llvm: optionally build compiler-rt, libcxx and libunwind as runtimes (#32476)

* llvm: replace +omp_as_runtime with omp=runtime

* llvm: fetch 'libomp-libflags-as-list.patch' from upstream repo

* llvm: replace 'llvm14-hwloc-ompd.patch' with the official fix from upstream repo

* llvm: fix-up for the black reformatting

* llvm: fetch 'constexpr_longdouble.patch' from upstream repo

* llvm: optionally build libcxx as a runtime

* llvm: fetch 'llvm5-sanitizer-ustat.patch' from upstream repo

* llvm: update 'sanitizer-ipc_perm_mode.patch'

* llvm: refactor compiler conflicts when libcxx=project

* llvm: fetch 'llvm_python_path.patch' from upstream repo

* llvm: update comments and condition for 'xray_buffer_queue-cstddef.patch'

* llvm: optionally build compiler-rt as a runtime

* llvm: fetch 'lldb_external_ncurses-10.patch' from upstream repo

* llvm: fetch 'llvm_py37.patch' from upstream repo

* llvm: rename variant 'internal_unwind' to 'libunwind'

* llvm: optionally build libunwind as a runtime

* llvm: extend the list of maintainers

* llvm: allow for explicit '~clang~flang~libomptarget~lldb~omp_debug~z3'

* llvm: fetch 'llvm5-lld-ELF-Symbols.patch' from FreeBSD port repo

* llvm: fetch most of 'missing-includes.patch' from upstream repo and reuse 'llvm-gcc11.patch'

* llvm: regroup patches for missing include directives and drop compiler constraints for them

* llvm: fetch 'llvm-gcc11.patch' from upstream repo

* llvm: fetch 'no_cyclades.patch' from upstream repo

* llvm: update comments and condition for 'no_cyclades9.patch'

* llvm: rename variant 'omp' to 'openmp'

* llvm: constrain and rename variant 'omp_tsan' to 'libomp_tsan'

* llvm: rename variant 'omp_debug' to 'libomptarget_debug'

* llvm: do not apply same patch twice

* llvm: constrain and document the '*-thread.patch' patches

* llvm: document the '~lld+libomptarget' conflict

* llvm: update comments for the 'D133513.diff' patch

19 files changed, 323 insertions, 463 deletions

diff --git a/share/spack/gitlab/cloud_pipelines/stacks/data-vis-sdk/spack.yaml b/share/spack/gitlab/cloud_pipelines/stacks/data-vis-sdk/spack.yaml
index 178ada4ee5..71a57ce8ac 100644
--- a/share/spack/gitlab/cloud_pipelines/stacks/data-vis-sdk/spack.yaml
+++ b/share/spack/gitlab/cloud_pipelines/stacks/data-vis-sdk/spack.yaml
@@ -14,7 +14,7 @@ spack:
     llvm:
       require: "@14:"
       # Minimize LLVM
-      variants: ~lldb~lld~internal_unwind~polly~compiler-rt~gold
+      variants: "~lldb~lld~polly~gold libunwind=none compiler-rt=none"
     all:
       require: target=x86_64_v3
 
diff --git a/var/spack/repos/builtin/packages/julia/package.py b/var/spack/repos/builtin/packages/julia/package.py
index f955517a20..83fe5578cc 100644
--- a/var/spack/repos/builtin/packages/julia/package.py
+++ b/var/spack/repos/builtin/packages/julia/package.py
@@ -50,15 +50,15 @@ class Julia(MakefilePackage):
     # Note, we just use link_llvm_dylib so that we not only get a libLLVM,
     # but also so that llvm-config --libfiles gives only the dylib. Without
     # it it also gives static libraries, and breaks Julia's build.
-    depends_on("llvm targets=amdgpu,bpf,nvptx,webassembly version_suffix=jl +link_llvm_dylib")
+    depends_on(
+        "llvm"
+        " targets=amdgpu,bpf,nvptx,webassembly"
+        " version_suffix=jl +link_llvm_dylib libunwind=none"
+    )
     depends_on("libuv", when="@:1.7")
     depends_on("libuv-julia@1.42.0", when="@1.8.0:1.8.1")
     depends_on("libuv-julia@1.44.2", when="@1.8.2:")
 
