Position independent code gcc Mar 9, 2023 · b. 什么是 Position Independent Code Position-independent code (PIC) is code that uses no hard-coded addresses for either code or data. Why? Because the displacement of the mov (the part that's added to rip) must fit in 32 bits, and when a code gets into a shared library, we just can't know in advance that 32 bits will be enough. When doing compilation directly via GCC, position independent code is specified as follows These helper functions are used by GCC and Clang in 32-bit x86 position-independent code to get the current execution address into a register, for example: call __i686. This enables one to share built library which has dependencies on other shared libraries. Sep 8, 2023 · I am trying to write a position independent firmware for an stm32 arm-cortex microcontroller compiled with gcc. The loader has to fix up the code references to that BSS address. Improve this question. soposition-independent code (PIC)：用于生成位置无关代码。位置无关代码，可以理解为代码无绝对跳转，跳转都为相对跳转。生成动态库时，需要加上-fPIC选项。 Apr 27, 2017 · Oh I see. This works fine for my C code. Rather, the use of a PLT in position-independent shared library code was instituted to exploit another property of having a PLT: lazy binding. Here's my code: int foo = 1; int main() { return &foo; } And I'm compiling it with something like: Jun 10, 2022 · position-independent-code; arm-none-eabi-gcc; or ask your own question. Also, It's easy to generate a . What is Position Independent Code (PIC)? Mar 15, 2017 · Код, не зависящий от адреса (position-independent code (PIC)). c -o liberr. It does malloc() for the BSS and zeroes it, for example. /Lib. Position-independent code-wiki; 深入理解 Linux 位置无关代码 PIC; Position Independent Code (PIC) in Jan 5, 2013 · By enabling Position Independent Code (PIC, with the flag -fPIC) you can ensure the code remains share-able. In this article, we will delve into the world of PIC (Position Independent Code) and illustrate its significance with a concise example. Apr 21, 2013 · gcc -m32 -e nomain -nostartfiles -fno-builtin -o a. GCC -fPIC Option. "call" for relative jump and "jmpl" for absolute jump. o as position-independent code, because it will be included into a shared library? At least on the system I'm testing it on, it seems to work fine when the first -fPIC is removed. To avoid it, I have to add -no-pie flag explicitly. PIC不使用绝对地址对data或者fun进行寻址，而是利用一些相对地址的手段进行，PIC一般而言是针对共享库的。 4. Such code accesses all constant addresses through a global offset table (GOT). Jul 11, 2024 · position_independent_code. The Program works fine as a stand alone on CC2650 (M3). Everything is working fine except global variables. cpp Then I generated an image with: Apr 8, 2017 · 2. This tells gcc to avoid using absolute addresses and include link time information to decouple the binary from a predetermined location in memory. The target is bare-metal risc-v, so no OS, no dynamic loader. Mar 17, 2010 · After enabling PIE support in gcc/linkers, the body of program is compiled and linked as position-independent code. 0x1 何为地址无关代码. When you make PIC code, it's not only the code that's position independent, it's the data as well. 4 20140725 My goal is to build an image that can be run from any properly-aligned offset in internal flash (i. A dynamic linker does full relocation processing on the program module, just like dynamic libraries. I wonder whether gcc have some option to genernate position-dependent for executable file? Feb 2, 2018 · Still not good. It is generated with the -fpic flag to gcc. Maybe try gcc 10 for good measure? Maybe it's mistakenly assuming a function pointer (which refers to a pure section) stored in an impure section is impure. bx addl $ gcc assembly Aug 28, 2020 · PIC，全称Position Independent Code。位置无关代码是指代码无论被加载到哪个地址上都可以正常执行。gcc选项中添加-fPIC会产生相关代码。关键点#1 - 代码段和数据段的偏移. a), the text of the library can be shared whether or not the library is linked at the same address for both programs. Aug 2, 2010 · It is a code model issues. Aug 5, 2024 · The -pie option generates a dynamically linked position-independent executable. Nov 8, 2023 · Position-independent code (PIC) is a type of code that can be executed at any memory address without modification. Jun 20, 2021 · However the GNU ARM Embedded compiler in version 9. c -o pie_not -no-pie And the generated ELF header is like this: pie_not: 6 如何使gcc默认使用-march=native选项？ 4 为什么gcc默认使用“-z now”链接选项，尽管ld默认使用懒绑定？ 13 如何确定gcc默认传递给ld的命令行选项？ 