MFC r276666:

Eliminate uninitialized variable warnings in kernel and module builds when
building with gcc 4.2

MFC r268774:

After r261991, clang warnings about unused functions in the kernel were
completely silenced. Make sure these warnings appear again, so there is
some incentive to fix them, but do not error out the whole kernel build
for them.

Noticed by: steven@pyro.eu.org
PR: 191867

MFC r263749,267146:

>r267146 | imp | 2014-06-05 22:08:55 -0600 (Thu, 05 Jun 2014) | 4 lines
>Restore comments accidentally removed.

>r263749 | imp | 2014-03-25 16:08:31 -0600 (Tue, 25 Mar 2014) | 18 lines
>Rather than require a makeoptions DEBUG to get debug correct,
>add it in kern.mk, but only if we're using clang. While this
>option is supported by both clang and gcc, in the future there
>may be changes to clang which change the defaults that require
>a tweak to build our kernel such that other tools in our tree
>will work. Set a good example by forcing -gdwarf-2 only for
>clang builds, and only if the user hasn't specified another
>dwarf level already. Update UPDATING to reflect the changed
>state of affairs. This also keeps us from having to update
>all the ARM kernels to add this, and also keeps us from
>in the future having to update all the MIPS kernels and is
>one less place the user will have to know to do something
>special for clang and one less thing developers will need
>to do when moving an architecture to clang.

MFC r262613:

Merge the projects/clang-sparc64 branch back to head. This brings in
several updates from the llvm and clang trunks to make the sparc64
backend fully functional.

Apart from one patch to sys/sparc64/include/pcpu.h which is still under
discussion, this makes it possible to let clang fully build world and
kernel for sparc64.

Any assistance with testing this on actual sparc64 hardware is greatly
appreciated, as there will unavoidably be bugs left.

Many thanks go to Roman Divacky for his upstream work on getting the
sparc64 backend into shape.

MFC r262985:

Repair a few minor mismerges from r262261 in the clang-sparc64 project
branch. This is also to minimize differences with upstream.

MFC 261991:

Upgrade our copy of llvm/clang to 3.4 release. This version supports
all of the features in the current working draft of the upcoming C++
standard, provisionally named C++1y.

The code generator's performance is greatly increased, and the loop
auto-vectorizer is now enabled at -Os and -O2 in addition to -O3. The
PowerPC backend has made several major improvements to code generation
quality and compile time, and the X86, SPARC, ARM32, Aarch64 and SystemZ
backends have all seen major feature work.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.4/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.4/tools/clang/docs/ReleaseNotes.html>

MFC 262121 (by emaste):

Update lldb for clang/llvm 3.4 import

This commit largely restores the lldb source to the upstream r196259
snapshot with the addition of threaded inferior support and a few bug
fixes.

Specific upstream lldb revisions restored include:
SVN git
181387 779e6ac
181703 7bef4e2
182099 b31044e
182650 f2dcf35
182683 0d91b80
183862 15c1774
183929 99447a6
184177 0b2934b
184948 4dc3761
184954 007e7bc
186990 eebd175

Sponsored by: DARPA, AFRL

MFC 262186 (by emaste):

Fix mismerge in r262121

A break statement was lost in the merge. The error had no functional
impact, but restore it to reduce the diff against upstream.

MFC 262303:

Pull in r197521 from upstream clang trunk (by rdivacky):

Use the integrated assembler by default on FreeBSD/ppc and ppc64.

Requested by: jhibbits

MFC 262611:

Pull in r196874 from upstream llvm trunk:

Fix a crash that occurs when PWD is invalid.

MCJIT needs to be able to run in hostile environments, even when PWD
is invalid. There's no need to crash MCJIT in this case.

The obvious fix is to simply leave MCContext's CompilationDir empty
when PWD can't be determined. This way, MCJIT clients,
and other clients that link with LLVM don't need a valid working directory.

If we do want to guarantee valid CompilationDir, that should be done
only for clients of getCompilationDir(). This is as simple as checking
for an empty string.

The only current use of getCompilationDir is EmitGenDwarfInfo, which
won't conceivably run with an invalid working dir. However, in the
purely hypothetically and untestable case that this happens, the
AT_comp_dir will be omitted from the compilation_unit DIE.

This should help fix assertions occurring with ports-mgmt/tinderbox,
when it is using jails, and sometimes invalidates clang's current
working directory.

Reported by: decke

MFC 262809:

Pull in r203007 from upstream clang trunk:

Don't produce an alias between destructors with different calling conventions.

Fixes pr19007.

(Please note that is an LLVM PR identifier, not a FreeBSD one.)

This should fix Firefox and/or libxul crashes (due to problems with
regparm/stdcall calling conventions) on i386.

Reported by: multiple users on freebsd-current
PR: bin/187103

MFC 263048:

Repair recognition of "CC" as an alias for the C++ compiler, since it
was silently broken by upstream for a Windows-specific use-case.

Apparently some versions of CMake still rely on this archaic feature...

Reported by: rakuco

MFC 263049:

Garbage collect the old way of adding the libstdc++ include directories
in clang's InitHeaderSearch.cpp. This has been superseded by David
Chisnall's commit in r255321.

Moreover, if libc++ is used, the libstdc++ include directories should
not be in the search path at all. These directories are now only used
if you pass -stdlib=libstdc++.