-    # Do not use internal unwind.  We need to use a conflict, because
-    # `internal_unwind` is defined only when `+clang`.
-    conflicts("^llvm+internal_unwind")
-
     with when("@1.9.0:1.9"):
         # libssh2.so.1, libpcre2-8.so.0, mbedtls.so.14, mbedcrypto.so.7, mbedx509.so.1
         # openlibm.so.4, libblastrampoline.so.5, libgit2.so.1.5, libnghttp2.so.14,
diff --git a/var/spack/repos/builtin/packages/llvm/constexpr_longdouble.patch b/var/spack/repos/builtin/packages/llvm/constexpr_longdouble.patch
deleted file mode 100644
index 8b90001d63..0000000000
--- a/var/spack/repos/builtin/packages/llvm/constexpr_longdouble.patch
+++ /dev/null
@@ -1,28 +0,0 @@
-From 3bf63cf3b366d3a57cf5cbad4112a6abf6c0c3b1 Mon Sep 17 00:00:00 2001
-From: Marshall Clow <mclow.lists@gmail.com>
-Date: Tue, 2 Apr 2019 14:46:36 +0000
-Subject: [PATCH] Special case some duration arithmetic for GCC and PPC because
- their long double constant folding is broken. Fixes PR#39696.
-
-llvm-svn: 357478
----
- libcxx/include/thread | 5 +++++
- 1 file changed, 5 insertions(+)
-
-diff --git a/libcxx/include/thread b/libcxx/include/thread
-index df06ff70f8e37f22f4108be8e5e79a38052a11dd..400459ae7f32c4d7cd24b2d85c49d789500e432d 100644
---- a/libcxx/include/thread
-+++ b/libcxx/include/thread
-@@ -434,7 +434,12 @@ sleep_for(const chrono::duration<_Rep, _Period>& __d)
-     using namespace chrono;
-     if (__d > duration<_Rep, _Period>::zero())
-     {
-+#if defined(_LIBCPP_COMPILER_GCC) && (__powerpc__ || __POWERPC__)
-+    //  GCC's long double const folding is incomplete for IBM128 long doubles.
-+        _LIBCPP_CONSTEXPR duration<long double> _Max = duration<long double>(ULLONG_MAX/1000000000ULL) ;
-+#else
-         _LIBCPP_CONSTEXPR duration<long double> _Max = nanoseconds::max();
-+#endif
-         nanoseconds __ns;
-         if (__d < _Max)
-         {
diff --git a/var/spack/repos/builtin/packages/llvm/constexpr_longdouble_9.0.patch b/var/spack/repos/builtin/packages/llvm/constexpr_longdouble_9.0.patch
deleted file mode 100644
index 9a62f27023..0000000000
--- a/var/spack/repos/builtin/packages/llvm/constexpr_longdouble_9.0.patch
+++ /dev/null
@@ -1,38 +0,0 @@
-From d9a42ec98adcb1ebc0c3837715df4e5a50c7ccc0 Mon Sep 17 00:00:00 2001
-From: "Joel E. Denny" <jdenny.ornl@gmail.com>
-Date: Wed, 10 Jun 2020 12:40:43 -0400
-Subject: [PATCH] [libc++] Work around gcc/Power9 bug in `include/thread`
-
-This fixes PR39696, which breaks the libcxx build with gcc (I tested
-7.5.0) on Power9.  This fix was suggested at
-
-https://bugs.llvm.org/show_bug.cgi?id=39696#c38
-
-but never applied.  It just reverts 0583d9ea8d5e, which reverses
-components of the original fix in 3bf63cf3b366, which is correct.
-
-Fixes https://llvm.org/PR39696
-
-Reviewed By: ldionne
-
-Differential Revision: https://reviews.llvm.org/D81438
----
- libcxx/include/thread | 4 ++--
- 1 file changed, 2 insertions(+), 2 deletions(-)
-
-diff --git a/libcxx/include/thread b/libcxx/include/thread
-index 22aa4f201295867cff57b7a944e6b7bd67b22ad3..6eff1800acdbef09eae4417eee977fa350c596ea 100644
---- a/libcxx/include/thread
-+++ b/libcxx/include/thread
-@@ -365,9 +365,9 @@ sleep_for(const chrono::duration<_Rep, _Period>& __d)
-     {
- #if defined(_LIBCPP_COMPILER_GCC) && (__powerpc__ || __POWERPC__)
-     //  GCC's long double const folding is incomplete for IBM128 long doubles.
--        _LIBCPP_CONSTEXPR duration<long double> _Max = nanoseconds::max();
--#else
-         _LIBCPP_CONSTEXPR duration<long double> _Max = duration<long double>(ULLONG_MAX/1000000000ULL) ;
-+#else
-+        _LIBCPP_CONSTEXPR duration<long double> _Max = nanoseconds::max();
- #endif
-         nanoseconds __ns;
-         if (__d < _Max)
diff --git a/var/spack/repos/builtin/packages/llvm/libomp-libflags-as-list.patch b/var/spack/repos/builtin/packages/llvm/libomp-libflags-as-list.patch
deleted file mode 100644
index 995f55a438..0000000000
--- a/var/spack/repos/builtin/packages/llvm/libomp-libflags-as-list.patch
+++ /dev/null
@@ -1,14 +0,0 @@
-diff --git a/openmp/runtime/cmake/LibompHandleFlags.cmake b/openmp/runtime/cmake/LibompHandleFlags.cmake
-index 9e19e59ba17d..f92fa12d851a 100644
---- a/openmp/runtime/cmake/LibompHandleFlags.cmake
-+++ b/openmp/runtime/cmake/LibompHandleFlags.cmake
-@@ -144,7 +144,8 @@ function(libomp_get_libflags libflags)
-   endif()
-   set(libflags_local ${libflags_local} ${LIBOMP_LIBFLAGS})
-   libomp_setup_flags(libflags_local)
--  set(${libflags} ${libflags_local} PARENT_SCOPE)
-+  libomp_string_to_list("${libflags_local}" libflags_local_list)
-+  set(${libflags} ${libflags_local_list} PARENT_SCOPE)
- endfunction()
-
- # Fortran flags
diff --git a/var/spack/repos/builtin/packages/llvm/lldb_external_ncurses-10.patch b/var/spack/repos/builtin/packages/llvm/lldb_external_ncurses-10.patch
deleted file mode 100644
index 34ed0e3cd2..0000000000
--- a/var/spack/repos/builtin/packages/llvm/lldb_external_ncurses-10.patch
+++ /dev/null
@@ -1,31 +0,0 @@
-diff --git a/lldb/include/lldb/Host/Config.h.cmake b/lldb/include/lldb/Host/Config.h.cmake
---- a/lldb/include/lldb/Host/Config.h.cmake
-+++ b/lldb/include/lldb/Host/Config.h.cmake
-@@ -38,6 +38,8 @@
- 
- #cmakedefine01 LLDB_ENABLE_CURSES
- 
-+#cmakedefine01 CURSES_HAVE_NCURSES_CURSES_H
-+
- #cmakedefine01 LLDB_ENABLE_LIBEDIT
- 
- #cmakedefine01 LLDB_ENABLE_LIBXML2
-diff --git a/lldb/source/Core/IOHandlerCursesGUI.cpp b/lldb/source/Core/IOHandlerCursesGUI.cpp
---- a/lldb/source/Core/IOHandlerCursesGUI.cpp
-+++ b/lldb/source/Core/IOHandlerCursesGUI.cpp
-@@ -10,9 +10,14 @@
- #include "lldb/Host/Config.h"
- 
- #if LLDB_ENABLE_CURSES
-+#if CURSES_HAVE_NCURSES_CURSES_H
-+#include <ncurses/curses.h>
-+#include <ncurses/panel.h>
-+#else
- #include <curses.h>
- #include <panel.h>
- #endif
-+#endif
- 
- #if defined(__APPLE__)
- #include <deque>
-
diff --git a/var/spack/repos/builtin/packages/llvm/llvm-gcc11.patch b/var/spack/repos/builtin/packages/llvm/llvm-gcc11.patch
deleted file mode 100644
index 8e081e876e..0000000000
--- a/var/spack/repos/builtin/packages/llvm/llvm-gcc11.patch
+++ /dev/null
@@ -1,9 +0,0 @@
---- a/llvm/utils/benchmark/src/benchmark_register.h
-+++ b/llvm/utils/benchmark/src/benchmark_register.h
-@@ -2,6 +2,7 @@
- #define BENCHMARK_REGISTER_H
- 
- #include <vector>
-+#include <limits>
- 
- #include "check.h"
diff --git a/var/spack/repos/builtin/packages/llvm/llvm14-hwloc-ompd.patch b/var/spack/repos/builtin/packages/llvm/llvm14-hwloc-ompd.patch
deleted file mode 100644
index bdae92e09c..0000000000
--- a/var/spack/repos/builtin/packages/llvm/llvm14-hwloc-ompd.patch
+++ /dev/null
@@ -1,13 +0,0 @@
---- a/openmp/libompd/src/CMakeLists.txt
-+++ b/openmp/libompd/src/CMakeLists.txt
-@@ -44,6 +44,10 @@
-         ${LIBOMP_SRC_DIR}
- )
-
-+if(${LIBOMP_USE_HWLOC})
-+  include_directories(${LIBOMP_HWLOC_INSTALL_DIR}/include)
-+endif()
-+
- INSTALL( TARGETS ompd
-         LIBRARY DESTINATION ${OPENMP_INSTALL_LIBDIR}
-         ARCHIVE DESTINATION ${OPENMP_INSTALL_LIBDIR}
diff --git a/var/spack/repos/builtin/packages/llvm/llvm5-lld-ELF-Symbols.patch b/var/spack/repos/builtin/packages/llvm/llvm5-lld-ELF-Symbols.patch
deleted file mode 100644
index 727647d3b8..0000000000
--- a/var/spack/repos/builtin/packages/llvm/llvm5-lld-ELF-Symbols.patch
+++ /dev/null
@@ -1,33 +0,0 @@
-# Fix lld templates: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=230463
---- a/lld/ELF/Symbols.cpp
-+++ b/lld/ELF/Symbols.cpp
-@@ -383,17 +383,17 @@
-   return B.getName();
- }
- 
--template uint32_t SymbolBody::template getSize<ELF32LE>() const;
--template uint32_t SymbolBody::template getSize<ELF32BE>() const;
--template uint64_t SymbolBody::template getSize<ELF64LE>() const;
--template uint64_t SymbolBody::template getSize<ELF64BE>() const;
-+template uint32_t SymbolBody::getSize<ELF32LE>() const;
-+template uint32_t SymbolBody::getSize<ELF32BE>() const;
-+template uint64_t SymbolBody::getSize<ELF64LE>() const;
-+template uint64_t SymbolBody::getSize<ELF64BE>() const;
- 
--template bool DefinedRegular::template isMipsPIC<ELF32LE>() const;
--template bool DefinedRegular::template isMipsPIC<ELF32BE>() const;
--template bool DefinedRegular::template isMipsPIC<ELF64LE>() const;
--template bool DefinedRegular::template isMipsPIC<ELF64BE>() const;
-+template bool DefinedRegular::isMipsPIC<ELF32LE>() const;
-+template bool DefinedRegular::isMipsPIC<ELF32BE>() const;
-+template bool DefinedRegular::isMipsPIC<ELF64LE>() const;
-+template bool DefinedRegular::isMipsPIC<ELF64BE>() const;
- 
--template uint32_t SharedSymbol::template getAlignment<ELF32LE>() const;
--template uint32_t SharedSymbol::template getAlignment<ELF32BE>() const;
--template uint32_t SharedSymbol::template getAlignment<ELF64LE>() const;
--template uint32_t SharedSymbol::template getAlignment<ELF64BE>() const;
-+template uint32_t SharedSymbol::getAlignment<ELF32LE>() const;
-+template uint32_t SharedSymbol::getAlignment<ELF32BE>() const;
-+template uint32_t SharedSymbol::getAlignment<ELF64LE>() const;
-+template uint32_t SharedSymbol::getAlignment<ELF64BE>() const;
diff --git a/var/spack/repos/builtin/packages/llvm/llvm5-sanitizer-ustat.patch b/var/spack/repos/builtin/packages/llvm/llvm5-sanitizer-ustat.patch
deleted file mode 100644
index 531a3c5d6d..0000000000