5 如何覆盖默认的gcc选项以链接程序？ 3 为什么C11标准不是gcc的默认选项？ 18 默认启用了gcc 4. Instead, GCC/ld use "position-independent" as a name for their very specific implementation of position-independent dynamic linking that involves global offset tables (GOTs) and special relocations to make sure this all works even if you have multiple position-independent libraries that need to get dynamically linked into multiple processes at 15 为什么gcc强制在x64共享库中使用PIC？ 4 如何强制GCC警告使用类函数？ 8 在GCC中调用汇编代码？ 16 使用GCC的内联汇编进行直接C函数调用; 8 强制GCC在memset()调用中使用重复前缀; 77 如何强制gcc内联函数？ 8 PIC（位置无关代码） 12 如何强制GCC编译未被使用的函数？ A 64-bit, position-independent code reverse TCP shell for Windows — built in Rust. This is the result of objdump -r on a file compiled with -fPIC : Aug 6, 2005 · As for actual position independent code on x86: since there isn't EIP-relative data-addressing, some tricks are needed. The GNU compiler (GCC) has a dedicated option to generate position independent code: Aug 6, 2005 · As for actual position independent code on x86: since there isn't EIP-relative data-addressing, some tricks are needed. 3. This is all being developed for an M4 processor in Eclipse, using the ARM GCC toolchain. The Feb 26, 2024 · This article explores the concept of Position-Independent Code (PIC) and Relative Data Access (RDA) in the context of the GNU Compiler Collection (GCC). It cannot assume … Position-independent code Read More » Feb 26, 2024 · I compiled the example code to an ELF with: # Using -g and -O0 so we can have a readable disassembly. 位置独立コード（いちどくりつコード、英: position-independent code 、PIC）または位置独立実行形式（いちどくりつじっこうけいしき、英: position-independent executable 、PIE）とは、主記憶装置内のどこに置かれても絶対アドレスに関わらず正しく実行できる機械語の列である。 Jun 5, 2021 · Visual Studio Code for C/C++ with ARM Cortex-M: Part 1 - Installation; Building with CMake Presets; Debugging STM32F103RB NUCLEO Board with Segger J-Link; Zooming In and Out of Text with Eclipse; Tutorial: Using GNU Profiling (gprof) with ARM Cortex-M; Unlocking and Erasing FLASH with Segger J-Link; Position-Independent Code with GCC for ARM Jun 5, 2021 · -fPIC 作用于编译阶段，告诉编译器产生与位置无关代码(Position-Independent Code)，则产生的代码中，没有绝对地址，全部使用相对地址，故而代码可以被加载器加载到内存的任意位置，都可以正确的执行。 You may have some luck with this answer, although it's platform dependent and doesn't work for all object files (but if you code manipulates pointers in any way, it should work). For Example a shellcode is PIC. fPIC stands for "force Position Independent Code". reverse-shell rust-lang redteam position-independent-code. Position-independent code (PIC) is a very old thing (in computer science terms, of course). I think before revealing the nitty-gritty details of this domain, I can give readers an overview about things. The sparc v8 Instruction set has two instructions for jumping. 31 has an issue preventing properly PIC code for M33 (warning: thumb-1 mode PLT generation not currently supported). Shared libraries produce position independent machine code. Aug 22, 2019 · Thankfully this is a problem that’s had a solution for a long time. Aug 22, 2022 · I'm working on a ARM bare metal binary, and I'm trying to get a fully position independent binary. 定义 -fpic 参数最直接的方式是通过cmake_cxx_flags或cmake_c_flags参数定义, 示例如下，因为它只是clang和gcc才有的参数所以在设置-fpic参数的时候需要判断编译器 Generate position-independent code (PIC) suitable for use in a shared library, if supported for the target machine. By generating position-independent code, when two different programs (A and B) share a common library (libC. plt sections. Oct 17, 2017 · I need a position independent code (PIC) working on STM32F401. Even though code compiles it still generates pic code. Nov 7, 2022 · 概念可以加载而无需重定位的代码称为位置无关代码（Position-Independent Code, IPC）,指代码无论被加载到哪个地址上都可以正常执行。gcc 选项中添加-fPIC会产生相关代码。PIC 用于共享库，允许库代码位于内存中的任何位置。 May 30, 2021 · In computing, position-independent code (PIC) or position-independent executable (PIE) is a body of machine code that, being placed somewhere in the primary memory, executes properly regardless of its absolute address. I found the following set of gcc flags that achieves this goal: # Generate position independent code. got or . I was wondering: if I generate a hex file through gcc using -fPIC, I producePosition Independent Code. Feb 24, 2023 · We have a bunch of C code that needs to be compiled as position independent code on an embedded system (Cortex-M7). Updated Jan 3, 2025;. 