mirror of https://github.com/acidanthera/audk.git
d2687f23c9
We take great care to avoid GOT based relocations in EDK2 executables, primarily because they are pointless - we don't care about things like the CoW footprint or relocations that target read-only sections, and so GOT entries only bloat the binary. However, in some cases (e.g., when building the relocatable PrePi SEC module in ArmVirtPkg with the CLANG38 toolchain), we may end up with some GOT based relocations nonetheless, which break the build since GenFw does not know how to deal with them. The relocations emitted in this case are ADRP/LDR instruction pairs that are annotated as GOT based, which means that it is the linker's job to emit the GOT entry and tag it with an appropriate dynamic relocation that ensures that the correct absolute value is stored into the GOT entry when the executable is loaded. This dynamic relocation is not visible to GenFw, and so populating the PE/COFF relocation section for these entries is non-trivial. Since each ADRP/LDR pair refers to a single symbol that is local to the binary (given that shared libraries are not supported), we can actually convert the ADRP/LDR pair into an ADRP/ADD pair that produces the symbol address directly rather than loading it from memory. This leaves the GOT entry in the binary, but since it is now unused, it is no longer necessary to emit a PE/COFF relocation entry for it. Acked-by: Liming Gao <liming.gao@intel.com> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> |
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| Bin | ||
| BinWrappers | ||
| Conf | ||
| Scripts | ||
| Source | ||
| Tests | ||
| UserManuals | ||
| .gitignore | ||
| BuildEnv | ||
| GNUmakefile | ||
| Makefile | ||
| ReadMe.txt | ||
| get_vsvars.bat | ||
| set_vsprefix_envs.bat | ||
| toolsetup.bat | ||
ReadMe.txt
This directory contains the next generation of EDK II build tools and template files. Templates are located in the Conf directory, while the tools executables for Microsoft Windows 32-bit Operating Systems are located in the Bin\Win32 directory, other directory contains tools source. 1. Build step to generate the binary tools. === Windows/Visual Studio Notes === To build the BaseTools, you should run the standard vsvars32.bat script from your preferred Visual Studio installation or you can run get_vsvars.bat to use latest automatically detected version. In addition to this, you should set the following environment variables: * EDK_TOOLS_PATH - Path to the BaseTools sub directory under the edk2 tree * BASE_TOOLS_PATH - The directory where the BaseTools source is located. (It is the same directory where this README.txt is located.) After this, you can run the toolsetup.bat file, which is in the same directory as this file. It should setup the remainder of the environment, and build the tools if necessary. Please also refer to the 'BuildNotes.txt' file for more information on building under Windows. === Unix-like operating systems === To build on Unix-like operating systems, you only need to type 'make' in the base directory of the project. === Ubuntu Notes === On Ubuntu, the following command should install all the necessary build packages to build all the C BaseTools: sudo apt-get install build-essential uuid-dev === Python sqlite3 module === On Windows, the cx_freeze will not copy the sqlite3.dll to the frozen binary directory (the same directory as build.exe and GenFds.exe). Please copy it manually from <PythonHome>\DLLs. The Python distributed with most recent Linux will have sqlite3 module built in. If not, please install sqlit3 package separately. 26-OCT-2011