--- a/var/spack/repos/builtin/packages/llvm/llvm5-sanitizer-ustat.patch
+++ /dev/null
@@ -1,25 +0,0 @@
-# <sys/ustat.h> has been removed from glibc 2.28,
-# backport fix from llvm-6.0.1:
---- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cc
-+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cc
-@@ -159,1 +159,0 @@
--#include <sys/ustat.h>
-@@ -252,5 +252,17 @@
- 
- #if SANITIZER_LINUX && !SANITIZER_ANDROID
--  unsigned struct_ustat_sz = sizeof(struct ustat);
-+  // Use pre-computed size of struct ustat to avoid <sys/ustat.h> which
-+  // has been removed from glibc 2.28.
-+#if defined(__aarch64__) || defined(__s390x__) || defined (__mips64) \
-+  || defined(__powerpc64__) || defined(__arch64__) || defined(__sparcv9) \
-+  || defined(__x86_64__)
-+#define SIZEOF_STRUCT_USTAT 32
-+#elif defined(__arm__) || defined(__i386__) || defined(__mips__) \
-+  || defined(__powerpc__) || defined(__s390__)
-+#define SIZEOF_STRUCT_USTAT 20
-+#else
-+#error Unknown size of struct ustat
-+#endif
-+  unsigned struct_ustat_sz = SIZEOF_STRUCT_USTAT;
-   unsigned struct_rlimit64_sz = sizeof(struct rlimit64);
-   unsigned struct_statvfs64_sz = sizeof(struct statvfs64);
diff --git a/var/spack/repos/builtin/packages/llvm/llvm_py37.patch b/var/spack/repos/builtin/packages/llvm/llvm_py37.patch
deleted file mode 100644
index 478be87994..0000000000
--- a/var/spack/repos/builtin/packages/llvm/llvm_py37.patch
+++ /dev/null
@@ -1,37 +0,0 @@
-From ecdefed7f6ba11421fe1ecc6c13a135ab7bcda73 Mon Sep 17 00:00:00 2001
-From: Pavel Labath <labath@google.com>
-Date: Mon, 23 Jul 2018 11:37:36 +0100
-Subject: [PATCH] Fix PythonString::GetString for >=python-3.7
-
-The return value of PyUnicode_AsUTF8AndSize is now "const char *".
----
- .../Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp  | 6 ++++--
- 1 file changed, 4 insertions(+), 2 deletions(-)
-
-diff --git a/tools/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp b/tools/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
-index 6a9d57d5a..94f16b2c7 100644
---- a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
-+++ b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
-@@ -404,14 +404,16 @@ llvm::StringRef PythonString::GetString() const {
-     return llvm::StringRef();
- 
-   Py_ssize_t size;
--  char *c;
-+  const char *data;
- 
- #if PY_MAJOR_VERSION >= 3
--  c = PyUnicode_AsUTF8AndSize(m_py_obj, &size);
-+  data = PyUnicode_AsUTF8AndSize(m_py_obj, &size);
- #else
-+  char *c;
-   PyString_AsStringAndSize(m_py_obj, &c, &size);
-+  data = c;
- #endif
--  return llvm::StringRef(c, size);
-+  return llvm::StringRef(data, size);
- }
- 
- size_t PythonString::GetSize() const {
--- 
-2.18.0.233.g985f88cf7e-goog
-
diff --git a/var/spack/repos/builtin/packages/llvm/llvm_python_path.patch b/var/spack/repos/builtin/packages/llvm/llvm_python_path.patch
deleted file mode 100644
index 9f821cc365..0000000000
--- a/var/spack/repos/builtin/packages/llvm/llvm_python_path.patch
+++ /dev/null
@@ -1,14 +0,0 @@
-diff --git a/compiler-rt/cmake/Modules/AddCompilerRT.cmake b/compiler-rt/cmake/Modules/AddCompilerRT.cmake
-index dab55707338..6f4c6791141 100644
---- a/compiler-rt/cmake/Modules/AddCompilerRT.cmake
-+++ b/compiler-rt/cmake/Modules/AddCompilerRT.cmake
-@@ -612,6 +612,9 @@ macro(add_custom_libcxx name prefix)
-     CMAKE_OBJDUMP
-     CMAKE_STRIP
-     CMAKE_SYSROOT
-+    PYTHON_EXECUTABLE
-+    Python3_EXECUTABLE
-+    Python2_EXECUTABLE
-     CMAKE_SYSTEM_NAME)
-   foreach(variable ${PASSTHROUGH_VARIABLES})
-     get_property(is_value_set CACHE ${variable} PROPERTY VALUE SET)
diff --git a/var/spack/repos/builtin/packages/llvm/missing-includes.patch b/var/spack/repos/builtin/packages/llvm/missing-includes.patch
deleted file mode 100644
index e88b8fcfde..0000000000
--- a/var/spack/repos/builtin/packages/llvm/missing-includes.patch
+++ /dev/null
@@ -1,23 +0,0 @@
-# https://github.com/spack/spack/issues/24270 (This hunk is upstream since llvm-10)
---- a/llvm/include/llvm/Demangle/MicrosoftDemangleNodes.h
-+++ b/llvm/include/llvm/Demangle/MicrosoftDemangleNodes.h
-@@ -4,6 +4,8 @@
- #include "llvm/Demangle/Compiler.h"
- #include "llvm/Demangle/StringView.h"
- #include <array>
-+#include <cstdint>
-+#include <string>
- 
- class OutputStream;
- 
-# https://github.com/spack/spack/pull/27233
---- a/llvm/utils/benchmark/src/benchmark_register.h
-+++ b/llvm/utils/benchmark/src/benchmark_register.h
-@@ -2,6 +2,7 @@
- #define BENCHMARK_REGISTER_H
- 
- #include <vector>
-+#include <limits>
- 
- #include "check.h"
- 
diff --git a/var/spack/repos/builtin/packages/llvm/no_cyclades.patch b/var/spack/repos/builtin/packages/llvm/no_cyclades.patch
deleted file mode 100644
index 10f9d0796b..0000000000
--- a/var/spack/repos/builtin/packages/llvm/no_cyclades.patch
+++ /dev/null
@@ -1,81 +0,0 @@
-diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_ioctl.inc b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_ioctl.inc
---- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_ioctl.inc
-+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_ioctl.inc
-@@ -370,15 +370,6 @@
- 
- #if SANITIZER_GLIBC
-   // _(SIOCDEVPLIP, WRITE, struct_ifreq_sz); // the same as EQL_ENSLAVE
--  _(CYGETDEFTHRESH, WRITE, sizeof(int));
--  _(CYGETDEFTIMEOUT, WRITE, sizeof(int));
--  _(CYGETMON, WRITE, struct_cyclades_monitor_sz);
--  _(CYGETTHRESH, WRITE, sizeof(int));
--  _(CYGETTIMEOUT, WRITE, sizeof(int));
--  _(CYSETDEFTHRESH, NONE, 0);
--  _(CYSETDEFTIMEOUT, NONE, 0);
--  _(CYSETTHRESH, NONE, 0);
--  _(CYSETTIMEOUT, NONE, 0);
-   _(EQL_EMANCIPATE, WRITE, struct_ifreq_sz);
-   _(EQL_ENSLAVE, WRITE, struct_ifreq_sz);
-   _(EQL_GETMASTRCFG, WRITE, struct_ifreq_sz);
-diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
---- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
-+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
-@@ -983,7 +983,6 @@
- 
- #if SANITIZER_LINUX && !SANITIZER_ANDROID
- extern unsigned struct_ax25_parms_struct_sz;
--extern unsigned struct_cyclades_monitor_sz;
- extern unsigned struct_input_keymap_entry_sz;
- extern unsigned struct_ipx_config_data_sz;
- extern unsigned struct_kbdiacrs_sz;
-@@ -1328,15 +1327,6 @@
- #endif  // SANITIZER_LINUX
- 
- #if SANITIZER_LINUX && !SANITIZER_ANDROID
--extern unsigned IOCTL_CYGETDEFTHRESH;
--extern unsigned IOCTL_CYGETDEFTIMEOUT;
--extern unsigned IOCTL_CYGETMON;
--extern unsigned IOCTL_CYGETTHRESH;
--extern unsigned IOCTL_CYGETTIMEOUT;
--extern unsigned IOCTL_CYSETDEFTHRESH;
--extern unsigned IOCTL_CYSETDEFTIMEOUT;
--extern unsigned IOCTL_CYSETTHRESH;
--extern unsigned IOCTL_CYSETTIMEOUT;
- extern unsigned IOCTL_EQL_EMANCIPATE;
- extern unsigned IOCTL_EQL_ENSLAVE;
- extern unsigned IOCTL_EQL_GETMASTRCFG;
-diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cpp
---- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cpp
-+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cpp
-@@ -143,7 +143,6 @@
- # include <sys/procfs.h>
- #endif
- #include <sys/user.h>
--#include <linux/cyclades.h>
- #include <linux/if_eql.h>
- #include <linux/if_plip.h>
- #include <linux/lp.h>
-@@ -460,7 +459,6 @@
- 
- #if SANITIZER_GLIBC
-   unsigned struct_ax25_parms_struct_sz = sizeof(struct ax25_parms_struct);
--  unsigned struct_cyclades_monitor_sz = sizeof(struct cyclades_monitor);
- #if EV_VERSION > (0x010000)
-   unsigned struct_input_keymap_entry_sz = sizeof(struct input_keymap_entry);
- #else
-@@ -824,15 +822,6 @@
- #endif // SANITIZER_LINUX
- 
- #if SANITIZER_LINUX && !SANITIZER_ANDROID
--  unsigned IOCTL_CYGETDEFTHRESH = CYGETDEFTHRESH;
--  unsigned IOCTL_CYGETDEFTIMEOUT = CYGETDEFTIMEOUT;
--  unsigned IOCTL_CYGETMON = CYGETMON;
--  unsigned IOCTL_CYGETTHRESH = CYGETTHRESH;
--  unsigned IOCTL_CYGETTIMEOUT = CYGETTIMEOUT;
--  unsigned IOCTL_CYSETDEFTHRESH = CYSETDEFTHRESH;
--  unsigned IOCTL_CYSETDEFTIMEOUT = CYSETDEFTIMEOUT;
--  unsigned IOCTL_CYSETTHRESH = CYSETTHRESH;
--  unsigned IOCTL_CYSETTIMEOUT = CYSETTIMEOUT;
-   unsigned IOCTL_EQL_EMANCIPATE = EQL_EMANCIPATE;
-   unsigned IOCTL_EQL_ENSLAVE = EQL_ENSLAVE;
-   unsigned IOCTL_EQL_GETMASTRCFG = EQL_GETMASTRCFG;
diff --git a/var/spack/repos/builtin/packages/llvm/no_cyclades9.patch b/var/spack/repos/builtin/packages/llvm/no_cyclades9.patch
index 7532865e6d..55cb70d1e4 100644
--- a/var/spack/repos/builtin/packages/llvm/no_cyclades9.patch
+++ b/var/spack/repos/builtin/packages/llvm/no_cyclades9.patch
@@ -1,3 +1,8 @@
+# This is a backport of https://reviews.llvm.org/D102059.
+#
+# We need the patch to be applicable when="@:9" and, therefore, cannot fetch
+# it from the upstream repo.
+
 --- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_ioctl.inc
 +++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_ioctl.inc
 @@ -370,9 +370,0 @@
diff --git a/var/spack/repos/builtin/packages/llvm/package.py b/var/spack/repos/builtin/packages/llvm/package.py
index 1b17cbe7d0..7af5766b09 100644
--- a/var/spack/repos/builtin/packages/llvm/package.py
+++ b/var/spack/repos/builtin/packages/llvm/package.py
@@ -26,7 +26,7 @@ class Llvm(CMakePackage, CudaPackage):
     url = "https://github.com/llvm/llvm-project/archive/llvmorg-7.1.0.tar.gz"
     list_url = "https://releases.llvm.org/download.html"
     git = "https://github.com/llvm/llvm-project"
-    maintainers("trws", "haampie")
+    maintainers("trws", "haampie", "skosukhin")
 