8. Apr 20, 2022 · Dear nxp community, I am having a hard time getting progress with position independent code and I hope somebody can find the time to help and explain some bits and pieces. bin file from an elf file with some tools. Jun 5, 2021 · Welcome to 'Alice in Wonderland'! For a university research project using an ARM Cortex-M33 we are evaluating position-independent code as way to load applications or part of it with a bootloader. For the x86, GCC supports PIC for System V but not for the Sun 386i. PIC means that the output binary does not expect to be loaded at a particular base address, but is happy being put anywhere in memory (compare the output of readelf --segments on a binary such as /bin/ls to that of any shared library). Position-independent code and Shared Libraries. 参考资料. Position-independent code is code that can be loaded anywhere in memory, without relocation. by using relative addressing. fPIC option in GCC enables the address of shared libraries to be relative so that the executable is independent of the position of libraries. PIE(Position Independent Executable)はプログラムをロードするアドレスが固定ではない実行ファイルです。OSはロードアドレスをランダム化することで安全性を上げることができます。 Aug 31, 2013 · I am trying to make these apps position independent so that they both can be compiled for the same base address. Under GCC, the first trick is to enable position-independent code [1] using the -fpic compiler flag. But i have problem with pointers to functions used e. Apr 3, 2012 · Turns out GCC adds a 'code veneer' when calling shared library functions and takes a detour when the function is called and doesn't actually branch to the address of the function. Jan 11, 2020 · I understand that the current gcc compilers by default generate position independent code. so position-independent code (PIC)：用于生成位置无关代码。位置无关代码，可以理解为代码无绝对跳转，跳转都为相对跳转。 MCU: STM32F4 (ARM Cortex M4) Build environment: arm-none-eabi-gcc 4. It seems gcc use -pie by default. The position-independent code is an important concept in modern computing, especially for systems where dynamic loading and address-space-layout-randomization (ASLR) are used for May 5, 2020 · The linker option -fPIC turns out to signify position independent code, a type of executable format that is typically associated with shared libraries. And not all code or data can be addressed simply by GNU Compiler Collection (GCC) Internals. А сейчас рассмотрим второй подход – PIC. Dec 15, 2014 · 文章浏览阅读2. Jul 6, 2015 · Posted on July 06, 2015 at 04:18 MCU: STM32F4 (ARM Cortex M4) Build environment: arm-none-eabi-gcc 4. All branches, and data references, are described in terms of offsets from %rip. 7k次，点赞3次，收藏3次。-fPIC 作用于编译阶段，告诉编译器产生与位置无关代码(Position-Independent Code)，则产生的代码中，没有绝对地址，全部使用相对地址，故而代码可以被加载器加载到内存的任意位置，都可以正确的执行。这正是共享库所要求的，共享库被加载时，在内存的位置不 Feb 7, 2025 · I am trying to build a static position-independent executable with gcc provided option -static-pie. This option makes a difference on AArch64, m68k, PowerPC and SPARC. ”-mpic-register=r9 Dec 18, 2024 · GCC (GNU Compiler Collection) provides various options to enhance code compatibility, one of which is the enigmatic "-fPIC" option. For the 386, GCC supports PIC for System V but not for the Sun 386i. I guess I figured it out. To get current EIP, one can near-call to next instruction, so as to push the "return address". Now we need to do the same under GCC (12. What is Position-Independent Code (PIC) on ARM 可以加载而无需重定位的代码称为位置无关代码（Position-Independent Code，PIC）。用户对 GCC 使用 -fpic 选项指示 GNU 编译系统生成 PIC 代码。共享库的编译必须总是使用该选项。在一个 x86-64 系统中，对同一个目标模块中符号的引用是不需要特殊处理使之成为 PIC。 Dec 24, 2016 · What GCC can do is actually generate either position-independent code (with -fPIC option), or "whatever" code (without -fPIC option). Function Pointers in position independent code (-fpic) on stm32 gcc I am trying to write a position independent firmware for an stm32 arm-cortex microcontroller compiled with gcc. Short example: struct process { struct process *next; const char *name; PT_THREAD((* thread)(struct pt *, process_event_t, process_data_t)); struct pt pt; unsigned char state, needspoll; }; process etimer_process Apr 8, 2015 · I have tried hard to figure out how to compile location independent code using GNU ARM toolchain but can not seem to make it work. Jul 29, 2015 · Что такое "position-independent code" (-fPIC in gcc) ? C++ Решение и ответ на вопрос 1506530 May 23, 2018 · CPU类型: X86-64 系统环境:CentOS Linux7 工具: GCC. 3编译器选项 Oct 22, 2022 · 文章浏览阅读5. There are other similar options of gcc for producing position-independent code. But it shall be used also as a firmware which is loaded over the radio channel. There is no operating system, so no dynamic linker is available. -fPIC # Access bss via the GOT. g. So far I have managed to successfully launch my application firmware from an offsetted location (with respect to the one provided by the linker) using a bootloader. c to position-independent code defaultly when link with shared library even this library don't use pic. get_pc_thunk. I'm actually using # a cross-compiler but we'll use regular gcc with x86 for the sake of the question gcc -Wl,-esome_function -o t. Code generated for the IBM RS/6000 is always position-independent. 