MFC r276666:

Eliminate uninitialized variable warnings in kernel and module builds when
building with gcc 4.2

MFC r268774:

After r261991, clang warnings about unused functions in the kernel were
completely silenced. Make sure these warnings appear again, so there is
some incentive to fix them, but do not error out the whole kernel build
for them.

Noticed by: steven@pyro.eu.org
PR: 191867

MFC r263749,267146:

>r267146 | imp | 2014-06-05 22:08:55 -0600 (Thu, 05 Jun 2014) | 4 lines
>Restore comments accidentally removed.

>r263749 | imp | 2014-03-25 16:08:31 -0600 (Tue, 25 Mar 2014) | 18 lines
>Rather than require a makeoptions DEBUG to get debug correct,
>add it in kern.mk, but only if we're using clang. While this
>option is supported by both clang and gcc, in the future there
>may be changes to clang which change the defaults that require
>a tweak to build our kernel such that other tools in our tree
>will work. Set a good example by forcing -gdwarf-2 only for
>clang builds, and only if the user hasn't specified another
>dwarf level already. Update UPDATING to reflect the changed
>state of affairs. This also keeps us from having to update
>all the ARM kernels to add this, and also keeps us from
>in the future having to update all the MIPS kernels and is
>one less place the user will have to know to do something
>special for clang and one less thing developers will need
>to do when moving an architecture to clang.

MFC r262613:

Merge the projects/clang-sparc64 branch back to head. This brings in
several updates from the llvm and clang trunks to make the sparc64
backend fully functional.

Apart from one patch to sys/sparc64/include/pcpu.h which is still under
discussion, this makes it possible to let clang fully build world and
kernel for sparc64.

Any assistance with testing this on actual sparc64 hardware is greatly
appreciated, as there will unavoidably be bugs left.

Many thanks go to Roman Divacky for his upstream work on getting the
sparc64 backend into shape.

MFC r262985:

Repair a few minor mismerges from r262261 in the clang-sparc64 project
branch. This is also to minimize differences with upstream.

MFC 261991:

Upgrade our copy of llvm/clang to 3.4 release. This version supports
all of the features in the current working draft of the upcoming C++
standard, provisionally named C++1y.

The code generator's performance is greatly increased, and the loop
auto-vectorizer is now enabled at -Os and -O2 in addition to -O3. The
PowerPC backend has made several major improvements to code generation
quality and compile time, and the X86, SPARC, ARM32, Aarch64 and SystemZ
backends have all seen major feature work.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.4/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.4/tools/clang/docs/ReleaseNotes.html>

MFC 262121 (by emaste):

Update lldb for clang/llvm 3.4 import

This commit largely restores the lldb source to the upstream r196259
snapshot with the addition of threaded inferior support and a few bug
fixes.

Specific upstream lldb revisions restored include:
SVN git
181387 779e6ac
181703 7bef4e2
182099 b31044e
182650 f2dcf35
182683 0d91b80
183862 15c1774
183929 99447a6
184177 0b2934b
184948 4dc3761
184954 007e7bc
186990 eebd175

Sponsored by: DARPA, AFRL

MFC 262186 (by emaste):

Fix mismerge in r262121

A break statement was lost in the merge. The error had no functional
impact, but restore it to reduce the diff against upstream.

MFC 262303:

Pull in r197521 from upstream clang trunk (by rdivacky):

Use the integrated assembler by default on FreeBSD/ppc and ppc64.

Requested by: jhibbits

MFC 262611:

Pull in r196874 from upstream llvm trunk:

Fix a crash that occurs when PWD is invalid.

MCJIT needs to be able to run in hostile environments, even when PWD
is invalid. There's no need to crash MCJIT in this case.

The obvious fix is to simply leave MCContext's CompilationDir empty
when PWD can't be determined. This way, MCJIT clients,
and other clients that link with LLVM don't need a valid working directory.

If we do want to guarantee valid CompilationDir, that should be done
only for clients of getCompilationDir(). This is as simple as checking
for an empty string.

The only current use of getCompilationDir is EmitGenDwarfInfo, which
won't conceivably run with an invalid working dir. However, in the
purely hypothetically and untestable case that this happens, the
AT_comp_dir will be omitted from the compilation_unit DIE.

This should help fix assertions occurring with ports-mgmt/tinderbox,
when it is using jails, and sometimes invalidates clang's current
working directory.

Reported by: decke

MFC 262809:

Pull in r203007 from upstream clang trunk:

Don't produce an alias between destructors with different calling conventions.

Fixes pr19007.

(Please note that is an LLVM PR identifier, not a FreeBSD one.)

This should fix Firefox and/or libxul crashes (due to problems with
regparm/stdcall calling conventions) on i386.

Reported by: multiple users on freebsd-current
PR: bin/187103

MFC 263048:

Repair recognition of "CC" as an alias for the C++ compiler, since it
was silently broken by upstream for a Windows-specific use-case.

Apparently some versions of CMake still rely on this archaic feature...

Reported by: rakuco

MFC 263049:

Garbage collect the old way of adding the libstdc++ include directories
in clang's InitHeaderSearch.cpp. This has been superseded by David
Chisnall's commit in r255321.

Moreover, if libc++ is used, the libstdc++ include directories should
not be in the search path at all. These directories are now only used
if you pass -stdlib=libstdc++.