4e958b4d7c
The main motivation for this change is to avoid ambiguity because mapping symbol names may not be unique across a binary and do not allow uniquely identifying target address. So that mapping symbols used as branch target labels make llvm-objdump output less readable. Another point is that mapping symbols sometimes appear in non-allocatable sections, like debug info sections which make objdump output even more confusing. For example, a small AArch64 executable may contain plenty of `$d[.*]` symbols and none of them would be useful as a label for resolving a branch or a memory operand target address: ``` 0000000000000254 l .note.ABI-tag 0000000000000000 $d 00000000000008d4 l .eh_frame 0000000000000000 $d 0000000000000868 l .rodata 0000000000000000 $d 0000000000011028 l .data 0000000000000000 $d 0000000000010db8 l .fini_array 0000000000000000 $d 0000000000010db0 l .init_array 0000000000000000 $d 00000000000008e8 l .eh_frame 0000000000000000 $d 0000000000011034 l .bss 0000000000000000 $d ``` Note that GNU objdump doesn't use mapping symbols as branch target labels for all targets that support such symbols (ARM, AArch64, CSKY). Differential Revision: https://reviews.llvm.org/D139131
The LLVM Compiler Infrastructure ================================ This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments. LLVM is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt. Please see the documentation provided in docs/ for further assistance with LLVM, and in particular docs/GettingStarted.rst for getting started with LLVM and docs/README.txt for an overview of LLVM's documentation setup. If you are writing a package for LLVM, see docs/Packaging.rst for our suggestions.