The frame object is inside the "frame" variable you defined. To get the local variables for a frame object, you can call its f_locals attribute like this:
import inspect
class Debug:
def __init__(self):
frames = inspect.stack()
for frame in frames:
line = frame.code_context[0]
if "Debug" in line:
break
# I want to get the locals() at the time debug was called here!
# give me i_will_be_in_the_locals
from pprint
import pprint
pprint(frame.frame.f_locals)
def __enter__(self):
pass
def __exit__(self, exc_type, exc_val, exc_tb):
pass
if __name__ == "__main__":
i_will_be_in_the_locals = 42
with Debug():
"hi"The returned value is:
{'Debug': <class '__main__.Debug'>,
'__builtins__': <module 'builtins' (built-in)>,
'__cached__': None,
'__doc__': None,
'__file__': '/home/user1/main-projects/overflow/file.py',
'__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x7f7bbb44f7f0>,
'__name__': '__main__',
'__package__': None,
'__spec__': None,
'i_will_be_in_the_locals': 42,
'inspect': <module 'inspect' from '/usr/lib/python3.5/inspect.py'>}
I have a debug context manager where I would anycodings_python like to access the locals() at the time the anycodings_python context manager was initiated, without anycodings_python giving the locals as an argument. Is this anycodings_python possible?,Mutate a column that contains whether both variables or just one variables are present in another columns,I would like to do this in the general case, anycodings_python so that my Debug context manager can be used anycodings_python from any file importing Debug, not just in anycodings_python the tinkertoy example below. ,Python iterate over each individual list that is stored in a variable and make it as single list
Here is my minimal example:
import inspect
class Debug:
def __init__(self):
frames = inspect.stack()
for frame in frames:
line = frame.code_context[0]
if "Debug" in line:
break
# I want to get the locals() at the time debug was called here!
# give me i_will_be_in_the_locals
raise Exception()
def __enter__(self):
pass
def __exit__(self, exc_type, exc_val, exc_tb):
pass
if __name__ == "__main__":
i_will_be_in_the_locals = 42
with Debug():
"hi"The frame object is inside the "frame" anycodings_contextmanager variable you defined. To get the local anycodings_contextmanager variables for a frame object, you can anycodings_contextmanager call its f_locals attribute like this:
import inspect
class Debug:
def __init__(self):
frames = inspect.stack()
for frame in frames:
line = frame.code_context[0]
if "Debug" in line:
break
# I want to get the locals() at the time debug was called here!
# give me i_will_be_in_the_locals
from pprint
import pprint
pprint(frame.frame.f_locals)
def __enter__(self):
pass
def __exit__(self, exc_type, exc_val, exc_tb):
pass
if __name__ == "__main__":
i_will_be_in_the_locals = 42
with Debug():
"hi"The returned value is:
{'Debug': <class '__main__.Debug'>,
'__builtins__': <module 'builtins' (built-in)>,
'__cached__': None,
'__doc__': None,
'__file__': '/home/user1/main-projects/overflow/file.py',
'__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x7f7bbb44f7f0>,
'__name__': '__main__',
'__package__': None,
'__spec__': None,
'i_will_be_in_the_locals': 42,
'inspect': <module 'inspect' from '/usr/lib/python3.5/inspect.py'>}
Last updated: February 16, 2018
Let’s consider the following set of functions in a file called try.c
void
bar(int a, int b) {
int x, y;
x = 555;
y = a + b;
}
void
foo(void) {
bar(111, 222);
}We’ll compile it via
gcc - S - m32
try.cThe generated code is (removing lines that contain directives to the linker):
bar:
pushl % ebp
movl % esp, % ebp
subl $16, % esp
movl $555, -4( % ebp)
movl 12( % ebp), % eax
movl 8( % ebp), % edx
addl % edx, % eax
movl % eax, -8( % ebp)
leave
ret
foo:
pushl % ebp
movl % esp, % ebp
subl $8, % esp
movl $222, 4( % esp)
movl $111, ( % esp)
call bar
leave
retLet’s see what happens. In foo(), we need to prepare the stack for two parameters that will be sent to bar(). The compiler would like to do
push $222 push $111
Last Updated : 15 Jun, 2021,GATE CS 2021 Syllabus
Output :
Product is: 36 Sum is: 12
The location in the stack frame for storing the input character is computed relative to the frame pointer:, The second instruction pops two values off the top of the stack into: the frame pointer, and the link register. This restores the calling function's value in the frame pointer and return address. ,This instruction subtracts \(5\) from the address in the frame pointer register and stores the result in register r3, ready to be passed to the read function.,It is important to understand that although you know the values above the stack pointer (the gray area in Figure 10.5.4) are probably still in memory, attempting to access them is a violation of stack protocol.
