如何查看v8生成的机器代码? [英] How can I see the machine code generated by v8?
问题描述
有谁知道我如何看到 v8 从Javascript生成的实际机器代码?我已经在 src / api.cc
中获得 Script :: Compile()
,但我不能找出从那里去的地方。
Does anybody know how I can see the actual machine code that v8 generates from Javascript? I've gotten as far as Script::Compile()
in src/api.cc
but I can't figure out where to go from there.
推荐答案
我不知道如何从C ++代码调用反汇编程序,但是有从shell中获取反汇编的快捷方法。
I don't know how to invoke the disassembler from C++ code, but there is a quick-and-dirty way to get a disassembly from the shell.
首先,使用反汇编程序支持编译v8:
First, compile v8 with disassembler support:
scons [your v8 build options here] disassembler=on sample=shell
现在你可以使用--print_code选项调用shell:
Now you can invoke the shell with the "--print_code" option:
./shell --print_code hello.js
这应该给你这样的东西:
Which should give you something like this:
--- Raw source ---
print("hello world");
--- Code ---
kind = FUNCTION
Instructions (size = 134)
0x2ad0a77ceea0 0 55 push rbp
0x2ad0a77ceea1 1 488bec REX.W movq rbp,rsp
0x2ad0a77ceea4 4 56 push rsi
0x2ad0a77ceea5 5 57 push rdi
0x2ad0a77ceea6 6 49ba59c13da9d02a0000 REX.W movq r10,0x2ad0a93dc159 ;; object: 0xa93dc159 <undefined>
0x2ad0a77ceeb0 16 4952 REX.W push r10
0x2ad0a77ceeb2 18 49ba688b700000000000 REX.W movq r10,0x708b68
0x2ad0a77ceebc 28 493b22 REX.W cmpq rsp,[r10]
0x2ad0a77ceebf 31 0f824e000000 jc 115 (0x2ad0a77cef13)
0x2ad0a77ceec5 37 488b462f REX.W movq rax,[rsi+0x2f]
0x2ad0a77ceec9 41 4883ec18 REX.W subq rsp,0xlx
0x2ad0a77ceecd 45 49ba094b3ea9d02a0000 REX.W movq r10,0x2ad0a93e4b09 ;; object: 0xa93e4b09 <String[5]: print>
0x2ad0a77ceed7 55 4c8955e0 REX.W movq [rbp-0x20],r10
0x2ad0a77ceedb 59 488945d8 REX.W movq [rbp-0x28],rax
0x2ad0a77ceedf 63 49ba014d3ea9d02a0000 REX.W movq r10,0x2ad0a93e4d01 ;; object: 0xa93e4d01 <String[11]: hello world>
0x2ad0a77ceee9 73 4c8955d0 REX.W movq [rbp-0x30],r10
0x2ad0a77ceeed 77 49baa06c7ba7d02a0000 REX.W movq r10,0x2ad0a77b6ca0 ;; debug: statement 0
;; code: contextual, CALL_IC, UNINITIALIZED, argc = 1
0x2ad0a77ceef7 87 49ffd2 REX.W call r10
0x2ad0a77ceefa 90 488b75f8 REX.W movq rsi,[rbp-0x8]
0x2ad0a77ceefe 94 4883c408 REX.W addq rsp,0xlx
0x2ad0a77cef02 98 488945e8 REX.W movq [rbp-0x18],rax
0x2ad0a77cef06 102 488be5 REX.W movq rsp,rbp ;; js return
0x2ad0a77cef09 105 5d pop rbp
0x2ad0a77cef0a 106 c20800 ret 0x8
0x2ad0a77cef0d 109 cc int3
0x2ad0a77cef0e 110 cc int3
0x2ad0a77cef0f 111 cc int3
0x2ad0a77cef10 112 cc int3
0x2ad0a77cef11 113 cc int3
0x2ad0a77cef12 114 cc int3
0x2ad0a77cef13 115 49ba60657ba7d02a0000 REX.W movq r10,0x2ad0a77b6560 ;; code: STUB, StackCheck, minor: 0
0x2ad0a77cef1d 125 49ffd2 REX.W call r10
0x2ad0a77cef20 128 488b7df0 REX.W movq rdi,[rbp-0x10]
0x2ad0a77cef24 132 eb9f jmp 37 (0x2ad0a77ceec5)
RelocInfo (size = 10)
0x2ad0a77ceea8 embedded object (0xa93dc159 <undefined>)
0x2ad0a77ceecf embedded object (0xa93e4b09 <String[5]: print>)
0x2ad0a77ceee1 embedded object (0xa93e4d01 <String[11]: hello world>)
0x2ad0a77ceeed statement position (0)
0x2ad0a77ceeef code target (context) (CALL_IC) (0x2ad0a77b6ca0)
0x2ad0a77cef06 js return
0x2ad0a77cef15 code target (STUB) (0x2ad0a77b6560)
hello world
当然,你的输出会有所不同。以上是为Linux x64编译的v8 trunk。
Your output will vary, of course. The above is from the v8 trunk compiled for Linux x64.
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