diff --git a/doc/release-notes/rl-2511.section.md b/doc/release-notes/rl-2511.section.md
index a98d2f468196..1d8f32f41d45 100644
--- a/doc/release-notes/rl-2511.section.md
+++ b/doc/release-notes/rl-2511.section.md
@@ -26,6 +26,8 @@
 
 - GCC 9, 10, 11, and 12 have been removed, as they have reached end‐of‐life upstream and are no longer supported.
 
+- LLVM 12 has been removed, as it has reached end‐of‐life upstream and is no longer supported.
+
 - GHCJS 8.10, exposed via `haskell.compiler.ghcjs` and `haskell.compiler.ghcjs810`, has been removed. Downstream users should migrate their projects to the new JavaScript backend of GHC proper which can be used via `pkgsCross.ghcjs` from Nixpkgs. Haskell packaging code, like `haskellPackages.mkDerivation`, `ghcWithPackages` and `hoogleWithPackages`, also no longer supports GHCJS.
 
 - GHC 8.6, 8.10, 9.0, 9.2, and their package sets have been removed.
diff --git a/pkgs/development/compilers/llvm/12/compiler-rt/armv7l.patch b/pkgs/development/compilers/llvm/12/compiler-rt/armv7l.patch
deleted file mode 100644
index 120cfe6feb2a..000000000000
--- a/pkgs/development/compilers/llvm/12/compiler-rt/armv7l.patch
+++ /dev/null
@@ -1,32 +0,0 @@
-diff -ur compiler-rt-10.0.0.src/cmake/builtin-config-ix.cmake compiler-rt-10.0.0.src-patched/cmake/builtin-config-ix.cmake
---- compiler-rt-10.0.0.src/cmake/builtin-config-ix.cmake	2020-03-24 00:01:02.000000000 +0900
-+++ compiler-rt-10.0.0.src-patched/cmake/builtin-config-ix.cmake	2020-05-10 03:42:00.883450706 +0900
-@@ -24,7 +24,7 @@
- 
- 
- set(ARM64 aarch64)
--set(ARM32 arm armhf armv6m armv7m armv7em armv7 armv7s armv7k)
-+set(ARM32 arm armhf armv6m armv7m armv7em armv7 armv7s armv7k armv7l)
- set(HEXAGON hexagon)
- set(X86 i386)
- set(X86_64 x86_64)
-diff -ur compiler-rt-10.0.0.src/lib/builtins/CMakeLists.txt compiler-rt-10.0.0.src-patched/lib/builtins/CMakeLists.txt
---- compiler-rt-10.0.0.src/lib/builtins/CMakeLists.txt	2020-03-24 00:01:02.000000000 +0900
-+++ compiler-rt-10.0.0.src-patched/lib/builtins/CMakeLists.txt	2020-05-10 03:44:49.468579650 +0900
-@@ -474,6 +474,7 @@
- set(armv7_SOURCES ${arm_SOURCES})
- set(armv7s_SOURCES ${arm_SOURCES})
- set(armv7k_SOURCES ${arm_SOURCES})
-+set(armv7l_SOURCES ${arm_SOURCES})
- set(arm64_SOURCES ${aarch64_SOURCES})
- 
- # macho_embedded archs
-@@ -595,7 +596,7 @@
-   foreach (arch ${BUILTIN_SUPPORTED_ARCH})
-     if (CAN_TARGET_${arch})
-       # For ARM archs, exclude any VFP builtins if VFP is not supported
--      if (${arch} MATCHES "^(arm|armhf|armv7|armv7s|armv7k|armv7m|armv7em)$")
-+      if (${arch} MATCHES "^(arm|armhf|armv7|armv7s|armv7k|armv7l|armv7m|armv7em)$")
-         string(REPLACE ";" " " _TARGET_${arch}_CFLAGS "${TARGET_${arch}_CFLAGS}")
-         check_compile_definition(__VFP_FP__ "${CMAKE_C_FLAGS} ${_TARGET_${arch}_CFLAGS}" COMPILER_RT_HAS_${arch}_VFP)
-         if(NOT COMPILER_RT_HAS_${arch}_VFP)
diff --git a/pkgs/development/compilers/llvm/12/compiler-rt/codesign.patch b/pkgs/development/compilers/llvm/12/compiler-rt/codesign.patch
deleted file mode 100644
index 3cc12b94b200..000000000000
--- a/pkgs/development/compilers/llvm/12/compiler-rt/codesign.patch
+++ /dev/null
@@ -1,33 +0,0 @@
-From 3dec5f3475a26aeb4678627795c4b67c6b7b4785 Mon Sep 17 00:00:00 2001
