When doing firmware/kernel debugging, it is frequent that binaries and
debug info need to be retrieved / downloaded, and the lack of progress
reports made for a poor experience, with lldb seemingly hung while
downloading things over the network. This PR adds progress reports to
the critical sites for these use cases.

C++20 will automatically generate an operator== with reversed operand
order, which is ambiguous with the written operator== when one argument
is marked const and the other isn't.

These operators currently trigger -Wambiguous-reversed-operator at usage
sites lldb/source/Symbol/SymbolFileOnDemand.cpp:68 and
lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp:1286.

There is no reason why this function should be returning a ConstString.

While modifying these files, I also fixed several instances where
GetPluginName and GetPluginNameStatic were returning different strings.

I am not changing the return type of GetPluginNameStatic in this patch, as that
would necessitate additional changes, and this patch is big enough as it is.

Differential Revision: https://reviews.llvm.org/D111877

In all these years, we haven't found a use for this function (it has
zero callers). Lets just remove the boilerplate.

Differential Revision: https://reviews.llvm.org/D109600

Replace default bodies of special member functions with = default;

$ run-clang-tidy.py -header-filter='lldb' -checks='-*,modernize-use-equals-default' -fix ,

https://clang.llvm.org/extra/clang-tidy/checks/modernize-use-equals-default.html

Differential revision: https://reviews.llvm.org/D104041

This converts a default constructor's member initializers into C++11
default member initializers. This patch was automatically generated with
clang-tidy and the modernize-use-default-member-init check.

$ run-clang-tidy.py -header-filter='lldb' -checks='-*,modernize-use-default-member-init' -fix

This is a mass-refactoring patch and this commit will be added to
.git-blame-ignore-revs.

Differential revision: https://reviews.llvm.org/D103483

Summary:
This is how I applied my clang-tidy check (see
https://reviews.llvm.org/D80531) in order to remove
`DISALLOW_COPY_AND_ASSIGN` and have deleted copy ctors and deleted
assignment operators instead.

```
lang=bash
grep DISALLOW_COPY_AND_ASSIGN /opt/notnfs/kkleine/llvm/lldb -r -l | sort | uniq > files

for i in $(cat files);
do
  clang-tidy \
    --checks="-*,modernize-replace-disallow-copy-and-assign-macro" \
    --format-style=LLVM \
    --header-filter=.* \
    --fix \
    -fix-errors \
    $i;
done
```

Reviewers: espindola, labath, aprantl, teemperor

Reviewed By: labath, aprantl, teemperor

Subscribers: teemperor, aprantl, labath, emaste, sbc100, aheejin, MaskRay, arphaman, usaxena95, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D80543

LLDB has a few different styles of header guards and they're not very
consistent because things get moved around or copy/pasted. This patch
unifies the header guards across LLDB and converts everything to match
LLVM's style.

Differential revision: https://reviews.llvm.org/D74743

llvm-svn: 364614