In `llvm-cov show`, this option rounds counters (line, branch) to
`[1,0]` at rendering. This will be useful when the number of counts
doesn't interest but **Covered/uncoverd** does.

NFC except for calculating `Total`. I've replaced
`(uint64_t)+(uint64_t)` with `(double)+(double)`.

This is still inexact with large numbers `(1LL << 53)` but will be expected to prevent possible overflow.

Currently both True/False counts were folded. It lost the information,
"It is True or False before folding." It prevented recalling branch
counts in merging template instantiations.

In `llvm-cov`, a folded branch is shown as:

- `[True: n, Folded]`
- `[Folded, False n]`

In the case If `n` is zero, a branch is reported as "uncovered". This is
distinguished from "folded" branch. When folded branches are merged,
`Folded` may be dissolved.

In the coverage map, either `Counter` is `Zero`. Currently both were
`Zero`.

Since "partial fold" has been introduced, either case in `switch` is
omitted as `Folded`.

Each `case:` in `switch` is reported as `[True: n, Folded]`, since
`False` count doesn't show meaningful value.

When `switch` doesn't have `default:`, `switch (Cond)` is reported as
`[Folded, False: n]`, since `True` count was just the sum of `case`(s).
`switch` with `default` can be considered as "the statement that doesn't
have any `False`(s)".

I replaced "jump to first uncovered line" with UI buttons and keyboard
shortcut to jump between uncovered parts of code: lines (key L), branchs
(key B), regions (key R).

User can also jump in reverse direction with shift+key.

1. add the missing condition for MC/DC in hasSubViews()
2. add style for selected line
3. remove name="Ln" attribute in the link within MC/DC views
4. remove color for \n

Part 2 of 3. This includes the Visualization and Evaluation components.

Differential Revision: https://reviews.llvm.org/D138847

This reverts commit 618a22144db5e45da8c95dc22064103e1b5e5b71.

Buildbots failing on windows and one other issue.

Part 2 of 3. This includes the Visualization and Evaluation components.

Differential Revision: https://reviews.llvm.org/D138847

This is a GSoC 2023 project ([discourse link](https://discourse.llvm.org/t/coverage-support-a-hierarchical-directory-structure-in-generated-coverage-html-reports/68239)).

llvm-cov currently generates a single top-level index HTML file, which causes rendering scalability issues in large projects. This patch adds support for hierarchical directory structure into the HTML reports to solve scalability issues by introducing the following changes:

- Added a new command line option `--show-directory-coverage` for `llvm-cov show`. It works both for `--format=html` and `--format=text`.
- Two new classes: `CoveragePrinterHTMLDirectory` and `CoveragePrinterTextDirectory` was added to support the new option.
- A tool class `DirectoryCoverageReport` was added to support the two classes above.
- Updated the document.
- Added a new regression test for `--show-directory-coverage`.

Reviewed By: phosek, gulfem

Differential Revision: https://reviews.llvm.org/D151283