-From: Will Dietz <w@wdtz.org>
-Date: Tue, 19 Sep 2017 13:13:06 -0500
-Subject: [PATCH] remove codesign use on Apple, disable ios sim testing that
- needs it
-
----
- cmake/Modules/AddCompilerRT.cmake |  8 ------
- test/asan/CMakeLists.txt          | 52 ---------------------------------------
- test/tsan/CMakeLists.txt          | 47 -----------------------------------
- 3 files changed, 107 deletions(-)
-
-diff --git a/cmake/Modules/AddCompilerRT.cmake b/cmake/Modules/AddCompilerRT.cmake
-index bc5fb9ff7..b64eb4246 100644
---- a/cmake/Modules/AddCompilerRT.cmake
-+++ b/cmake/Modules/AddCompilerRT.cmake
-@@ -210,14 +210,6 @@ function(add_compiler_rt_runtime name type)
-         set_target_properties(${libname} PROPERTIES IMPORT_PREFIX "")
-         set_target_properties(${libname} PROPERTIES IMPORT_SUFFIX ".lib")
-       endif()
--      if(APPLE)
--        # Ad-hoc sign the dylibs
--        add_custom_command(TARGET ${libname}
--          POST_BUILD  
--          COMMAND codesign --sign - $<TARGET_FILE:${libname}>
--          WORKING_DIRECTORY ${COMPILER_RT_LIBRARY_OUTPUT_DIR}
--        )
--      endif()
-     endif()
-     install(TARGETS ${libname}
-       ARCHIVE DESTINATION ${COMPILER_RT_LIBRARY_INSTALL_DIR}
-2.14.1
-
diff --git a/pkgs/development/compilers/llvm/12/libunwind/gnu-install-dirs.patch b/pkgs/development/compilers/llvm/12/libunwind/gnu-install-dirs.patch
deleted file mode 100644
index a791d6c43231..000000000000
--- a/pkgs/development/compilers/llvm/12/libunwind/gnu-install-dirs.patch
+++ /dev/null
@@ -1,34 +0,0 @@
-diff --git a/CMakeLists.txt b/CMakeLists.txt
-index 48cb8e004e08..fec8144fb95a 100644
---- a/CMakeLists.txt
-+++ b/CMakeLists.txt
-@@ -23,6 +23,8 @@ set(LIBUNWIND_LIBCXX_PATH "${CMAKE_CURRENT_LIST_DIR}/../libcxx" CACHE PATH
- if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR OR LIBUNWIND_STANDALONE_BUILD)
-   project(libunwind LANGUAGES C CXX ASM)
- 
-+  include(GNUInstallDirs)
-+
-   set(PACKAGE_NAME libunwind)
-   set(PACKAGE_VERSION 12.0.0)
-   set(PACKAGE_STRING "${PACKAGE_NAME} ${PACKAGE_VERSION}")
-@@ -115,17 +117,17 @@ set(CMAKE_MODULE_PATH
- 
- if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
-   set(LIBUNWIND_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/${LLVM_DEFAULT_TARGET_TRIPLE}/c++)
--  set(LIBUNWIND_INSTALL_LIBRARY_DIR lib${LLVM_LIBDIR_SUFFIX}/${LLVM_DEFAULT_TARGET_TRIPLE}/c++)
-+  set(LIBUNWIND_INSTALL_LIBRARY_DIR ${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX}/${LLVM_DEFAULT_TARGET_TRIPLE}/c++)
-   if(LIBCXX_LIBDIR_SUBDIR)
-     string(APPEND LIBUNWIND_LIBRARY_DIR /${LIBUNWIND_LIBDIR_SUBDIR})
-     string(APPEND LIBUNWIND_INSTALL_LIBRARY_DIR /${LIBUNWIND_LIBDIR_SUBDIR})
-   endif()
- elseif(LLVM_LIBRARY_OUTPUT_INTDIR)
-   set(LIBUNWIND_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
--  set(LIBUNWIND_INSTALL_LIBRARY_DIR lib${LIBUNWIND_LIBDIR_SUFFIX})
-+  set(LIBUNWIND_INSTALL_LIBRARY_DIR ${CMAKE_INSTALL_LIBDIR}${LIBUNWIND_LIBDIR_SUFFIX})
- else()
-   set(LIBUNWIND_LIBRARY_DIR ${CMAKE_BINARY_DIR}/lib${LIBUNWIND_LIBDIR_SUFFIX})
--  set(LIBUNWIND_INSTALL_LIBRARY_DIR lib${LIBUNWIND_LIBDIR_SUFFIX})
-+  set(LIBUNWIND_INSTALL_LIBRARY_DIR ${CMAKE_INSTALL_LIBDIR}${LIBUNWIND_LIBDIR_SUFFIX})
- endif()