     tags = ["e4s"]
 
@@ -82,44 +82,72 @@ class Llvm(CMakePackage, CudaPackage):
     variant(
         "clang", default=True, description="Build the LLVM C/C++/Objective-C compiler frontend"
     )
+
     variant(
         "flang",
         default=False,
-        when="@11: +clang",
         description="Build the LLVM Fortran compiler frontend "
         "(experimental - parser only, needs GCC)",
     )
-    variant("lldb", default=True, when="+clang", description="Build the LLVM debugger")
+    conflicts("+flang", when="@:10")
+    conflicts("+flang", when="~clang")
+
+    variant("lldb", default=True, description="Build the LLVM debugger")
+    conflicts("+lldb", when="~clang")
+
     variant("lld", default=True, description="Build the LLVM linker")
     variant("mlir", default=False, when="@10:", description="Build with MLIR support")
     variant(
-        "internal_unwind", default=True, when="+clang", description="Build the libcxxabi libunwind"
+        "libunwind",
+        values=(
+            "none",
+            conditional("project", when="@:15"),
+            conditional("runtime", when="+clang @6:"),
+        ),
+        default="runtime",
+        description="Build the LLVM unwinder library"
+        "either as a runtime (with just-build Clang) "
+        "or as a project (with the compiler in use)",
     )
     variant(
         "polly",
         default=True,
-        description="Build the LLVM polyhedral optimization plugin, " "only builds for 3.7.0+",
-    )
-    variant(
-        "libcxx", default=True, when="+clang", description="Build the LLVM C++ standard library"
+        description="Build the LLVM polyhedral optimization plugin, only builds for 3.7.0+",
     )
     variant(
-        "libomptarget",
-        default=True,
-        when="+clang",
-        description="Build the OpenMP offloading library",
+        "libcxx",
+        values=(
+            "none",
+            conditional("project", when="@:15"),
+            conditional("runtime", when="+clang @6:"),
+        ),
+        default="runtime",
+        description="Build the LLVM C++ standard library "
+        "either as a runtime (with just-build Clang) "
+        "or as a project (with the compiler in use)",
     )
+
+    variant("libomptarget", default=True, description="Build the OpenMP offloading library")
+    conflicts("+libomptarget", when="~clang")
+
     variant(
-        "omp_debug",
+        "libomptarget_debug",
         default=False,
-        when="+libomptarget",
-        description="Include debugging code in OpenMP runtime libraries",
+        description="Allow debug output with the environment variable LIBOMPTARGET_DEBUG=1",
     )
+    conflicts("+libomptarget_debug", when="~libomptarget")
+
     variant(
         "compiler-rt",
-        when="+clang",
-        default=True,
-        description="Build LLVM compiler runtime, including sanitizers",
+        values=(
+            "none",
+            conditional("project", when="+clang"),
+            conditional("runtime", when="+clang @6:"),
+        ),
+        default="runtime",
+        description="Build the LLVM compiler runtime, including sanitizers, "
+        "either as a runtime (with just-build Clang) "
+        "or as a project (with the compiler in use)",
     )
     variant(
         "gold",
@@ -170,16 +198,19 @@ class Llvm(CMakePackage, CudaPackage):
         multi=True,
     )
     variant(
-        "omp_tsan",
+        "libomp_tsan",
         default=False,
-        when="@6:",
+        # Added in https://reviews.llvm.org/D13072
+        # Removed in https://reviews.llvm.org/D103767
+        when="@4:12",
         description="Build with OpenMP capable thread sanitizer",
     )
     variant(
-        "omp_as_runtime",
-        default=True,
-        when="+clang @12:",
-        description="Build OpenMP runtime via ENABLE_RUNTIME by just-built Clang",
+        "openmp",
+        values=("project", conditional("runtime", when="+clang @12:")),
+        default="runtime",
+        description="Build OpenMP either as a runtime (with just-build Clang) "
+        "or as a project (with the compiler in use)",
     )
     variant(
         "code_signing",
@@ -195,9 +226,10 @@ class Llvm(CMakePackage, CudaPackage):
         description="Add shared library symbol version",
         when="@13:",
     )
-    variant(
-        "z3", default=False, when="+clang @8:", description="Use Z3 for the clang static analyzer"
-    )
+    variant("z3", default=False, description="Use Z3 for the clang static analyzer")
+    conflicts("+z3", when="@:7")
+    conflicts("+z3", when="~clang")
+
     variant(
         "zstd",
         default=False,
@@ -224,6 +256,12 @@ class Llvm(CMakePackage, CudaPackage):
     depends_on("cmake@3.4.3:", type="build")
     depends_on("cmake@3.13.4:", type="build", when="@12:")
     depends_on("cmake@3.20:", type="build", when="@16:")
+    with when("@:10"):
+        # Versions 10 and older cannot build runtimes with cmake@3.17:
+        # See https://reviews.llvm.org/D77284
+        for runtime in ["libunwind", "libcxx", "compiler-rt"]:
+            depends_on("cmake@:3.16", type="build", when="{0}=runtime".format(runtime))
+        del runtime
     depends_on("python", when="~python", type="build")
     depends_on("pkgconfig", type="build")
 
