Changes

Revert "[clang][Fuchsia] Add relative-vtables multilib"

This reverts commit fdbd84c6c819d4462546961f6086c1524d5d5ae8.

Reverting due to failing CI builders for Fuchsia's toolchain:
https://luci-milo.appspot.com/p/fuchsia/builders/ci/clang-linux-x64/b8862150211240186992?

Add help text for -nogpuinc

Differential Revision: https://reviews.llvm.org/D92339

[lldb] Refactor GetDeviceSupportDirectoryNames and GetPlatformName (NFC)

Both functions are effectively returning a single string literal. Change
the interface to return a llvm::StringRef instead of populating a vector
of std::strings or returning a std::string respectively.

Add MachineModuleInfo constructor with external MCContext

Adds a constructor to MachineModuleInfo and MachineModuleInfoWapperPass that
takes an external MCContext. If provided, the external context will be used
throughout codegen instead of MMI's default one.

This enables external drivers to take ownership of data put on the MMI's context
during codegen. The internal context is used otherwise and destroyed upon
finish.

Differential Revision: https://reviews.llvm.org/D91313

[RISCV] Rename RISCVGenSystemOperands.inc to RISCVGenSearchableTables.inc to prepare for more tables. NFC

D89449 adds more tables so renaming as a pre-commit for that.

Initial commit of mktime.

This introduces mktime to LLVM libc, based on C99/C2X/Single Unix Spec.

Co-authored-by: Jeff Bailey <jeffbailey@google.com>

This change doesn't handle TIMEZONE,  tm_isdst and leap seconds.  It returns -1 for invalid dates. I have verified the return results for all the possible dates with glibc's mktime.

TODO:
+ Handle leap seconds.
+ Handle out of range time and date values that don't overflow or underflow.
+ Implement the following suggestion Siva - As we start accumulating the seconds, we should be able to check if the next amount of seconds to be added can lead to an overflow. If it does, return the overflow value.  If not keep accumulating. The benefit is that, we don't have to validate every input, and also do not need the special cases for sizeof(time_t) == 4.
+ Handle timezone and update of tm_isdst

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D91551

[DSE] Remove a redundant call to getLocForWriteEx()

Differential Revision: https://reviews.llvm.org/D92263

[Remarks][1/2] Expand remarks hotness threshold option support in more tools

This is the #1 of 2 changes that make remarks hotness threshold option
available in more tools. The changes also allow the threshold to sync with
hotness threshold from profile summary with special value 'auto'.

This change modifies the interface of lto::setupLLVMOptimizationRemarks() to
accept remarks hotness threshold. Update all the tools that use it with remarks
hotness threshold options:

* lld: '--opt-remarks-hotness-threshold='
* llvm-lto2: '--pass-remarks-hotness-threshold='
* llvm-lto: '--lto-pass-remarks-hotness-threshold='
* gold plugin: '-plugin-opt=opt-remarks-hotness-threshold='

Differential Revision: https://reviews.llvm.org/D85809

[Remarks][2/2] Expand remarks hotness threshold option support in more tools

This is the #2 of 2 changes that make remarks hotness threshold option
available in more tools. The changes also allow the threshold to sync with
hotness threshold from profile summary with special value 'auto'.

This change expands remarks hotness threshold option
-fdiagnostics-hotness-threshold in clang and *-remarks-hotness-threshold in
other tools to utilize hotness threshold from profile summary.

Remarks hotness filtering relies on several driver options. Table below lists
how different options are correlated and affect final remarks outputs:

| profile | hotness | threshold | remarks printed |
|---------|---------|-----------|-----------------|
| No      | No      | No        | All             |
| No      | No      | Yes       | None            |
| No      | Yes     | No        | All             |
| No      | Yes     | Yes       | None            |
| Yes     | No      | No        | All             |
| Yes     | No      | Yes       | None            |
| Yes     | Yes     | No        | All             |
| Yes     | Yes     | Yes       | >=threshold     |

In the presence of profile summary, it is often more desirable to directly use
the hotness threshold from profile summary. The new argument value 'auto'
indicates threshold will be synced with hotness threshold from profile summary
during compilation. The "auto" threshold relies on the availability of profile
summary. In case of missing such information, no remarks will be generated.

Differential Revision: https://reviews.llvm.org/D85808

[CodeView] Remove unused declaration collectInlineSiteChildren (NFC)

The function definition was removed on Sep 7, 2016 in commit
a9f4cc9510546f5728258524d344a3e03e43500b.  The declaration seems to be
unused since then.