- 
- set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LIBUNWIND_LIBRARY_DIR})
diff --git a/pkgs/development/compilers/llvm/12/lldb/gnu-install-dirs.patch b/pkgs/development/compilers/llvm/12/lldb/gnu-install-dirs.patch
deleted file mode 100644
index 9a4d2b272acb..000000000000
--- a/pkgs/development/compilers/llvm/12/lldb/gnu-install-dirs.patch
+++ /dev/null
@@ -1,110 +0,0 @@
-diff --git a/CMakeLists.txt b/CMakeLists.txt
-index b5633e21c56a..f2f1035e9238 100644
---- a/CMakeLists.txt
-+++ b/CMakeLists.txt
-@@ -10,6 +10,8 @@ set(CMAKE_MODULE_PATH
- # If we are not building as part of LLVM, build LLDB as a standalone project,
- # using LLVM as an external library.
- if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-+  include(GNUInstallDirs)
-+
-   project(lldb)
-   include(LLDBStandalone)
- 
-diff --git a/cmake/modules/AddLLDB.cmake b/cmake/modules/AddLLDB.cmake
-index 4ed5c647c5d2..89f96e710d55 100644
---- a/cmake/modules/AddLLDB.cmake
-+++ b/cmake/modules/AddLLDB.cmake
-@@ -107,13 +107,13 @@ function(add_lldb_library name)
-   endif()
- 
-   if(PARAM_SHARED)
--    set(install_dest lib${LLVM_LIBDIR_SUFFIX})
-+    set(install_dest ${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX})
-     if(PARAM_INSTALL_PREFIX)
-       set(install_dest ${PARAM_INSTALL_PREFIX})
-     endif()
-     # RUNTIME is relevant for DLL platforms, FRAMEWORK for macOS
-     install(TARGETS ${name} COMPONENT ${name}
--      RUNTIME DESTINATION bin
-+      RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
-       LIBRARY DESTINATION ${install_dest}
-       ARCHIVE DESTINATION ${install_dest}
-       FRAMEWORK DESTINATION ${install_dest})
-diff --git a/cmake/modules/LLDBConfig.cmake b/cmake/modules/LLDBConfig.cmake
-index 2fdf1502d055..37364341ff8b 100644
---- a/cmake/modules/LLDBConfig.cmake
-+++ b/cmake/modules/LLDBConfig.cmake
-@@ -225,7 +225,7 @@ include_directories(BEFORE
- if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
-   install(DIRECTORY include/
-     COMPONENT lldb-headers
--    DESTINATION include
-+    DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
-     FILES_MATCHING
-     PATTERN "*.h"
-     PATTERN ".cmake" EXCLUDE
-@@ -233,7 +233,7 @@ if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
- 
-   install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/include/
-     COMPONENT lldb-headers
--    DESTINATION include
-+    DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
-     FILES_MATCHING
-     PATTERN "*.h"
-     PATTERN ".cmake" EXCLUDE
-diff --git a/tools/intel-features/CMakeLists.txt b/tools/intel-features/CMakeLists.txt
-index 734167e51bc5..f95761b5df58 100644
---- a/tools/intel-features/CMakeLists.txt
-+++ b/tools/intel-features/CMakeLists.txt
-@@ -65,4 +65,4 @@ if (LLDB_ENABLE_PYTHON AND LLDB_BUILD_INTEL_PT)
- endif()
- 
- install(TARGETS lldbIntelFeatures
--  LIBRARY DESTINATION lib${LLVM_LIBDIR_SUFFIX})
-+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX})
-diff --git a/cmake/modules/LLDBStandalone.cmake b/cmake/modules/LLDBStandalone.cmake
-index 752113b..010f187 100644
---- a/cmake/modules/LLDBStandalone.cmake
-+++ b/cmake/modules/LLDBStandalone.cmake
-@@ -62,7 +62,7 @@ endif()
-
- # They are used as destination of target generators.
