[llvm-cov gcov] Fix calculating coverage of template functions

Template functions share the same lines in source files, so the common
container of lines' properties cannot be used to calculate the c

[llvm-cov gcov] Fix calculating coverage of template functions

Template functions share the same lines in source files, so the common
container of lines' properties cannot be used to calculate the coverage
statistics of individual functions.

> cat tmpl.cpp
template <int N> int test() { return N; }
int main() { return test<1>() + test<2>(); }
> clang++ --coverage tmpl.cpp -o tmpl
> ./tmpl
> llvm-cov gcov tmpl.cpp -f
...
Function '_Z4testILi1EEiv'
Lines executed:100.00% of 1

Function '_Z4testILi2EEiv'
Lines executed:-nan% of 0
...
> llvm-cov-patched gcov tmpl.cpp -f
...
Function '_Z4testILi1EEiv'
Lines executed:100.00% of 1

Function '_Z4testILi2EEiv'
Lines executed:100.00% of 1
...

Differential Revision: https://reviews.llvm.org/D121390

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Cleanup includes: ProfileData

Estimation of the impact on preprocessor output:

before: 1067349756
after: 1065940348

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-clea

Cleanup includes: ProfileData

Estimation of the impact on preprocessor output:

before: 1067349756
after: 1065940348

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D120434

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[llvm] Use true/false instead of 1/0 (NFC)

Identified with modernize-use-bool-literals.

[llvm-cov gcov] Support GCC 12 format

GCC 12 will change the length field to represent the number of bytes instead of
32-bit words. This avoids padding for strings.

[llvm-cov gcov] Change case to match the prevailing style && replace getString with readString

[SystemZ][z/OS][Windows] Add new OF_TextWithCRLF flag and use this flag instead of OF_Text

Problem:
On SystemZ we need to open text files in text mode. On Windows, files opened in text mode adds a C

[SystemZ][z/OS][Windows] Add new OF_TextWithCRLF flag and use this flag instead of OF_Text

Problem:
On SystemZ we need to open text files in text mode. On Windows, files opened in text mode adds a CRLF '\r\n' which may not be desirable.

Solution:
This patch adds two new flags

- OF_CRLF which indicates that CRLF translation is used.
- OF_TextWithCRLF = OF_Text | OF_CRLF indicates that the file is text and uses CRLF translation.

Developers should now use either the OF_Text or OF_TextWithCRLF for text files and OF_None for binary files. If the developer doesn't want carriage returns on Windows, they should use OF_Text, if they do want carriage returns on Windows, they should use OF_TextWithCRLF.

So this is the behaviour per platform with my patch:

z/OS:
OF_None: open in binary mode
OF_Text : open in text mode
OF_TextWithCRLF: open in text mode

Windows:
OF_None: open file with no carriage return
OF_Text: open file with no carriage return
OF_TextWithCRLF: open file with carriage return

The Major change is in llvm/lib/Support/Windows/Path.inc to only set text mode if the OF_CRLF is set.
```
if (Flags & OF_CRLF)
CrtOpenFlags |= _O_TEXT;
```

These following files are the ones that still use OF_Text which I left unchanged. I modified all these except raw_ostream.cpp in recent patches so I know these were previously in Binary mode on Windows.
./llvm/lib/Support/raw_ostream.cpp
./llvm/lib/TableGen/Main.cpp
./llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
./llvm/unittests/Support/Path.cpp
./clang/lib/StaticAnalyzer/Core/HTMLDiagnostics.cpp
./clang/lib/Frontend/CompilerInstance.cpp
./clang/lib/Driver/Driver.cpp
./clang/lib/Driver/ToolChains/Clang.cpp

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D99426

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[NFC] Reordering parameters in getFile and getFileOrSTDIN

In future patches I will be setting the IsText parameter frequently so I will refactor the args to be in the following order. I have removed

[NFC] Reordering parameters in getFile and getFileOrSTDIN

In future patches I will be setting the IsText parameter frequently so I will refactor the args to be in the following order. I have removed the FileSize parameter because it is never used.

```
static ErrorOr<std::unique_ptr<MemoryBuffer>>
getFile(const Twine &Filename, bool IsText = false,
bool RequiresNullTerminator = true, bool IsVolatile = false);

static ErrorOr<std::unique_ptr<MemoryBuffer>>
getFileOrSTDIN(const Twine &Filename, bool IsText = false,
bool RequiresNullTerminator = true);

static ErrorOr<std::unique_ptr<MB>>
getFileAux(const Twine &Filename, uint64_t MapSize, uint64_t Offset,
bool IsText, bool RequiresNullTerminator, bool IsVolatile);

static ErrorOr<std::unique_ptr<WritableMemoryBuffer>>
getFile(const Twine &Filename, bool IsVolatile = false);
```

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D99182

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[ProfileData] GCOVFile::readGCNO - silence undefined pointer warning. NFCI.

