Patch numbering

We've established the habit of numbering patches the following way:

  0-499: All patches that are unconditionally applied
  500-1000: Patches applied under certain conditions (e.g. only on RHEL8)
  1500-1599: Patches for LLVM 15
  1600-1699: Patches for LLVM 16
  1700-1799: Patches for LLVM 17
  ...
  2000-2099: Patches for LLVM 20

The idea behind this is that the last range of patch numbers (e.g. 2000-2099) allow
us to "deprecate" a patch instead of deleting it right away.
Suppose llvm upstream in git is at version 20 and there's a patch living
in some PR that has not been merged yet. You can copy that patch and put it
in a line like:

  Patch2011: upstream.patch

As time goes by, llvm moves on to LLVM 21 and meanwhile the patch has landed.
There's no need for you to remove the "Patch2011:" line. In fact, we encourage you
to not remove it for some time. For compat libraries and compat packages we might
still need this patch and so we're applying it automatically for you in those
situations. Remember that a compat library is always at least one major version
behind the latest packaged LLVM version.

I've restored a patch for an older version of LLVM:

We needed to move the

`0001-Always-build-shared-libs-for-LLD.patch`

from the `0-499` range to the `19xx` (current release) and `20xx`
(snapshots) range. In addition the old version of the patch was restored
with the following command and added to the `18xx` range:

```
$ git show
0656f30e3739d2d371d58f2fad66d634a766e0fe:0001-Always-build-shared-libs-for-LLD.patch
> 0001-18-Always-build-shared-libs-for-LLD.patch
```

This was needed because the `bundle_compat_lib` (RHEL only) build
condition needs the old version of the patch.

0001-18-Always-build-shared-libs-for-LLD.patch

@@ -0,0 +1,29 @@
+From b1c60d7fa322a2d208556087df9e7ef94bfbffb8 Mon Sep 17 00:00:00 2001
+From: Nikita Popov <npopov@redhat.com>
+Date: Wed, 8 May 2024 12:30:36 +0900
+Subject: [PATCH] Always build shared libs for LLD
+
+We don't want to enable BUILD_SHARED_LIBS for the whole build,
+but we do want to build lld libraries.
+---
+ lld/cmake/modules/AddLLD.cmake | 5 ++---
+ 1 file changed, 2 insertions(+), 3 deletions(-)
+
+diff --git a/lld/cmake/modules/AddLLD.cmake b/lld/cmake/modules/AddLLD.cmake
+index 2ee066b41535..270c03f096ac 100644
+--- a/lld/cmake/modules/AddLLD.cmake
++++ b/lld/cmake/modules/AddLLD.cmake
+@@ -7,9 +7,8 @@ macro(add_lld_library name)
+     ""
+     ""
+     ${ARGN})
+-  if(ARG_SHARED)
+-    set(ARG_ENABLE_SHARED SHARED)
+-  endif()
++  # Always build shared libs for LLD.
++  set(ARG_ENABLE_SHARED SHARED)
+   llvm_add_library(${name} ${ARG_ENABLE_SHARED} ${ARG_UNPARSED_ARGUMENTS})
+   set_target_properties(${name} PROPERTIES FOLDER "lld libraries")
+ 
+-- 
+2.44.0

llvm.spec

@@ -206,36 +206,61 @@ Source3001: https://github.com/llvm/llvm-project/releases/download/llvmorg-%{com
 Source1000: version.spec.inc
 %endif
 
+# We've established the habit of numbering patches the following way:
+#
+#   0-499: All patches that are unconditionally applied
+#   500-1000: Patches applied under certain conditions (e.g. only on RHEL8)
+#   1500-1599: Patches for LLVM 15
+#   1600-1699: Patches for LLVM 16
+#   1700-1799: Patches for LLVM 17
+#   ...
+#   2000-2099: Patches for LLVM 20
+#
+# The idea behind this is that the last range of patch numbers (e.g. 2000-2099) allow
+# us to "deprecate" a patch instead of deleting it right away.
+# Suppose llvm upstream in git is at version 20 and there's a patch living
+# in some PR that has not been merged yet. You can copy that patch and put it
+# in a line like:
+#
+#   Patch2011: upstream.patch
+#
+# As time goes by, llvm moves on to LLVM 21 and meanwhile the patch has landed.
+# There's no need for you to remove the "Patch2011:" line. In fact, we encourage you
+# to not remove it for some time. For compat libraries and compat packages we might
+# still need this patch and so we're applying it automatically for you in those
+# situations. Remember that a compat library is always at least one major version
+# behind the latest packaged LLVM version.
+
 #region OpenMP patches
-%if %{maj_ver} < 20
+Patch1900: 0001-openmp-Add-option-to-disable-tsan-tests-111548.patch
-Patch1001: 0001-openmp-Add-option-to-disable-tsan-tests-111548.patch
+Patch1901: 0001-openmp-Use-core_siblings_list-if-physical_package_id.patch
-Patch1002: 0001-openmp-Use-core_siblings_list-if-physical_package_id.patch
-%endif
 #endregion OpenMP patches
 