- set(LLVM_RUNTIME_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin)
--set(LLVM_LIBRARY_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib${LLVM_LIBDIR_SUFFIX})
-+set(LLVM_LIBRARY_OUTPUT_INTDIR ${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX})
- if(WIN32 OR CYGWIN)
-   # DLL platform -- put DLLs into bin.
-   set(LLVM_SHLIB_OUTPUT_INTDIR ${LLVM_RUNTIME_OUTPUT_INTDIR})
-diff --git a/CMakeLists.txt b/CMakeLists.txt
-index b5633e2..86e4738 100644
---- a/CMakeLists.txt
-+++ b/CMakeLists.txt
-@@ -79,7 +79,7 @@ if (LLDB_ENABLE_PYTHON)
-   if(LLDB_BUILD_FRAMEWORK)
-     set(lldb_python_target_dir "${LLDB_FRAMEWORK_ABSOLUTE_BUILD_DIR}/LLDB.framework/Resources/Python/lldb")
-   else()
--    set(lldb_python_target_dir "${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/${LLDB_PYTHON_RELATIVE_PATH}/lldb")
-+    set(lldb_python_target_dir "${CMAKE_INSTALL_LIBDIR}/../${LLDB_PYTHON_RELATIVE_PATH}/lldb")
-   endif()
-   get_target_property(lldb_python_bindings_dir swig_wrapper_python BINARY_DIR)
-   finish_swig_python("lldb-python" "${lldb_python_bindings_dir}" "${lldb_python_target_dir}")
-diff --git a/source/API/CMakeLists.txt b/source/API/CMakeLists.txt
-index b5633e2..86e4738 100644
---- a/source/API/CMakeLists.txt	2024-05-30 19:08:14.241656491 -0700
-+++ b/source/API/CMakeLists.txt	2024-05-30 19:08:48.218219667 -0700
-@@ -113,14 +113,6 @@
-   ${option_install_prefix}
- )
- 
--# lib/pythonX.Y/dist-packages/lldb/_lldb.so is a symlink to lib/liblldb.so,
--# which depends on lib/libLLVM*.so (BUILD_SHARED_LIBS) or lib/libLLVM-10git.so
--# (LLVM_LINK_LLVM_DYLIB). Add an additional rpath $ORIGIN/../../../../lib so
--# that _lldb.so can be loaded from Python.