Silence clang static analyzer warning that 'fn' could still be in an undefined state - this shouldn't happen depending on

[ProfileData] GCOVFile::readGCNO - silence undefined pointer warning. NFCI.

Silence clang static analyzer warning that 'fn' could still be in an undefined state - this shouldn't happen depending on the likely tag order, but the analyzer can't know that.

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[llvm-cov gcov] Replace Donald B. Johnson's cycle enumeration with iterative cycle finding

gcov computes the line execution count as the sum of (a) counts from
predecessors on other lines and (b) th

[llvm-cov gcov] Replace Donald B. Johnson's cycle enumeration with iterative cycle finding

gcov computes the line execution count as the sum of (a) counts from
predecessors on other lines and (b) the sum of loop execution counts of blocks
on the same line (think of loops on one line).

For (b), we use Donald B. Johnson's cycle enumeration algorithm and perform
cycle cancelling for each cycle. This number of candidate cycles were
exponential and D93036 made it polynomial by skipping zero count cycles. The
time complexity is high (O(V*E^2) (it could be O(E^2) but the linear `Blocks`
check made it higher) and the implementation is complex.

We could just identify loops and sum all back edges. However, this requires a
dominator tree construction which is more complex. The time complexity can be
decreased to almost linear, though.

This patch just performs cycle cancelling iteratively. Add two members
`traversable` and `incoming` to GCOVArc. There are 3 states:

* `!traversable`: blocks not on this line or explored blocks
* `traversable && incoming == nullptr`: unexplored blocks
* `traversable && incoming != nullptr`: blocks which are being explored (on the stack)

If an arc points to a block being explored, a cycle has been found.

Let E be the number of arcs. Every time a cycle is found, at least one arc is
saturated (`edgeCount` reduced to 0), so there are at most E cycles. Finding one
cycle takes O(E) time, so the overall time complexity is O(E^2). Note that we
always augment through a back edge and never need to augment its reverse edge so
reverse edges in traditional flow networks are not needed.

Reviewed By: xinhaoyuan

Differential Revision: https://reviews.llvm.org/D93073

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[llvm-cov][gcov] Optimize the cycle counting algorithm by skipping zero count cycles

This change is similar to http://gcc.gnu.org/PR90380

This reduces the complexity from exponential to polynomial

[llvm-cov][gcov] Optimize the cycle counting algorithm by skipping zero count cycles

This change is similar to http://gcc.gnu.org/PR90380

This reduces the complexity from exponential to polynomial of the arcs.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D93036

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Fix various format specifier mismatches

Format specifiers of incorrect length are replaced with format specifier
macros from `<cinttypes>` matching the typedefs used to declare the type
of the value

Fix various format specifier mismatches

Format specifiers of incorrect length are replaced with format specifier
macros from `<cinttypes>` matching the typedefs used to declare the type
of the value being printed.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D89637

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[llvm-cov gcov] Add --demangled-names (-m)

gcov 4.9 introduced the option.

[llvm-cov gcov] Refactor counting and reporting

The current organization of FileInfo and its referenced utility functions of
(GCOVFile, GCOVFunction, GCOVBlock) is messy. Some members of FileInfo ar

[llvm-cov gcov] Refactor counting and reporting

The current organization of FileInfo and its referenced utility functions of
(GCOVFile, GCOVFunction, GCOVBlock) is messy. Some members of FileInfo are just
copied from GCOVFile. FileInfo::print (.gcov output and --intermediate output)
is interleaved with branch statistics and computation of line execution counts.
--intermediate has to do redundant .gcov output to gather branch statistics.

This patch deletes lots of code and introduces a clearer work flow:

```
fn collectFunction
for each block b
for each line lineNum
let line be LineInfo of the file on lineNum
line.exists = 1
increment function's lines & linesExec if necessary
increment line.count
line.blocks.push_back(&b)

fn collectSourceLine
compute cycle counts
count = incoming_counts + cycle_counts
if line.exists
++summary->lines
if line.count
++summary->linesExec

fn collectSource
for each line
call collectSourceLine

fn main
for each function
call collectFunction
print function summary
for each source file
call collectSource
print file summary
annotate the source file with line execution counts
if -i
print intermediate file
```

The output order of functions and files now follows the original order in
.gcno files.