.arch armv6
.file "echoChar1.c"
.section.rodata
.align 2
.LC0:
.ascii "Enter one character: \000"
.align 2
.LC1:
.ascii "You entered: \000"
.text
.align 2
.global main
.syntax unified
.arm
.fpu vfp
.type main, % function
main:
@ args = 0, pretend = 0, frame = 8
@ frame_needed = 1, uses_anonymous_args = 0
push {
fp,
lr
}
add fp, sp, #4 @@ set up our frame pointer
sub sp, sp, # 8 @ @ allocate memory
for local
var
mov r2, #21
ldr r1, .L3
mov r0, # 1
bl write @ @ prompt user
for input
sub r3, fp, #5 @@ compute address
mov r2, # 1 @ @ one char
mov r1, r3 @ @ address
for storing input char
mov r0, #0 @@ standard in (keyboard)
bl read
mov r2, # 13 @ @ nice message to user
ldr r1, .L3 + 4
mov r0, #1
bl write
sub r3, fp, # 5 @ @ address where char was stored
mov r2, #1
mov r1, r3
mov r0, # 1
bl write
mov r3, #0
mov r0, r3
sub sp, fp, # 4 @ @ deallocate local
var
@ sp needed
pop {
fp,
pc
}
.L4:
.align 2
.L3:
.word.LC0
.word.LC1
.size main, . - main
.ident "GCC: (Raspbian 6.3.0-18+rpi1) 6.3.0 20170516"sub sp, sp, #8 @@ allocate memory for local var
sub r3, fp, #5 @@ compute address
@ echoChar2.s @ Prompts user to enter a character and echoes it. @ 2017 - 09 - 29: Bob Plantz @ Define my Raspberry Pi .cpu cortex - a53 .fpu neon - fp - armv8 .syntax unified @ modern syntax @ Useful source code constants .equ STDIN, 0 .equ STDOUT, 1 .equ aLetter, -5 .equ local, 8 @ Constant program data .section.rodata .align 2 promptMsg: .asciz "Enter one character: " .equ promptLngth, . - promptMsg responseMsg: .asciz "You entered: " .equ responseLngth, . - responseMsg @ Program code .text .align 2 .global main .type main, % function main: sub sp, sp, 8 @ space for fp, lr str fp, [sp, 0] @ save fp str lr, [sp, 4] @ and lr add fp, sp, 4 @ set our frame pointer sub sp, sp, local @ allocate memory for local var mov r0, STDOUT @ prompt user for input ldr r1, promptMsgAddr mov r2, promptLngth bl write mov r0, STDIN @ from keyboard add r1, fp, aLetter @ address of aLetter mov r2, 1 @ one char bl read mov r0, STDOUT @ nice message for user ldr r1, responseMsgAddr mov r2, responseLngth bl write mov r0, STDOUT @ echo user 's character add r1, fp, aLetter @ address of aLetter mov r2, 1 @ one char bl write mov r0, 0 @ return 0; add sp, sp, local @ deallocate local var ldr fp, [sp, 0] @ restore caller fp ldr lr, [sp, 4] @ lr add sp, sp, 8 @ and sp bx lr @ return @ Addresses of messages .align 2 promptMsgAddr: .word promptMsg responseMsgAddr: .word responseMsg
.equ STDIN, 0 .equ STDOUT, 1 .equ aLetter, -5 .equ locals, 8
add r1, fp, aLetter @ address of aLetter
Each time your program performs a function call, the information about where in your program the call was made from is saved in a block of data called a stack frame. The frame also contains the arguments of the call and the local variables of the function that was called. All the stack frames are allocated in a region of memory called the call stack. , The call stack is divided up into contiguous pieces called stack frames, or frames for short; each frame is the data associated with one call to one function. The frame contains the arguments given to the function, the function's local variables, and the address at which the function is executing. , All of these commands end by printing two lines of output describing the frame. The first line shows the frame number, the function name, the arguments, and the source file and line number of execution in that frame. The second line shows the text of that source line. , There are several other commands to print information about the selected stack frame.
#0 m4_traceon (obs= 0x24eb0, argc = 1, argv = 0x2b8c8) at builtin.c: 993 #1 0x6e38 in expand_macro (sym= 0x2b600) at macro.c: 242 #2 0x6840 in expand_token (obs= 0x0, t = 177664, td = 0xf7fffb08) at macro.c: 71(More stack frames follow...)
StackFrames provide access to a method's local variables and their current values. , The lifetime of a StackFrame is very limited. It is available only for suspended threads and becomes invalid once its thread is resumed. , Any method on StackFrame which takes StackFrame as an parameter may throw VMDisconnectedException if the target VM is disconnected and the VMDisconnectEvent has been or is available to be read from the EventQueue. , Visibility is based on the code index of the current instruction of this StackFrame. Each variable has a range of byte code indices in which it is accessible. If this stack frame's method matches this variable's method and if the code index of this StackFrame is within the variable's byte code range, the variable is visible.
@Exported
public interface StackFrame
extends Mirror, Locatablelocation
Location location()
thread
ThreadReference thread()
thisObject
ObjectReference thisObject()
visibleVariables
List<LocalVariable> visibleVariables()
throws AbsentInformationExceptionvisibleVariableByName
LocalVariable visibleVariableByName(String name)
throws AbsentInformationException