--if(LLDB_ENABLE_PYTHON AND (BUILD_SHARED_LIBS OR LLVM_LINK_LLVM_DYLIB) AND UNIX AND NOT APPLE)
--  set_property(TARGET liblldb APPEND PROPERTY INSTALL_RPATH "\$ORIGIN/../../../../lib${LLVM_LIBDIR_SUFFIX}")
--endif()
--
- if(Python3_RPATH)
-   set_property(TARGET liblldb APPEND PROPERTY INSTALL_RPATH "${Python3_RPATH}")
-   set_property(TARGET liblldb APPEND PROPERTY BUILD_RPATH   "${Python3_RPATH}")
diff --git a/pkgs/development/compilers/llvm/12/llvm/fix-llvm-issue-49955.patch b/pkgs/development/compilers/llvm/12/llvm/fix-llvm-issue-49955.patch
deleted file mode 100644
index b515583a0c42..000000000000
--- a/pkgs/development/compilers/llvm/12/llvm/fix-llvm-issue-49955.patch
+++ /dev/null
@@ -1,13 +0,0 @@
-diff --git a/lib/CodeGen/AsmPrinter/CMakeLists.txt b/lib/CodeGen/AsmPrinter/CMakeLists.txt
-index eb924282..c77c140b 100644
---- a/lib/CodeGen/AsmPrinter/CMakeLists.txt
-+++ b/lib/CodeGen/AsmPrinter/CMakeLists.txt
-@@ -44,3 +44,8 @@ add_llvm_component_library(LLVMAsmPrinter
-   Support
-   Target
-   )
-+
-+if (CMAKE_COMPILER_IS_GNUCXX)
-+  set_source_files_properties(DwarfCompileUnit.cpp PROPERTIES
-+                              COMPILE_FLAGS -fno-strict-aliasing)
-+endif()
diff --git a/pkgs/development/compilers/llvm/12/llvm/gnu-install-dirs-polly.patch b/pkgs/development/compilers/llvm/12/llvm/gnu-install-dirs-polly.patch
deleted file mode 100644
index 68f3c45396f6..000000000000
--- a/pkgs/development/compilers/llvm/12/llvm/gnu-install-dirs-polly.patch
+++ /dev/null
@@ -1,105 +0,0 @@
-diff --git a/tools/polly/CMakeLists.txt b/tools/polly/CMakeLists.txt
-index ca7c04c565bb..6ed5db5dd4f8 100644
---- a/tools/polly/CMakeLists.txt
-+++ b/tools/polly/CMakeLists.txt
-@@ -2,7 +2,11 @@
- if (NOT DEFINED LLVM_MAIN_SRC_DIR)
-   project(Polly)
-   cmake_minimum_required(VERSION 3.13.4)
-+endif()
-+
-+include(GNUInstallDirs)
- 
-+if (NOT DEFINED LLVM_MAIN_SRC_DIR)
-   # Where is LLVM installed?
-   find_package(LLVM CONFIG REQUIRED)
-   set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${LLVM_CMAKE_DIR})
-@@ -122,13 +126,13 @@ include_directories(
- 
- if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
-   install(DIRECTORY include/
--    DESTINATION include
-+    DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
-     FILES_MATCHING
-     PATTERN "*.h"
-     )
- 
-   install(DIRECTORY ${POLLY_BINARY_DIR}/include/
--    DESTINATION include
-+    DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
-     FILES_MATCHING
-     PATTERN "*.h"
-     PATTERN "CMakeFiles" EXCLUDE
-diff --git a/tools/polly/cmake/CMakeLists.txt b/tools/polly/cmake/CMakeLists.txt
-index 7cc129ba2e90..137be25e4b80 100644
---- a/tools/polly/cmake/CMakeLists.txt
-+++ b/tools/polly/cmake/CMakeLists.txt
-@@ -79,18 +79,18 @@ file(GENERATE
- 
- # Generate PollyConfig.cmake for the install tree.