6w次，点赞8次，收藏37次。ppc_85xx-gcc -shared -fPIC liberr. in struct. e. Nov 3, 2011 · This process involves copying the binary to a new location, jumping to it, and using it to flash the new bootloader in the original location. Feb 8, 2025 · This post addresses the specifics of compiling such a binary using the -fpie and -static-pie options in GCC to produce a self-contained, position-independent binary. There is no per-segment memory mapping: the entire executable is loaded as is, contiguously. Is it necessary to also build a. This is in contrast to position-dependent code, which is tied to a specific memory address and cannot be executed correctly if it is moved to a different location. Since they are dynamically loaded into the process runtime, it can't be known to which address their variables will be mapped to. so-fPIC 作用于编译阶段，告诉编译器产生与位置无关代码(Position-Independent Code)，则产生的代码中，没有绝对地址，全部使用相对地址，故而代码可以被加载器加载到内存的任意位置，都可以正确的执行。 Position Independent Code#. We have a c++ project, that might complicate things even more, I wouldn't know why, really, but I see some remarks on internet h Jul 10, 2015 · The accepted answer in the linked question is very simplistic, and only brings up one thing that differs between PIC and non-PIC code, generation of jumps that are relative instead of absolute. This section describes macros that help implement generation of position independent code. 3. However, the intel hex file format that I get out of objcopy always has address information on each line's header. I have a linker script similar to following: Nov 16, 2024 · 1、-fPIC（Position-Independent Code）功能：-fPIC 选项用于生成位置无关代码（Position-Independent Code）。位置无关代码可以在内存中的任意位置执行，而不需要在加载时进行重定位。 GNU Compiler Collection (GCC) Internals. , position-independent). elf -fPIC -nostdlib -T my_linker_script. As in my example in listing 6, such code can load the target address from the GOT itself and make the indirect call/jump. [ a ] PIC is commonly used for shared libraries , so that the same library code can be loaded at a location in each program's address space where it does not Dec 16, 2017 · So I do need position-independent code. Position-independent code requires special support, and therefore works only on certain machines. position independent code (PIC) with a global offset register I prefer PIC with global offset register, because it seems it's easier to implement and I'm not familiar with elf or any elf library. So far I have managed to successfully launch my application firmware from an offsetted Generate position-independent code (PIC) suitable for use in a shared library, if supported for the target machine. Dec 13, 2016 · Generate position-independent code (PIC) suitable for use in a shared library, if supported for the target machine. Basics of lazy binding Jan 16, 2022 · Position-independent code requires special support, and therefore works only on certain machines. It allows the machine code of certain operations to be located at any virtual address at runtime. However, to get an understanding of how position dependent code looked like, I compiled this int Add(int Jan 20, 2017 · I'm not sure if this is specific to the processor I'm using, so for what it's worth I'm using a Cortex M0+. To my surprise, he was more interested about “why” and not “how”. Feb 8, 2023 · Static libraries produce position dependent (machine) code by default. Do I need to pass this flag to linker also ? – 17. Nov 11, 2011 · Here is the R_X86_64_PC32 relocation the linker was complaining about. So it must be possible to generate code with absolute jumps. 在计算机领域中，地址无关代码 (position-independent code，PIC)，又称地址无关可执行文件 (position-independent executable，PIE) ，是指可在主存储器中任意位置正确地运行，而不受其绝对地址影响的一种机器码。PIC广泛使用于共享库，使得同一个库中的代码能够被加载到不同进程的地址空间中。