98 lines
3.0 KiB
ArmAsm
98 lines
3.0 KiB
ArmAsm
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/**
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#include "RCTDefines.h"
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#include "RCTMacros.h"
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#if RCT_PROFILE && defined(__i386__)
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.globl SYMBOL_NAME(RCTProfileTrampoline)
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SYMBOL_NAME(RCTProfileTrampoline):
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/**
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* The x86 version is much simpler, since all the arguments are passed in the
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* stack, so we just have to preserve the stack pointer (%esp) and the callee
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* saved register used to keep the memory allocated
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*
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* The explanation here is also shorter, refer to the x86_64 implementation to
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* a richer explanation
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*/
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/**
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* Allocate memory to save the caller of RCTProfileTrampoline (used afterwards
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* to return at the end of the function) and the initial value for the callee
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* saved register (%edi) that will be used to point to the memory allocated.
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*/
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subl $0x8, %esp // stack padding (16-byte alignment for function calls)
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pushl $0xc // allocate 12-bytes
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calll SYMBOL_NAME(RCTProfileMalloc)
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addl $0xc, %esp // restore stack (8-byte padding + 4-byte argument)
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/**
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* actually store the values in the memory allocated
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*/
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movl %edi, 0x0(%eax) // previous value of edi
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popl 0x4(%eax) // caller of RCTProfileTrampoline
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// save the pointer to the allocated memory in %edi
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movl %eax, %edi
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/**
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* void RCTProfileGetImplementation(id object, SEL selector) in RCTProfile.m
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*
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* Get the address of the actual C function we have to profile
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*/
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calll SYMBOL_NAME(RCTProfileGetImplementation)
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movl %eax, 0x8(%edi) // Save it in the allocated memory
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/**
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* void RCTProfileTrampolineStart(id, SEL) in RCTProfile.m
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*
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* start profile - the arguments are already in the right position in the
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* stack since it takes the same first 2 arguments as the any ObjC function -
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* "self" and "_cmd"
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*/
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calll SYMBOL_NAME(RCTProfileTrampolineStart)
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/**
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* Call the actual function and save it's return value, since it should be the
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* return value of RCTProfileTrampoline
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*/
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calll *0x8(%edi)
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pushl %eax
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// Align stack and end profile
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subl $0xc, %esp
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calll SYMBOL_NAME(RCTProfileTrampolineEnd)
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addl $0xc, %esp // restore the stack
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/**
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* Move the values from the allocated memory to the stack, restore the
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* value of %edi, and prepare to free the allocated memory.
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*/
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pushl 0x4(%edi) // caller of RCTProfileTrampoline
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subl $0x4, %esp // Stack padding
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pushl %edi // push the memory address
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movl 0x0(%edi), %edi // restore the value of %edi
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/**
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* Actually free the memory used to store the values across function calls,
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* the stack has already been padded and the first and only argument, the
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* memory address, is already in the bottom of the stack.
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*/
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calll SYMBOL_NAME(RCTProfileFree)
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addl $0x8, %esp
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/**
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* pop the caller address to %ecx and the actual function return value to
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* %eax, so it's the return value of RCTProfileTrampoline
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*/
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popl %ecx
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popl %eax
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jmpl *%ecx
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#endif
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