- unset(POLLY_EXPORTS)
--set(POLLY_INSTALL_PREFIX "${CMAKE_INSTALL_PREFIX}")
-+set(POLLY_INSTALL_PREFIX "")
- set(POLLY_CONFIG_LLVM_CMAKE_DIR "${LLVM_BINARY_DIR}/${LLVM_INSTALL_PACKAGE_DIR}")
--set(POLLY_CONFIG_CMAKE_DIR "${POLLY_INSTALL_PREFIX}/${POLLY_INSTALL_PACKAGE_DIR}")
--set(POLLY_CONFIG_LIBRARY_DIRS "${POLLY_INSTALL_PREFIX}/lib${LLVM_LIBDIR_SUFFIX}")
-+set(POLLY_CONFIG_CMAKE_DIR "${POLLY_INSTALL_PREFIX}${CMAKE_INSTALL_PREFIX}/${POLLY_INSTALL_PACKAGE_DIR}")
-+set(POLLY_CONFIG_LIBRARY_DIRS "${POLLY_INSTALL_PREFIX}${CMAKE_INSTALL_FULL_LIBDIR}${LLVM_LIBDIR_SUFFIX}")
- if (POLLY_BUNDLED_ISL)
-   set(POLLY_CONFIG_INCLUDE_DIRS
--    "${POLLY_INSTALL_PREFIX}/include"
--    "${POLLY_INSTALL_PREFIX}/include/polly"
-+    "${POLLY_INSTALL_PREFIX}${CMAKE_INSTALL_FULL_LIBDIR}"
-+    "${POLLY_INSTALL_PREFIX}${CMAKE_INSTALL_FULL_LIBDIR}/polly"
-     )
- else()
-   set(POLLY_CONFIG_INCLUDE_DIRS
--    "${POLLY_INSTALL_PREFIX}/include"
-+    "${POLLY_INSTALL_PREFIX}${CMAKE_INSTALL_FULL_INCLUDEDIR}"
-     ${ISL_INCLUDE_DIRS}
-     )
- endif()
-@@ -100,12 +100,12 @@ endif()
- foreach(tgt IN LISTS POLLY_CONFIG_EXPORTED_TARGETS)
-   get_target_property(tgt_type ${tgt} TYPE)
-   if (tgt_type STREQUAL "EXECUTABLE")
--    set(tgt_prefix "bin/")
-+    set(tgt_prefix "${CMAKE_INSTALL_BINDIR}/")
-   else()
--    set(tgt_prefix "lib/")
-+    set(tgt_prefix "${CMAKE_INSTALL_LIBDIR}/")
-   endif()
- 
--  set(tgt_path "${CMAKE_INSTALL_PREFIX}/${tgt_prefix}$<TARGET_FILE_NAME:${tgt}>")
-+  set(tgt_path "${tgt_prefix}$<TARGET_FILE_NAME:${tgt}>")
-   file(RELATIVE_PATH tgt_path ${POLLY_CONFIG_CMAKE_DIR} ${tgt_path})
- 
-   if (NOT tgt_type STREQUAL "INTERFACE_LIBRARY")
-diff --git a/tools/polly/cmake/polly_macros.cmake b/tools/polly/cmake/polly_macros.cmake
-index 518a09b45a42..bd9d6f5542ad 100644
---- a/tools/polly/cmake/polly_macros.cmake
-+++ b/tools/polly/cmake/polly_macros.cmake
-@@ -44,8 +44,8 @@ macro(add_polly_library name)
-   if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY OR ${name} STREQUAL "LLVMPolly")
-     install(TARGETS ${name}
-       EXPORT LLVMExports
--      LIBRARY DESTINATION lib${LLVM_LIBDIR_SUFFIX}
--      ARCHIVE DESTINATION lib${LLVM_LIBDIR_SUFFIX})
-+	  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX}
-+      ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX})
-   endif()
-   set_property(GLOBAL APPEND PROPERTY LLVM_EXPORTS ${name})
- endmacro(add_polly_library)
-diff --git a/tools/polly/lib/External/CMakeLists.txt b/tools/polly/lib/External/CMakeLists.txt
-index 8991094d92c7..178d8ad606bb 100644
---- a/tools/polly/lib/External/CMakeLists.txt
-+++ b/tools/polly/lib/External/CMakeLists.txt
-@@ -275,7 +275,7 @@ if (POLLY_BUNDLED_ISL)
-     install(DIRECTORY
-       ${ISL_SOURCE_DIR}/include/
-       ${ISL_BINARY_DIR}/include/
--      DESTINATION include/polly
-+      DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/polly
-       FILES_MATCHING
-       PATTERN "*.h"
-       PATTERN "CMakeFiles" EXCLUDE
diff --git a/pkgs/development/compilers/llvm/12/llvm/gnu-install-dirs.patch b/pkgs/development/compilers/llvm/12/llvm/gnu-install-dirs.patch
deleted file mode 100644
index da8dc1445171..000000000000
--- a/pkgs/development/compilers/llvm/12/llvm/gnu-install-dirs.patch