 #region CLANG patches
-Patch2001: 0001-PATCH-clang-Make-funwind-tables-the-default-on-all-a.patch
+Patch101: 0001-PATCH-clang-Make-funwind-tables-the-default-on-all-a.patch
-Patch2002: 0003-PATCH-clang-Don-t-install-static-libraries.patch
+Patch102: 0003-PATCH-clang-Don-t-install-static-libraries.patch
 #endregion CLANG patches
 
 # Workaround a bug in ORC on ppc64le.
 # More info is available here: https://reviews.llvm.org/D159115#4641826
-Patch2005: 0001-Workaround-a-bug-in-ORC-on-ppc64le.patch
+Patch103: 0001-Workaround-a-bug-in-ORC-on-ppc64le.patch
 
 #region LLD patches
-Patch3002: 0001-Always-build-shared-libs-for-LLD.patch
+Patch1800: 0001-18-Always-build-shared-libs-for-LLD.patch
+Patch1902: 0001-19-Always-build-shared-libs-for-LLD.patch
+Patch2000: 0001-19-Always-build-shared-libs-for-LLD.patch
 #endregion LLD patches
 
 #region RHEL patches
 # All RHEL
 %if %{maj_ver} >= 20
-Patch9001: 0001-20-Remove-myst_parser-dependency-for-RHEL.patch
+Patch500: 0001-20-Remove-myst_parser-dependency-for-RHEL.patch
 %else
-Patch9001: 0001-19-Remove-myst_parser-dependency-for-RHEL.patch
+Patch500: 0001-19-Remove-myst_parser-dependency-for-RHEL.patch
 %endif
 
 # RHEL 8 only
-Patch9002: 0001-Fix-page-size-constant-on-aarch64-and-ppc64le.patch
+Patch501: 0001-Fix-page-size-constant-on-aarch64-and-ppc64le.patch
 #endregion RHEL patches
 
 %if 0%{?rhel} == 8
@@ -724,6 +749,14 @@ The package contains the LLDB Python module.
 %if %{with bundle_compat_lib}
 %{gpgverify} --keyring='%{SOURCE6}' --signature='%{SOURCE3001}' --data='%{SOURCE3000}'
 %setup -T -q -b 3000 -n llvm-project-%{compat_ver}.src
+
+# Apply all patches with number < 500 (unconditionally)
+# See https://rpm-software-management.github.io/rpm/manual/autosetup.html
+%autopatch -M499 -p1
+
+# automatically apply patches based on LLVM version
+%autopatch -m%{compat_maj_ver}00 -M%{compat_maj_ver}99 -p1
+
 %endif
 
 # -T     : Do Not Perform Default Archive Unpacking (without this, the <n>th source would be unpacked twice)
@@ -733,15 +766,18 @@ The package contains the LLDB Python module.
 # see http://ftp.rpm.org/max-rpm/s1-rpm-inside-macros.html
 %autosetup -N -T -b 0 -n %{src_tarball_dir}
 
-# Apply all patches with number <= 9000
+# Apply all patches with number < 500 (unconditionally)
 # See https://rpm-software-management.github.io/rpm/manual/autosetup.html
-%autopatch -M9000 -p1
+%autopatch -M499 -p1
+
+# automatically apply patches based on LLVM version
+%autopatch -m%{maj_ver}00 -M%{maj_ver}99 -p1
 
 %if %{defined rhel}
-%patch -p1 -P9001
+%patch -p1 -P500
 
 %if %{rhel} == 8
-%patch -p1 -P9002
+%patch -p1 -P501
 %endif
 %endif
 
@@ -1374,7 +1410,7 @@ function reset_test_opts()
 
     # See https://llvm.org/docs/CommandGuide/lit.html#general-options
     export LIT_OPTS="-vv --time-tests"
-    
+
     # Set to mark tests as expected to fail.
     # See https://llvm.org/docs/CommandGuide/lit.html#cmdoption-lit-xfail
     unset LIT_XFAIL