ECX);
JLEb(4);
JBEb(4);
MOVrq3(R8, RBX);
RET();
MOVobb(RBX, RCX, AL);
@ -240,7 +240,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
case BPF_LDX|BPF_MSH|BPF_B:
MOVid(ins->k, ECX);
CMPrd(EDI, ECX);
JLEb(6);
JBEb(6);
ZEROrd(EAX);
MOVrq3(R8, RBX);
RET();
@ -293,70 +293,59 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
break;
case BPF_JMP|BPF_JGT|BPF_K:
if (ins->jt == 0 && ins->jf == 0)
break;
CMPid(ins->k, EAX);
/* 5 is the size of the following JMP */
JG(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc] + 5 );
JMP(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc]);
JCC(JA, JBE);
break;
case BPF_JMP|BPF_JGE|BPF_K:
if (ins->jt == 0 && ins->jf == 0)
break;
CMPid(ins->k, EAX);
JGE(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc] + 5);
JMP(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc]);
JCC(JAE, JB);
break;
case BPF_JMP|BPF_JEQ|BPF_K:
if (ins->jt == 0 && ins->jf == 0)
break;
CMPid(ins->k, EAX);
JE(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc] + 5);
JMP(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc]);
JCC(JE, JNE);
break;
case BPF_JMP|BPF_JSET|BPF_K:
MOVrd(EAX, ECX);
ANDid(ins->k, ECX);
JE(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc] + 5);
JMP(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc]);
if (ins->jt == 0 && ins->jf == 0)
break;
TESTid(ins->k, EAX);
JCC(JNE, JE);
break;
case BPF_JMP|BPF_JGT|BPF_X:
if (ins->jt == 0 && ins->jf == 0)
break;
CMPrd(EDX, EAX);
JA(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc] + 5);
JMP(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc]);
JCC(JA, JBE);
break;
case BPF_JMP|BPF_JGE|BPF_X:
if (ins->jt == 0 && ins->jf == 0)
break;
CMPrd(EDX, EAX);
JAE(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc] + 5);
JMP(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc]);
JCC(JAE, JB);
break;
case BPF_JMP|BPF_JEQ|BPF_X:
if (ins->jt == 0 && ins->jf == 0)
break;
CMPrd(EDX, EAX);
JE(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc] + 5);
JMP(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc]);
JCC(JE, JNE);
break;
case BPF_JMP|BPF_JSET|BPF_X:
MOVrd(EAX, ECX);
ANDrd(EDX, ECX);
JE(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc] + 5);
JMP(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc]);
if (ins->jt == 0 && ins->jf == 0)
break;
TESTrd(EDX, EAX);
JCC(JNE, JE);
break;
case BPF_ALU|BPF_ADD|BPF_X:
@ -374,7 +363,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
break;
case BPF_ALU|BPF_DIV|BPF_X:
CMPid(0, EDX);
TESTrd(EDX, EDX);
JNEb(6);
ZEROrd(EAX);
MOVrq3(R8, RBX);

83
sys/amd64/amd64/bpf_jit_machdep.h
View File

@ -294,6 +294,24 @@ typedef void (*emit_func)(bpf_bin_stream *stream, u_int value, u_int n);
(3 << 6) | ((sr32 & 0x7) << 3) | (dr32 & 0x7), 1); \
} while (0)
/* testl i32,r32 */
#define TESTid(i32, r32) do { \
if (r32 == EAX) { \
emitm(&stream, 0xa9, 1); \
} else { \
emitm(&stream, 0xf7, 1); \
emitm(&stream, (3 << 6) | r32, 1); \
} \
emitm(&stream, i32, 4); \
} while (0)
/* testl sr32,dr32 */
#define TESTrd(sr32, dr32) do { \
emitm(&stream, 0x85, 1); \
emitm(&stream, \
(3 << 6) | ((sr32 & 0x7) << 3) | (dr32 & 0x7), 1); \
} while (0)
/* orl sr32,dr32 */
#define ORrd(sr32, dr32) do { \
emitm(&stream, 0x09, 1); \
@ -369,42 +387,12 @@ typedef void (*emit_func)(bpf_bin_stream *stream, u_int value, u_int n);
emitm(&stream, off8, 1); \
} while (0)
/* je off32 */
#define JE(off32) do { \
emitm(&stream, 0x840f, 2); \
emitm(&stream, off32, 4); \
} while (0)
/* jle off8 */
#define JLEb(off8) do { \
emitm(&stream, 0x7e, 1); \
/* jbe off8 */
#define JBEb(off8) do { \
emitm(&stream, 0x76, 1); \
emitm(&stream, off8, 1); \
} while (0)
/* ja off32 */
#define JA(off32) do { \
emitm(&stream, 0x870f, 2); \
emitm(&stream, off32, 4); \
} while (0)
/* jae off32 */
#define JAE(off32) do { \
emitm(&stream, 0x830f, 2); \
emitm(&stream, off32, 4); \
} while (0)
/* jg off32 */
#define JG(off32) do { \
emitm(&stream, 0x8f0f, 2); \
emitm(&stream, off32, 4); \
} while (0)
/* jge off32 */
#define JGE(off32) do { \
emitm(&stream, 0x8d0f, 2); \
emitm(&stream, off32, 4); \
} while (0)
/* jmp off32 */
#define JMP(off32) do { \
emitm(&stream, 0xe9, 1); \
@ -417,4 +405,33 @@ typedef void (*emit_func)(bpf_bin_stream *stream, u_int value, u_int n);
emitm(&stream, (3 << 6) | ((r32 & 0x7) << 3) | (r32 & 0x7), 1); \
} while (0)
/*
* Conditional long jumps
*/
#define JB 0x82
#define JAE 0x83
#define JE 0x84
#define JNE 0x85
#define JBE 0x86
#define JA 0x87
#define JCC(t, f) do { \
if (ins->jt != 0 && ins->jf != 0) { \
/* 5 is the size of the following jmp */ \
emitm(&stream, ((t) << 8) | 0x0f, 2); \
emitm(&stream, stream.refs[stream.bpf_pc + ins->jt] - \
stream.refs[stream.bpf_pc] + 5, 4); \
JMP(stream.refs[stream.bpf_pc + ins->jf] - \
stream.refs[stream.bpf_pc]); \
} else if (ins->jt != 0) { \
emitm(&stream, ((t) << 8) | 0x0f, 2); \
emitm(&stream, stream.refs[stream.bpf_pc + ins->jt] - \
stream.refs[stream.bpf_pc], 4); \
} else { \
emitm(&stream, ((f) << 8) | 0x0f, 2); \
emitm(&stream, stream.refs[stream.bpf_pc + ins->jf] - \
stream.refs[stream.bpf_pc], 4); \
} \
} while (0)
#endif /* _BPF_JIT_MACHDEP_H_ */