+++ /dev/null
@@ -1,417 +0,0 @@
-diff --git a/CMakeLists.txt b/CMakeLists.txt
-index 277d0fe54d7b..af69c8be8745 100644
---- a/CMakeLists.txt
-+++ b/CMakeLists.txt
-@@ -256,15 +256,21 @@ if (CMAKE_BUILD_TYPE AND
-   message(FATAL_ERROR "Invalid value for CMAKE_BUILD_TYPE: ${CMAKE_BUILD_TYPE}")
- endif()
- 
-+include(GNUInstallDirs)
-+
- set(LLVM_LIBDIR_SUFFIX "" CACHE STRING "Define suffix of library directory name (32/64)" )
- 
--set(LLVM_TOOLS_INSTALL_DIR "bin" CACHE STRING "Path for binary subdirectory (defaults to 'bin')")
-+set(LLVM_TOOLS_INSTALL_DIR "${CMAKE_INSTALL_BINDIR}" CACHE STRING
-+    "Path for binary subdirectory (defaults to 'bin')")
- mark_as_advanced(LLVM_TOOLS_INSTALL_DIR)
- 
- set(LLVM_UTILS_INSTALL_DIR "${LLVM_TOOLS_INSTALL_DIR}" CACHE STRING
-     "Path to install LLVM utilities (enabled by LLVM_INSTALL_UTILS=ON) (defaults to LLVM_TOOLS_INSTALL_DIR)")
- mark_as_advanced(LLVM_UTILS_INSTALL_DIR)
- 
-+set(LLVM_INSTALL_CMAKE_DIR "${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX}/cmake/llvm" CACHE STRING
-+	"Path for CMake subdirectory (defaults to lib/cmake/llvm)" )
-+
- # They are used as destination of target generators.
- set(LLVM_RUNTIME_OUTPUT_INTDIR ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin)
- set(LLVM_LIBRARY_OUTPUT_INTDIR ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib${LLVM_LIBDIR_SUFFIX})
-@@ -567,9 +573,9 @@ option (LLVM_ENABLE_SPHINX "Use Sphinx to generate llvm documentation." OFF)
- option (LLVM_ENABLE_OCAMLDOC "Build OCaml bindings documentation." ON)
- option (LLVM_ENABLE_BINDINGS "Build bindings." ON)
- 
--set(LLVM_INSTALL_DOXYGEN_HTML_DIR "share/doc/llvm/doxygen-html"
-+set(LLVM_INSTALL_DOXYGEN_HTML_DIR "${CMAKE_INSTALL_DOCDIR}/${project}/doxygen-html"
-     CACHE STRING "Doxygen-generated HTML documentation install directory")
--set(LLVM_INSTALL_OCAMLDOC_HTML_DIR "share/doc/llvm/ocaml-html"
-+set(LLVM_INSTALL_OCAMLDOC_HTML_DIR "${CMAKE_INSTALL_DOCDIR}/${project}/ocaml-html"
-     CACHE STRING "OCamldoc-generated HTML documentation install directory")
- 
- option (LLVM_BUILD_EXTERNAL_COMPILER_RT
-@@ -1027,7 +1033,7 @@ endif()
- 
- if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
-   install(DIRECTORY include/llvm include/llvm-c
--    DESTINATION include
-+    DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
-     COMPONENT llvm-headers
-     FILES_MATCHING
-     PATTERN "*.def"
-@@ -1038,7 +1044,7 @@ if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
-     )
- 
-   install(DIRECTORY ${LLVM_INCLUDE_DIR}/llvm ${LLVM_INCLUDE_DIR}/llvm-c
--    DESTINATION include
-+    DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
-     COMPONENT llvm-headers
-     FILES_MATCHING
-     PATTERN "*.def"
-@@ -1052,13 +1058,13 @@ if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
- 
-   if (LLVM_INSTALL_MODULEMAPS)
-     install(DIRECTORY include/llvm include/llvm-c
--            DESTINATION include
-+            DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
-             COMPONENT llvm-headers
-             FILES_MATCHING
-             PATTERN "module.modulemap"
-             )
-     install(FILES include/llvm/module.install.modulemap
--            DESTINATION include/llvm
-+            DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/llvm
