What is the -fPIE option for position-independent executables in gcc and ld?

by

PIE is to support address space layout randomization (ASLR) in executable files.

Before the PIE mode was created, the program’s executable could not be placed at a random address in memory, only position independent code (PIC) dynamic libraries could be relocated to a random offset. It works very much like what PIC does for dynamic libraries, the difference is that a Procedure Linkage Table (PLT) is not created, instead PC-relative relocation is used.

After enabling PIE support in gcc/linkers, the body of program is compiled and linked as position-independent code. A dynamic linker does full relocation processing on the program module, just like dynamic libraries. Any usage of global data is converted to access via the Global Offsets Table (GOT) and GOT relocations are added.

PIE is well described in this OpenBSD PIE presentation.

Changes to functions are shown in this slide (PIE vs PIC).

x86 pic vs pie

Local global variables and functions are optimized in pie

External global variables and functions are same as pic

and in this slide (PIE vs old-style linking)

x86 pie vs no-flags (fixed)

Local global variables and functions are similar to fixed

External global variables and functions are same as pic

Note, that PIE may be incompatible with -static

More Related Contents:

  1. Why does the order in which libraries are linked sometimes cause errors in GCC?
  2. Telling gcc directly to link a library statically
  3. libpthread.so.0: error adding symbols: DSO missing from command line
  4. What are the –start-group and –end-group command line options?
  5. Use both static and dynamically linked libraries in gcc
  6. combine two GCC compiled .o object files into a third .o file
  7. GNU gcc/ld – wrapping a call to symbol with caller and callee defined in the same object file
  8. static linking only some libraries
  9. How to specify non-default shared-library path in GCC Linux? Getting “error while loading shared libraries” when running
  10. CMake and Static Linking
  11. correct usage of rpath (relative vs absolute)
  12. Compile with older libc (version `GLIBC_2.14′ not found)
  13. Change stack size for a C++ application in Linux during compilation with GNU compiler
  14. The advantages of using 32bit registers/instructions in x86-64
  15. How to suppress GCC warnings from library headers?
  16. How do I force make/GCC to show me the commands?
  17. Vectorizing with unaligned buffers: using VMASKMOVPS: generating a mask from a misalignment count? Or not using that insn at all
  18. ld cannot find an existing library
  19. How to specify new GCC path for CMake
  20. How do I check if gcc is performing tail-recursion optimization?
  21. How to cross compile from Mac OS X to Linux x86?
  22. Compile Python code to statically linked executable with Cython
  23. how to install gcc on windows 7 machine?
  24. How to use OpenSSL with GCC?
  25. How to make gcc warn about passing wrong enum to a function
  26. How to detect SSE/SSE2/AVX/AVX2/AVX-512/AVX-128-FMA/KCVI availability at compile-time?
  27. -isystem on a system include directory causes errors
  28. Does a compiler always produce an assembly code?
  29. Why gcc 4.1 + gcov reports 100% branch coverage and newer (4.4, 4.6, 4.8) reports 50% for “p = new class;” line?
  30. undefined reference to symbol even when nm indicates that this symbol is present in the shared library

Leave a Comment