PIC还用于缺少 The -pie option generates a dynamically linked position-independent executable. Generate position-independent code (PIC) suitable for use in a shared library, if supported for the target machine. For example, the -fpic option generates position-independent code like the -fpie option, but the generated code is suitable for use in a shared library instead of an executable. Code for shared libraries need to be compiled for another memory model, either PIC, or with -mcmodel=large which will compile without making that assumption. The Overflow Blog Our next phase—Q&A was just the beginning “Translation is the tip of the Position independent code needs to be made absolute as it’s loaded. Jan 16, 2022 · Recently I described my friend that I was working with Position-Independent Code on a Cortex-M0 and Cortex-M4 environment. Nov 14, 2013 · I'm creating a shared (. Instead, it uses relative addressing to access the variable, so the code can run at any memory address without modification. Apr 10, 2014 · The previous article explained how position independent code (PIC) works, with code compiled for the x86 architecture as an example. However, I'm struggling to understand why dynamic libraries need code independent of specific address. 如何做到地址无关的代码 Position-independent code does not need a PLT. Note: Clang uses the same option -fPIC and the purpose is same. gcc pie. Aug 7, 2023 · PIEとは. 代码段和数据段之间的偏移，在链接的时候由链接器给出，对于PIC来说非常重要。 May 23, 2014 · I have always thought that the generation of position independent code (PIC) basically only depended on the CPU one is compiling for. Some use cases: Copy code from slower FLASH to faster SRAM for execution. 4 20140725 My goal is to build an image that can be run from any properly-aligned offset in internal flash. Follow edited Oct 17 4 GCC编译不生成可执行文件; 5 如何正确使用 -fPIC 和 -fPIE GCC 选项; 23 gcc/clang编译器选项中的-f和-m代表什么意思？ 18 gcc如何找到as、ld和其他binutils可执行文件？ 27 微软Visual Studio中相当于GCC ld选项--whole-archive的是什么？ 6 什么是适用于位置无关可执行文件的正确 Mar 1, 2022 · Looks like a compiler or possibly linker bug. To do this, I've gathered that I need to compile as Position Independent Code (PIC). 地址无关代码，简称PIC，下文中都以PIC代替。 PIC一般用于动态库文件中，但并不是唯一，所以有时候也会用在可执行文件中。我想大家都知道静态库与动态库的区别，如果没有，我再稍微啰嗦一下: Dec 29, 2023 · set(POSITION_INDEPENDENT_CODE True) position-independent code (PIC) 编译动态库 . — Macro: FINALIZE_PIC By generating position-independent code, when two different programs (A and B) share a common library (libC. The relocation info is in special sections within the elf file. When you use "whatever" mode, the compiler simply ignores the matters of position-dependency and bases its decisions about code generation on other considerations. 2 release 1). Релокацию во время загрузки мы уже рассмотрели. DLL) library and I keep getting this message from the compiler (gcc): json. I tried just now with the sparc gcc with -fno-pic. so Howerve,gcc will compile main. So far I have tried building with -fpie option (using gcc) with not too much success. In computing, position-independent code [1] (PIC [1]) or position-independent executable (PIE) [2] is a body of machine code that executes properly regardless of its memory address. c . For this purpose the position independent code is needed. But I also have assembly code that needs to use PIC. My gtest library was not built for position-independent code :(Pics and pies. You can take a look at the source code of this blog post here: Jan 23, 2024 · 这四个编译选项与位置无关代码(Position Independent Code，PIC)和位置无关可执行文件(Position Independent Executable，PIE)有关。它们的作用主要是为了提高代码的可重定位性，使得代码更适用于共享库和在内存中的不同位置加载的情况。-fPIC(Position Independent Code) Aug 21, 2022 · As far as I know PIC is used primarily for shared libs, so there is no intent for GCC to compile an executable as PIE unless it was hinted to do it. Generally, the exec function will load the elf file and do the relocations. As a workaround code can be generated for the M4 instead. This all works fine with ARMCC (--ropi --rwpi). out main. My ideal scenario is for the code would be position-independent, but the data and bs Jun 14, 2021 · I'm very confused about position-independent code and its usage for dynamic libraries. However, after reading this in the GCC documentation : For the 386, GCC supports PIC for System V but not for the Sun 386i. Jul 20, 2024 · So, the code is position-independent because it does not use an absolute memory address to access the global variable global_var. It just can't link an object with such relocation into a shared library. If supported for the target