@@ -268,17 +306,41 @@ class Llvm(CMakePackage, CudaPackage):
     # Internal compiler error on gcc 8.4 on aarch64 https://bugzilla.redhat.com/show_bug.cgi?id=1958295
     conflicts("%gcc@8.4:8.4.9", when="@12: target=aarch64:")
 
-    # When these versions are concretized, but not explicitly with +libcxx, these
-    # conflicts will enable clingo to set ~libcxx, making the build successful:
-
-    # libc++ of LLVM13, see https://libcxx.llvm.org/#platform-and-compiler-support
-    # @13 does not support %gcc@:10 https://bugs.llvm.org/show_bug.cgi?id=51359#c1
-    # GCC    11     - latest stable release per GCC release page
-    # Clang: 11, 12 - latest two stable releases per LLVM release page
-    # AppleClang 12 - latest stable release per Xcode release page
-    conflicts("%gcc@:10", when="@13:+libcxx")
-    conflicts("%clang@:10", when="@13:+libcxx")
-    conflicts("%apple-clang@:11", when="@13:+libcxx")
+    # libcxx=project imposes compiler conflicts
+    # see https://libcxx.llvm.org/#platform-and-compiler-support for the latest release
+    # and https://github.com/llvm/www-releases for older releases
+    with when("libcxx=project"):
+        for v, compiler_conflicts in {
+            "@7:": {"clang": "@:3.4", "gcc": "@:4.6"},
+            "@9:": {"clang": "@:3.4", "gcc": "@:4"},
+            "@11:": {"clang": "@:3", "gcc": "@:4"},
+            "@13:": {"clang": "@:10", "gcc": "@:10", "apple-clang": "@:11"},
+            "@14:": {
+                "clang": "@:11",
+                "gcc": "@:10",
+                "apple-clang": "@:11",
+                "xlc": "@:17.0",
+                "xlc_r": "@:17.0",
+            },
+            "@15:": {
+                "clang": "@:12",
+                "gcc": "@:11",
+                "apple-clang": "@:12",
+                "xlc": "@:17.0",
+                "xlc_r": "@:17.0",
+            },
+            "@16:": {
+                "clang": "@:13",
+                "gcc": "@:11",
+                "apple-clang": "@:13",
+                "xlc": "@:17.0",
+                "xlc_r": "@:17.0",
+            },
+        }.items():
+            with when(v):
+                for comp in spack.compilers.supported_compilers():
+                    conflicts("%{0}{1}".format(comp, compiler_conflicts.get(comp, "")))
+        del v, compiler_conflicts, comp
 
     # libomptarget
     conflicts("+cuda", when="@15:")  # +cuda variant is obselete since LLVM 15
@@ -287,6 +349,7 @@ class Llvm(CMakePackage, CudaPackage):
         when="+libomptarget",
         msg="Non-host backends needed for offloading, set targets=all",
     )
+    # See https://github.com/spack/spack/pull/32476#issuecomment-1573770361
     conflicts("~lld", when="+libomptarget")
 
     # cuda_arch value must be specified
@@ -297,82 +360,160 @@ class Llvm(CMakePackage, CudaPackage):
     # Fixed in upstream versions of both
     conflicts("^cmake@3.19.0", when="@6:11.0.0")
 