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[llvm-cov gcov] Add -r (--relative-only) && -s (--source-prefix)

gcov 4.7 introduced the two options.
https://sourceware.org/pipermail/gcc-patches/2011-November/328782.html

-r only dumps files with

[llvm-cov gcov] Add -r (--relative-only) && -s (--source-prefix)

gcov 4.7 introduced the two options.
https://sourceware.org/pipermail/gcc-patches/2011-November/328782.html

-r only dumps files with relative paths or absolute paths with the prefix
specified by -s. The two options are useful filtering out system header files.

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[llvm-cov gcov] Improve accuracy when some edges are not measured

Also guard against infinite recursion if GCOV_ARC_ON_TREE edges contain a cycle.

[llvm-cov gcov] Simply computation of line counts and exit block counter

[llvm-cov gcov] Compute unmeasured arc counts by Kirchhoff's circuit law

For a CFG G=(V,E), Knuth describes that by Kirchoff's circuit law, the minimum
number of counters necessary is |E|-(|V|-1). T

[llvm-cov gcov] Compute unmeasured arc counts by Kirchhoff's circuit law

For a CFG G=(V,E), Knuth describes that by Kirchoff's circuit law, the minimum
number of counters necessary is |E|-(|V|-1). The emitted edges form a spanning
tree. libgcov emitted .gcda files leverages this optimization while clang
--coverage's doesn't.

Propagate counts by Kirchhoff's circuit law so that llvm-cov gcov can
correctly print line counts of gcc --coverage emitted files and enable
the future improvement of clang --coverage.

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[llvm-cov gcov] Don't require NUL terminator when reading files

.gcno, .gcda and source files can be modified while we are reading them. If the
concurrent modification of a file being read nullifies

[llvm-cov gcov] Don't require NUL terminator when reading files

.gcno, .gcda and source files can be modified while we are reading them. If the
concurrent modification of a file being read nullifies the NUL terminator
assumption, llvm-cov can trip over an assertion failure in MemoryBuffer::init.
This is not so rare - the source files can be in an editor and .gcda can be
written by an running process (if the process forks, when .gcda gets written is
probably more unpredictable).

There is no accompanying test because an assertion failure requires data
races with some involved setting.

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[llvm-cov gcov] Support clang<11 fake 4.2 format

Test cases are restored from a3bed4bd3743b5fee1e66116a63089df742bcae1

[llvm-cov gcov] Don't suppress .gcov output if .gcda is corrupted

If .gcda is corrupted, gcov continues to produce a .gcov and just
assumes execution counts are zeros. This is reasonable, because th

[llvm-cov gcov] Don't suppress .gcov output if .gcda is corrupted

If .gcda is corrupted, gcov continues to produce a .gcov and just
assumes execution counts are zeros. This is reasonable, because the
program can corrupt its .gcda output. The code path should be similar to
the code path without .gcda.

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[gcov] Add -i --intermediate-format

Between gcov 4.9~8, `gcov -i $file` prints coverage information to
$file.gcov in an intermediate text format (single file, instead of
$source.gcov for each source

[gcov] Add -i --intermediate-format

Between gcov 4.9~8, `gcov -i $file` prints coverage information to
$file.gcov in an intermediate text format (single file, instead of
$source.gcov for each source file).

lcov newer than 2019-05-24 detects -i support and uses it to increase
processing speed. gcov 9 (GCC r265587) removed --intermediate-format
and -i was changed to mean --json-format. However, we consider this
format still useful and support it. geninfo (part of lcov) supports this
format even if we announce that we are compatible with gcov 9.0.0

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[gcov] Refactor llvm-cov gcov and add SourceInfo

[gcov] Improve tests and lower the minimum supported version to gcov 3.4

global-ctor.ll no longer checks what it intended to check
(@_GLOBAL__sub_I_global-ctor.ll needs a !dbg to work).
Rewrite it.

[gcov] Improve tests and lower the minimum supported version to gcov 3.4

global-ctor.ll no longer checks what it intended to check
(@_GLOBAL__sub_I_global-ctor.ll needs a !dbg to work).
Rewrite it.

gcov 3.4 and gcov 4.2 use the same format, thus we can lower the version
requirement to 3.4

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[gcov] Don't error 'unexpected end of memory buffe'

[gcov] Make `Creating 'filename'` compatible with gcov

And clean up llvm-cov.test a bit