machine, emit position-independent code, suitable for dynamic linking and avoiding any limit on the size of the global offset table. Jan 16, 2023 · Under Windows, this is done using a "base relocation table"; under Linux this is done using "position-independent code". The problem is I cannot find an example on how to achieve this. Their variables are mapped to hardcoded virtual memory addresses which is more efficient. Feb 27, 2019 · ppc_85xx-gcc -shared -fPIC liberr. Jun 5, 2021 · Position-Independent code (or PIC) is what is suitable for shared library code or if you want to use a loader to load and execute code anywhere in your address space. In this case, many modern OSs load an executable file to any (random) address in memory for security reasons (because it is harder to write a virus accessing the variable gprs if its address is not known). Back before we had MMUs and paging, all processes had to share physical address space, so it quickly made sense to make sure a program could be loaded at any 文章浏览阅读1. When this flag is set, the macros __pic__ and __PIC__ are defined to 1. The dynamic loader resolves the GOT entries when the program starts (the dynamic loader is not part of GCC; it is part of the operating system). 19 Position Independent Code ¶. Also PIE executables are not so useful because in every process' virtual address space there will be only one executable image that started it, and PIEs were made to be loaded several times at Nov 3, 2011 · This article explained what position independent code is, and how it helps create shared libraries with shareable read-only text sections. The address that the code veneer branches to isn't relocated properly because it doesn't show up in the list of relocations in the executable binary. All the documentation I've been able to find online talk about position-independent executables which are dynamically linked, and I wasn't able to find anything useful there. We will discuss how these features can be utilized in C programming for better memory management and efficient code execution. By default, static code is build assuming the whole program will stay in the lower 2G part of the memory address space. c -oliberr. There are some tradeoffs when choosing between PIC and its alternative (load-time relocation), and the eventual outcome really depends on a lot of factors, like the CPU architecture on which the program is Aug 15, 2021 · So how could the operating system tell which one should be treated as position independent code?? ADD 2 - 10:56 AM 8/16/2021. Basically it means that the code can run ‘anywhere’. Simply defining these macros is not enough to generate valid PIC; you must also add support to the hook TARGET_LEGITIMATE_ADDRESS_P and to the macro PRINT_OPERAND_ADDRESS, as well as LEGITIMIZE_ADDRESS. o is compiled with the position-independent code flag, because it becomes a shared library. I promised to cover PIC on x64 [1] in a separate article, so here we are. gcc; arm; stm32; position-independent-code; Share. I have tried using -fpic and -fpie options for the compiler and -pie for linker but when I use these options the compiler complains that no section is defined for either . ld -g -O0 my_code. 5k次，点赞5次，收藏11次。set(POSITION_INDEPENDENT_CODE True)position-independent code (PIC) 编译动态库 . c:1:0: warning: -fPIC ignored for target (all code is position independent) What does it mean th Oct 26, 2015 · I am using the GCC options -mpic-data-is-text-relative and -fpic to generate position independent code. I found this good example about -fPIC option of GCC: GCC -fPIC option and I figure out how it works. Aug 15, 2021 · gcc; nasm; ld; position-independent-code; or ask your own question. The Overflow Blog Shifting left without slowing down: Q&A with Moti Gindi of Apiiro “In the Nov 24, 2024 · -fPIC(Position Independent Code) 作用：生成位置无关的代码，适用于共享库。用途：当编译共享库时，通常需要使用-fPIC，以确保库中的代码可以在内存中的不同位置加载。-fPIE(Position Independent Executable) 作用：生成位置无关的可执行文件，适用于可执行文件。 Aug 6, 2005 · As for actual position independent code on x86: since there isn't EIP-relative data-addressing, some tricks are needed. so -fPIC作用于编译阶段，告诉编译器产生与位置无关代码(Position-Independent Code)，则产生的代码中，没有绝对地址，全部使用相对地址，故而代码可以被加载器加载到内存的任意位置，都可以正确的执行。 Oct 17, 2017 · I need a position independent code (PIC) working on STM32F401. rnhs vua bgcsb bmc pemn ahum rauo ukhrz ziauj nlmi kwuf iofm wlug tlmnpew qhggwf

Position independent code gcc. For Example a shellcode is PIC.