79
sys/i386/i386/bpf_jit_machdep.c
View File

@ -166,7 +166,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
MOVrd(ECX, ESI);
ADDib(sizeof(int), ECX);
CMPrd(EDI, ECX);
JLEb(7);
JBEb(7);
ZEROrd(EAX);
POP(EBX);
POP(ESI);
@ -182,7 +182,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
MOVrd(ECX, ESI);
ADDib(sizeof(short), ECX);
CMPrd(EDI, ECX);
JLEb(5);
JBEb(5);
POP(EBX);
POP(ESI);
POP(EDI);
@ -195,7 +195,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
ZEROrd(EAX);
MOVid(ins->k, ECX);
CMPrd(EDI, ECX);
JLEb(5);
JBEb(5);
POP(EBX);
POP(ESI);
POP(EDI);
@ -217,7 +217,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
MOVrd(ECX, ESI);
ADDib(sizeof(int), ECX);
CMPrd(EDI, ECX);
JLEb(7);
JBEb(7);
ZEROrd(EAX);
POP(EBX);
POP(ESI);
@ -234,7 +234,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
MOVrd(ECX, ESI);
ADDib(sizeof(short), ECX);
CMPrd(EDI, ECX);
JLEb(5);
JBEb(5);
POP(EBX);
POP(ESI);
POP(EDI);
@ -248,7 +248,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
MOVid(ins->k, ECX);
ADDrd(EDX, ECX);
CMPrd(EDI, ECX);
JLEb(5);
JBEb(5);
POP(EBX);
POP(ESI);
POP(EDI);
@ -259,7 +259,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
case BPF_LDX|BPF_MSH|BPF_B:
MOVid(ins->k, ECX);
CMPrd(EDI, ECX);
JLEb(7);
JBEb(7);
ZEROrd(EAX);
POP(EBX);
POP(ESI);
@ -314,70 +314,59 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
break;
case BPF_JMP|BPF_JGT|BPF_K:
if (ins->jt == 0 && ins->jf == 0)
break;
CMPid(ins->k, EAX);
/* 5 is the size of the following JMP */
JG(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc] + 5 );
JMP(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc]);
JCC(JA, JBE);
break;
case BPF_JMP|BPF_JGE|BPF_K:
if (ins->jt == 0 && ins->jf == 0)
break;
CMPid(ins->k, EAX);
JGE(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc] + 5);
JMP(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc]);
JCC(JAE, JB);
break;
case BPF_JMP|BPF_JEQ|BPF_K:
if (ins->jt == 0 && ins->jf == 0)
break;
CMPid(ins->k, EAX);
JE(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc] + 5);
JMP(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc]);
JCC(JE, JNE);
break;
case BPF_JMP|BPF_JSET|BPF_K:
MOVrd(EAX, ECX);
ANDid(ins->k, ECX);
JE(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc] + 5);
JMP(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc]);
if (ins->jt == 0 && ins->jf == 0)
break;
TESTid(ins->k, EAX);
JCC(JNE, JE);
break;
case BPF_JMP|BPF_JGT|BPF_X:
if (ins->jt == 0 && ins->jf == 0)
break;
CMPrd(EDX, EAX);
JA(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc] + 5);
JMP(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc]);
JCC(JA, JBE);
break;
case BPF_JMP|BPF_JGE|BPF_X:
if (ins->jt == 0 && ins->jf == 0)
break;
CMPrd(EDX, EAX);
JAE(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc] + 5);
JMP(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc]);
JCC(JAE, JB);
break;
case BPF_JMP|BPF_JEQ|BPF_X:
if (ins->jt == 0 && ins->jf == 0)
break;
CMPrd(EDX, EAX);
JE(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc] + 5);
JMP(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc]);
JCC(JE, JNE);
break;
case BPF_JMP|BPF_JSET|BPF_X:
MOVrd(EAX, ECX);
ANDrd(EDX, ECX);
JE(stream.refs[stream.bpf_pc + ins->jf] -
stream.refs[stream.bpf_pc] + 5);
JMP(stream.refs[stream.bpf_pc + ins->jt] -
stream.refs[stream.bpf_pc]);
if (ins->jt == 0 && ins->jf == 0)
break;
TESTrd(EDX, EAX);
JCC(JNE, JE);
break;
case BPF_ALU|BPF_ADD|BPF_X:
@ -395,7 +384,7 @@ bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
break;
case BPF_ALU|BPF_DIV|BPF_X:
CMPid(0, EDX);
TESTrd(EDX, EDX);
JNEb(7);
ZEROrd(EAX);
POP(EBX);