-    # sys/ustat.h has been removed in favour of statfs from glibc-2.28. Use fixed sizes:
-    patch("llvm5-sanitizer-ustat.patch", when="@4:6.0.0+compiler-rt")
-
     # Fix lld templates: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=230463
-    patch("llvm5-lld-ELF-Symbols.patch", when="@5+lld%clang@7:")
-
-    # Fix missing std:size_t in 'llvm@4:5' when built with '%clang@7:'
-    patch("xray_buffer_queue-cstddef.patch", when="@4:5+compiler-rt%clang@7:")
+    patch(
+        "https://raw.githubusercontent.com/freebsd/freebsd-ports/f8f9333d8e1e5a7a6b28c5ef0ca73785db06136e/devel/llvm50/files/lld/patch-tools_lld_ELF_Symbols.cpp",
+        sha256="c81a50c1b6b78d359c0ce3b88914477f4f2a85b8dbfa7ac745b9e7eb4e53931b",
+        when="@5+lld%clang@7:",
+    )
 
-    # https://github.com/llvm/llvm-project/commit/947f9692440836dcb8d88b74b69dd379d85974ce
-    patch("sanitizer-ipc_perm_mode.patch", when="@5:7+compiler-rt%clang@11:")
-    patch("sanitizer-ipc_perm_mode.patch", when="@5:9+compiler-rt%gcc@9:")
+    # Add missing include directives for the standard headers (the real need for the following
+    # patches depends on the implementation of the standard C++ library, the headers, however, must
+    # be included according to the standard, therefore, we apply the patches regardless of the
+    # compiler and compiler version).
+    #
+    # fix missing ::size_t in 'llvm@4:5'
+    # see comments in the patch file
+    patch(
+        "xray_buffer_queue-cstddef.patch",
+        # we do not cover compiler-rt=runtime because it is not supported when @:5
+        when="@4:5 compiler-rt=project",
+    )
+    #
+    # see https://reviews.llvm.org/D64937
+    # see https://github.com/spack/spack/issues/24270
+    patch(
+        "https://github.com/llvm/llvm-project/commit/b288d90b39f4b905c02092a9bfcfd6d78f99b191.patch?full_index=1",
+        sha256="2028d52e1a39326bb48fb7463132bbfe7fb4fa18f1adfeea9c3ed0320ed49564",
+        when="@8:9.0.0",
+    )
+    #
+    # committed upstream without a review
+    # see https://github.com/llvm/llvm-project/commit/b498303066a63a203d24f739b2d2e0e56dca70d1
+    # see https://github.com/spack/spack/pull/28547
+    patch(
+        "https://github.com/llvm/llvm-project/commit/b498303066a63a203d24f739b2d2e0e56dca70d1.patch?full_index=1",
+        sha256="514926d661635de47972c7d403c9c4669235aa51e22e56d44676d2a2709179b6",
+        when="@8:11",
+    )
 
-    # github.com/spack/spack/issues/24270: MicrosoftDemangle for %gcc@10: and %clang@13:
-    patch("missing-includes.patch", when="@8")
+    # fix building of older versions of llvm with newer versions of glibc
+    for compiler_rt_as in ["project", "runtime"]:
+        with when("compiler-rt={0}".format(compiler_rt_as)):
+            # sys/ustat.h has been removed in favour of statfs from glibc-2.28
+            # see https://reviews.llvm.org/D47281
+            patch(
+                "https://github.com/llvm/llvm-project/commit/383fe5c8668f63ef21c646b43f48da9fa41aa100.patch?full_index=1",
+                sha256="66f01ac1769a6815aba09d6f4347ac1744f77f82ec9578a1158b24daca7a89e6",
+                when="@4:6.0.0",
+            )
+            # fix sanitizer-common build with glibc 2.31
+            # see https://reviews.llvm.org/D70662
+            patch("sanitizer-ipc_perm_mode.patch", when="@5:9")
+    del compiler_rt_as
 
     # Backport from llvm upstream gcc ppc const expr long double issue
     # see https://bugs.llvm.org/show_bug.cgi?id=39696
-    # This fix was initially commited (3bf63cf3b366) for the 9.0 release
+    # This fix was initially committed (3bf63cf3b366) for the 9.0 release
     # but was then broken (0583d9ea8d5e) prior to the 9.0 release and
     # eventually unbroken (d9a42ec98adc) for the 11.0 release.  The first
     # patch backports the original correct fix to previous releases.  The
     # second patch backports the un-breaking of the original fix.
-    patch("constexpr_longdouble.patch", when="@6:8+libcxx")
-    patch("constexpr_longdouble_9.0.patch", when="@9:10+libcxx")
+    for libcxx_as in ["project", "runtime"]:
+        with when("libcxx={0}".format(libcxx_as)):
+            patch(
+                "https://github.com/llvm/llvm-project/commit/3bf63cf3b366d3a57cf5cbad4112a6abf6c0c3b1.patch?full_index=1",
+                sha256="e56489a4bcf3c3636e206adca366bfcda2722ad81a5fa9a0360faed63933191a",
+                when="@6:8",
+            )
+            patch(
+                "https://github.com/llvm/llvm-project/commit/d9a42ec98adcb1ebc0c3837715df4e5a50c7ccc0.patch?full_index=1",
+                sha256="50bfc4e82c02bb5b7739990f363d99b1e43d5d11a5104f6aabbc303ebce6fbe3",
+                when="@9:10",
+            )
+    del libcxx_as
 
-    # Backport from llvm master; see
-    # https://bugs.llvm.org/show_bug.cgi?id=38233
-    # for a bug report about this problem in llvm master.
-    patch("llvm_py37.patch", when="@4:6 ^python@3.7:")
+    # Backport from llvm to fix issues related to Python 3.7
+    # see https://bugs.llvm.org/show_bug.cgi?id=38233
+    patch(
+        "https://github.com/llvm/llvm-project/commit/5457b426f5e15a29c0acc8af1a476132f8be2a36.patch?full_index=1",
+        sha256="7a1e4aa80760167807255c3e3121b1281bfcf532396b2d8fb3dce021f3f18758",
+        when="@4:6+python+lldb ^python@3.7:",
+    )
 
-    # https://github.com/spack/spack/issues/19625,
-    # merged in llvm-11.0.0_rc2, first available in 12.0.0
-    patch("lldb_external_ncurses-10.patch", when="@10.0.0:11+lldb")
+    # fix building on SUSE (with panel.h being in /usr/include/ncurses/)
+    # see https://reviews.llvm.org/D85219
+    # see https://github.com/spack/spack/issues/19625
+    patch(
+        "https://github.com/llvm/llvm-project/commit/c952ec15d38843b69e22dfd7b0665304a0459f9f.patch?full_index=1",
+        sha256="66932ba31b5bf8808ea112e42cfd79b2480a4936e711771c06ce851eac429b2c",
+        when="@10:11+lldb",
+    )
 
-    # https://github.com/spack/spack/issues/19908
-    # merged in llvm main prior to 12.0.0
-    patch("llvm_python_path.patch", when="@:11")
+    # honor Python2_EXECUTABLE and Python3_EXECUTABLE when they are passed to cmake
+    # see https://reviews.llvm.org/D91536
+    patch(
+        "https://github.com/llvm/llvm-project/commit/16de50895e96adbe261a5ce2498366bda7b3fccd.patch?full_index=1",
+        sha256="0e121ed460aa6e117f9f5f339d597a96c0fe4f97dc2209aba47b43ffc831ea24",
+        # The patch is applicable only starting version 7.0.0 (the older version might require a
+        # different patch addressing https://github.com/spack/spack/issues/19908). It looks like
+        # the patched function is used only if both compiler-rt and libcxx are enabled but we keep
+        # it simple:
+        when="@7:11",
+    )
 