83
sys/i386/i386/bpf_jit_machdep.h
View File

@ -244,6 +244,24 @@ typedef void (*emit_func)(bpf_bin_stream *stream, u_int value, u_int n);
(3 << 6) | ((sr32 & 0x7) << 3) | (dr32 & 0x7), 1); \
} while (0)
/* testl i32,r32 */
#define TESTid(i32, r32) do { \
if (r32 == EAX) { \
emitm(&stream, 0xa9, 1); \
} else { \
emitm(&stream, 0xf7, 1); \
emitm(&stream, (3 << 6) | r32, 1); \
} \
emitm(&stream, i32, 4); \
} while (0)
/* testl sr32,dr32 */
#define TESTrd(sr32, dr32) do { \
emitm(&stream, 0x85, 1); \
emitm(&stream, \
(3 << 6) | ((sr32 & 0x7) << 3) | (dr32 & 0x7), 1); \
} while (0)
/* orl sr32,dr32 */
#define ORrd(sr32, dr32) do { \
emitm(&stream, 0x09, 1); \
@ -319,42 +337,12 @@ typedef void (*emit_func)(bpf_bin_stream *stream, u_int value, u_int n);
emitm(&stream, off8, 1); \
} while (0)
/* je off32 */
#define JE(off32) do { \
emitm(&stream, 0x840f, 2); \
emitm(&stream, off32, 4); \
} while (0)
/* jle off8 */
#define JLEb(off8) do { \
emitm(&stream, 0x7e, 1); \
/* jbe off8 */
#define JBEb(off8) do { \
emitm(&stream, 0x76, 1); \
emitm(&stream, off8, 1); \
} while (0)
/* ja off32 */
#define JA(off32) do { \
emitm(&stream, 0x870f, 2); \
emitm(&stream, off32, 4); \
} while (0)
/* jae off32 */
#define JAE(off32) do { \
emitm(&stream, 0x830f, 2); \
emitm(&stream, off32, 4); \
} while (0)
/* jg off32 */
#define JG(off32) do { \
emitm(&stream, 0x8f0f, 2); \
emitm(&stream, off32, 4); \
} while (0)
/* jge off32 */
#define JGE(off32) do { \
emitm(&stream, 0x8d0f, 2); \
emitm(&stream, off32, 4); \
} while (0)
/* jmp off32 */
#define JMP(off32) do { \
emitm(&stream, 0xe9, 1); \
@ -367,4 +355,33 @@ typedef void (*emit_func)(bpf_bin_stream *stream, u_int value, u_int n);
emitm(&stream, (3 << 6) | ((r32 & 0x7) << 3) | (r32 & 0x7), 1); \
} while (0)
/*
* Conditional long jumps
*/
#define JB 0x82
#define JAE 0x83
#define JE 0x84
#define JNE 0x85
#define JBE 0x86
#define JA 0x87
#define JCC(t, f) do { \
if (ins->jt != 0 && ins->jf != 0) { \
/* 5 is the size of the following jmp */ \
emitm(&stream, ((t) << 8) | 0x0f, 2); \
emitm(&stream, stream.refs[stream.bpf_pc + ins->jt] - \
stream.refs[stream.bpf_pc] + 5, 4); \
JMP(stream.refs[stream.bpf_pc + ins->jf] - \
stream.refs[stream.bpf_pc]); \
} else if (ins->jt != 0) { \
emitm(&stream, ((t) << 8) | 0x0f, 2); \
emitm(&stream, stream.refs[stream.bpf_pc + ins->jt] - \
stream.refs[stream.bpf_pc], 4); \
} else { \
emitm(&stream, ((f) << 8) | 0x0f, 2); \
emitm(&stream, stream.refs[stream.bpf_pc + ins->jf] - \
stream.refs[stream.bpf_pc], 4); \
} \
} while (0)
#endif /* _BPF_JIT_MACHDEP_H_ */