     # Workaround for issue https://github.com/spack/spack/issues/18197
     patch("llvm7_intel.patch", when="@7 %intel@18.0.2,19.0.0:19.1.99")
 
     # Remove cyclades support to build against newer kernel headers
     # https://reviews.llvm.org/D102059
-    patch("no_cyclades.patch", when="@10:12.0.0")
-    patch("no_cyclades9.patch", when="@6:9")
-
-    patch("llvm-gcc11.patch", when="@9:11%gcc@11:")
-
-    # add -lpthread to build OpenMP libraries with Fujitsu compiler
-    patch("llvm12-thread.patch", when="@12 %fj")
-
-    # add -lpthread to build OpenMP libraries
-    patch("llvm13-14-thread.patch", when="@13:14")
-    patch("llvm15-thread.patch", when="@15")
+    patch(
+        "https://github.com/llvm/llvm-project/commit/68d5235cb58f988c71b403334cd9482d663841ab.patch?full_index=1",
+        sha256="742501723642675075e617f3c38339961b2c7b6fd8290dbffc52239ab0783317",
+        when="@10:12.0.0",
+    )
+    # The patch above is not applicable when "@:9" due to the file renaming and reformatting. The
+    # following patch is applicable starting at least version 5.0.0, the oldest we try to support.
+    patch("no_cyclades9.patch", when="@5:9")
+
+    with when("+libomptarget"):
+        # libomptarget makes use of multithreading via the standard C++ library (e.g.
+        # std::call_once), which, depending on the platform and the implementation of the standard
+        # library, might or might not require linking to libpthread (note that the failure might
+        # happen at the linking time as well as at the runtime). In some cases, the required linker
+        # flag comes as a transitive dependency (e.g. from the static LLVMSupport component). The
+        # following patches enforce linking to the thread library that is relevant for the system,
+        # which might lead to overlinking in some cases though.
+        # TODO: figure out why we do not use LLVM_PTHREAD_LIB but run find_package(Threads), at
+        #  least for newer versions (the solution must work with both openmp=runtime and
+        #  openmp=project)
+        patch("llvm12-thread.patch", when="@12")
+        patch("llvm13-14-thread.patch", when="@13:14")
+        patch("llvm15-thread.patch", when="@15")
 
     # avoid build failed with Fujitsu compiler
     patch("llvm13-fujitsu.patch", when="@13 %fj")
 
     # patch for missing hwloc.h include for libompd
-    patch("llvm14-hwloc-ompd.patch", when="@14")
-
-    # make libflags a list in openmp subproject when ~omp_as_runtime
-    patch("libomp-libflags-as-list.patch", when="@3.7:14")
+    # see https://reviews.llvm.org/D123888
+    patch(
+        "https://github.com/llvm/llvm-project/commit/91ccd8248c85385a5654c63c302a37d97f811bab.patch?full_index=1",
+        sha256="b216cff38659c176c5381e9dda3252edbb204e6f6f1f33e843a9ebcc42732e5d",
+        when="@14 openmp=runtime",
+    )
 
-    # Add missing include leading to build fail with clang
+    # make libflags a list in openmp subproject when openmp=project
+    # see https://reviews.llvm.org/D125370
     patch(
-        "https://github.com/llvm/llvm-project/commit/b498303066a63a203d24f739b2d2e0e56dca70d1.patch?full_index=1",
-        sha256="514926d661635de47972c7d403c9c4669235aa51e22e56d44676d2a2709179b6",
-        when="@8:11",
+        "https://github.com/llvm/llvm-project/commit/e27ce281399dca8b08b6ca593172a1bd5dbdd5c1.patch?full_index=1",
+        sha256="6f0cfa55e3ed17ee33346b0a5bca8092adcc1dc75ca712ab83901755fba9767e",
+        when="@3.7:14 openmp=project",
     )
 
     # fix detection of LLDB_PYTHON_EXE_RELATIVE_PATH
     # see https://reviews.llvm.org/D133513
-    # TODO: adjust version constraint and switch to fetching from the upstream GitHub repo
-    #  when/if the bugfix is merged
+    # TODO: the patch is not applicable after https://reviews.llvm.org/D141042 but it is not clear
+    #  yet whether we need a version of it for when="@16:"
     patch("D133513.diff", level=0, when="@14:15+lldb+python")
 
     # Fix hwloc@:2.3 (Conditionally disable hwloc@2.0 and hwloc@2.4 code)
@@ -382,6 +523,14 @@ class Llvm(CMakePackage, CudaPackage):
         when="@14:15",
     )
 
+    # Fix false positive detection of a target when building compiler-rt as a runtime
+    # https://reviews.llvm.org/D127975
+    patch(
+        "https://github.com/llvm/llvm-project/commit/9f1d90bf91570efa124c4a86cd033de374d1049a.patch?full_index=1",
+        sha256="1f4287465b3e499911e039e6cc2f395b8cb00eb8a0a223fa0db3704ba77f9969",
+        when="@13:14 compiler-rt=runtime",
+    )
+
     # The functions and attributes below implement external package
     # detection for LLVM. See:
     #
@@ -618,7 +767,7 @@ class Llvm(CMakePackage, CudaPackage):
                     ),
                 ]
             )
-            if "+omp_as_runtime" in spec:
+            if "openmp=runtime" in spec:
                 cmake_args.extend(
                     [
                         define("LIBOMPTARGET_NVPTX_ENABLE_BCLIB", True),
@@ -637,7 +786,7 @@ class Llvm(CMakePackage, CudaPackage):
                 ]
             )
 
-        cmake_args.append(from_variant("LIBOMPTARGET_ENABLE_DEBUG", "omp_debug"))
+        cmake_args.append(from_variant("LIBOMPTARGET_ENABLE_DEBUG", "libomptarget_debug"))
 
         if "+lldb" in spec:
             projects.append("lldb")
@@ -663,9 +812,9 @@ class Llvm(CMakePackage, CudaPackage):
         if "+clang" in spec:
             projects.append("clang")
             projects.append("clang-tools-extra")
-            if "+omp_as_runtime" in spec:
+            if "openmp=runtime" in spec:
                 runtimes.append("openmp")
-            else:
+            elif "openmp=project" in spec:
                 projects.append("openmp")
 
             if "+libomptarget" in spec:
@@ -682,23 +831,20 @@ class Llvm(CMakePackage, CudaPackage):
             projects.append("flang")
         if "+lld" in spec:
             projects.append("lld")
-        if "+compiler-rt" in spec:
-            if self.spec.satisfies("@15.0.0:"):
-                runtimes.append("compiler-rt")
-            else:
-                projects.append("compiler-rt")
-        if "+libcxx" in spec:
-            if self.spec.satisfies("@15.0.0:"):
-                runtimes.extend(["libcxx", "libcxxabi"])
-            else:
-                projects.extend(["libcxx", "libcxxabi"])
+        if "compiler-rt=runtime" in spec:
+            runtimes.append("compiler-rt")
+        elif "compiler-rt=project" in spec:
+            projects.append("compiler-rt")
+        if "libcxx=runtime" in spec:
+            runtimes.extend(["libcxx", "libcxxabi"])
+        elif "libcxx=project" in spec:
+            projects.extend(["libcxx", "libcxxabi"])
         if "+mlir" in spec:
             projects.append("mlir")
-        if "+internal_unwind" in spec:
-            if self.spec.satisfies("@15.0.0:"):
-                runtimes.append("libunwind")
-            else:
-                projects.append("libunwind")
+        if "libunwind=runtime" in spec:
+            runtimes.append("libunwind")
+        elif "libunwind=project" in spec:
+            projects.append("libunwind")
         if "+polly" in spec:
             projects.append("polly")
             cmake_args.append(define("LINK_POLLY_INTO_TOOLS", True))
@@ -718,7 +864,7 @@ class Llvm(CMakePackage, CudaPackage):
 
         cmake_args.append(define("LLVM_TARGETS_TO_BUILD", get_llvm_targets_to_build(spec)))
 
-        cmake_args.append(from_variant("LIBOMP_TSAN_SUPPORT", "omp_tsan"))
+        cmake_args.append(from_variant("LIBOMP_TSAN_SUPPORT", "libomp_tsan"))
 
         if self.compiler.name == "gcc":
             cmake_args.append(define("GCC_INSTALL_PREFIX", self.compiler.prefix))
@@ -746,7 +892,7 @@ class Llvm(CMakePackage, CudaPackage):
         define = self.define
 
         # unnecessary if we build openmp via LLVM_ENABLE_RUNTIMES
-        if "+cuda ~omp_as_runtime" in self.spec:
+        if "+cuda openmp=project" in self.spec:
             ompdir = "build-bootstrapped-omp"
             prefix_paths = spack.build_environment.get_cmake_prefix_path(self)
             prefix_paths.append(str(spec.prefix))
diff --git a/var/spack/repos/builtin/packages/llvm/sanitizer-ipc_perm_mode.patch b/var/spack/repos/builtin/packages/llvm/sanitizer-ipc_perm_mode.patch
index 8f91703a32..e270f230e7 100644
--- a/var/spack/repos/builtin/packages/llvm/sanitizer-ipc_perm_mode.patch
+++ b/var/spack/repos/builtin/packages/llvm/sanitizer-ipc_perm_mode.patch
@@ -1,9 +1,53 @@
-# ipc_perm.mode is not used and has changed from short to int over architecures
+# ipc_perm.mode is not used and has changed from short to int over architectures
 # and versions. The last change was in glibc-2.31.
 # LLVM upstream decided to not check ipc_perm.mode below glibc-2.31,
 # because it is not actually used in the sanitizer:
-# github.com/llvm/llvm-project/commit/947f9692440836dcb8d88b74b69dd379d85974ce
+# https://reviews.llvm.org/D70662
+#
+# We need the patch to be applicable when="@5:9" and, therefore, cannot
+# fetch it from the upstream repo.
+
 --- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cc
 +++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cc
-@@ -1143,1 +1143,0 @@
--CHECK_SIZE_AND_OFFSET(ipc_perm, mode);
+@@ -1126,8 +1126,9 @@ CHECK_SIZE_AND_OFFSET(ipc_perm, uid);
+ CHECK_SIZE_AND_OFFSET(ipc_perm, gid);
+ CHECK_SIZE_AND_OFFSET(ipc_perm, cuid);
+ CHECK_SIZE_AND_OFFSET(ipc_perm, cgid);
+-#if !defined(__aarch64__) || !SANITIZER_LINUX || __GLIBC_PREREQ (2, 21)
+-/* On aarch64 glibc 2.20 and earlier provided incorrect mode field.  */
++#if !SANITIZER_LINUX || __GLIBC_PREREQ (2, 31)
++/* glibc 2.30 and earlier provided 16-bit mode field instead of 32-bit
++   on many architectures.  */
+ CHECK_SIZE_AND_OFFSET(ipc_perm, mode);
+ #endif
+ 
+--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
++++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
+@@ -203,26 +203,13 @@ namespace __sanitizer {
+     u64 __unused1;
+     u64 __unused2;
+ #elif defined(__sparc__)
+-#if defined(__arch64__)
+     unsigned mode;
+-    unsigned short __pad1;
+-#else
+-    unsigned short __pad1;
+-    unsigned short mode;
+     unsigned short __pad2;
+-#endif
+     unsigned short __seq;
+     unsigned long long __unused1;
+     unsigned long long __unused2;
+-#elif defined(__mips__) || defined(__aarch64__) || defined(__s390x__)
+-    unsigned int mode;
+-    unsigned short __seq;
+-    unsigned short __pad1;
+-    unsigned long __unused1;
+-    unsigned long __unused2;
+ #else
+-    unsigned short mode;
+-    unsigned short __pad1;
++    unsigned int mode;
+     unsigned short __seq;
+     unsigned short __pad2;
+ #if defined(__x86_64__) && !defined(_LP64)
diff --git a/var/spack/repos/builtin/packages/llvm/xray_buffer_queue-cstddef.patch b/var/spack/repos/builtin/packages/llvm/xray_buffer_queue-cstddef.patch
index b5ca841e3e..35e6350445 100644
--- a/var/spack/repos/builtin/packages/llvm/xray_buffer_queue-cstddef.patch
+++ b/var/spack/repos/builtin/packages/llvm/xray_buffer_queue-cstddef.patch
@@ -1,4 +1,12 @@
-# Fix missing std:size_t in 'llvm@4:5' for build with '%clang@7:'
+# The patched file uses size_t, a.k.a. ::size_t (not std::size_t), but does not
+# include <stddef.h> explicitly. Whether or not the header is included
+# implicitly via other headers, depends on the implementation of the standard
+# library. Therefore, we should not apply this patch depending on the compiler
+# version. Strictly speaking, <cstddef> is not guaranteed to provide ::size_t
+# (in contrast to std::size_t). However, it does that in most cases and that is
+# what the upstream developers seem to rely on starting LLVM 6.0.0
+# (see https://reviews.llvm.org/D39175).
+
 --- a/compiler-rt/lib/xray/xray_buffer_queue.h
 +++ b/compiler-rt/lib/xray/xray_buffer_queue.h
 @@ -18,0 +18,1 @@
diff --git a/var/spack/repos/builtin/packages/open3d/package.py b/var/spack/repos/builtin/packages/open3d/package.py
index 497aee7238..60d0ed4eaa 100644
--- a/var/spack/repos/builtin/packages/open3d/package.py
+++ b/var/spack/repos/builtin/packages/open3d/package.py
@@ -24,7 +24,7 @@ class Open3d(CMakePackage, CudaPackage):
     depends_on("cmake@3.19:", type="build")
     # https://github.com/isl-org/Open3D/issues/3762
     # https://github.com/isl-org/Open3D/issues/4570
-    depends_on("llvm@7:+clang+libcxx")
+    depends_on("llvm@7:+clang")
     depends_on("eigen")
     depends_on("flann")
     # https://github.com/isl-org/Open3D/issues/4360
@@ -54,6 +54,9 @@ class Open3d(CMakePackage, CudaPackage):
     conflicts("%gcc@:4")
     conflicts("%clang@:6")
 
+    # LLVM must be built with the C++ library
+    conflicts("^llvm libcxx=none")
+
     def patch(self):
         # Force Python libraries to be installed to self.prefix
         filter_file(