-             COMPONENT llvm-headers
-             RENAME "module.extern.modulemap"
-             )
-diff --git a/cmake/modules/AddLLVM.cmake b/cmake/modules/AddLLVM.cmake
-index 97c9980c7de3..409e8b615f75 100644
---- a/cmake/modules/AddLLVM.cmake
-+++ b/cmake/modules/AddLLVM.cmake
-@@ -804,9 +804,9 @@ macro(add_llvm_library name)
- 
-       install(TARGETS ${name}
-               ${export_to_llvmexports}
--              LIBRARY DESTINATION lib${LLVM_LIBDIR_SUFFIX} COMPONENT ${name}
--              ARCHIVE DESTINATION lib${LLVM_LIBDIR_SUFFIX} COMPONENT ${name}
--              RUNTIME DESTINATION bin COMPONENT ${name})
-+              LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX} COMPONENT ${name}
-+              ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX} COMPONENT ${name}
-+              RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR} COMPONENT ${name})
- 
-       if (NOT LLVM_ENABLE_IDE)
-         add_llvm_install_targets(install-${name}
-@@ -1022,7 +1022,7 @@ function(process_llvm_pass_plugins)
-           "set(LLVM_STATIC_EXTENSIONS ${LLVM_STATIC_EXTENSIONS})")
-       install(FILES
-           ${llvm_cmake_builddir}/LLVMConfigExtensions.cmake
--          DESTINATION ${LLVM_INSTALL_PACKAGE_DIR}
-+          DESTINATION ${LLVM_INSTALL_CMAKE_DIR}
-           COMPONENT cmake-exports)
- 
-       set(ExtensionDef "${LLVM_BINARY_DIR}/include/llvm/Support/Extension.def")
-@@ -1242,7 +1242,7 @@ macro(add_llvm_example name)
-   endif()
-   add_llvm_executable(${name} ${ARGN})
-   if( LLVM_BUILD_EXAMPLES )
--    install(TARGETS ${name} RUNTIME DESTINATION examples)
-+    install(TARGETS ${name} RUNTIME DESTINATION ${CMAKE_INSTALL_DOCDIR}/examples)
-   endif()
-   set_target_properties(${name} PROPERTIES FOLDER "Examples")
- endmacro(add_llvm_example name)
-@@ -1854,7 +1854,7 @@ function(llvm_install_library_symlink name dest type)
-   set(full_name ${CMAKE_${type}_LIBRARY_PREFIX}${name}${CMAKE_${type}_LIBRARY_SUFFIX})
-   set(full_dest ${CMAKE_${type}_LIBRARY_PREFIX}${dest}${CMAKE_${type}_LIBRARY_SUFFIX})
- 
--  set(output_dir lib${LLVM_LIBDIR_SUFFIX})
-+  set(output_dir ${CMAKE_INSTALL_FULL_LIBDIR}${LLVM_LIBDIR_SUFFIX})
-   if(WIN32 AND "${type}" STREQUAL "SHARED")
-     set(output_dir bin)
-   endif()
-@@ -1871,7 +1871,7 @@ function(llvm_install_library_symlink name dest type)
-   endif()
- endfunction()
- 
--function(llvm_install_symlink name dest)
-+function(llvm_install_symlink name dest output_dir)
-   cmake_parse_arguments(ARG "ALWAYS_GENERATE" "COMPONENT" "" ${ARGN})
-   foreach(path ${CMAKE_MODULE_PATH})
-     if(EXISTS ${path}/LLVMInstallSymlink.cmake)
-@@ -1894,7 +1894,7 @@ function(llvm_install_symlink name dest)
-   set(full_dest ${dest}${CMAKE_EXECUTABLE_SUFFIX})
- 
-   install(SCRIPT ${INSTALL_SYMLINK}
--          CODE "install_symlink(${full_name} ${full_dest} ${LLVM_TOOLS_INSTALL_DIR})"
-+          CODE "install_symlink(${full_name} ${full_dest} ${output_dir})"
-           COMPONENT ${component})
- 
-   if (NOT LLVM_ENABLE_IDE AND NOT ARG_ALWAYS_GENERATE)
-@@ -1977,7 +1977,8 @@ function(add_llvm_tool_symlink link_name target)
-     endif()
- 
-     if ((TOOL_IS_TOOLCHAIN OR NOT LLVM_INSTALL_TOOLCHAIN_ONLY) AND LLVM_BUILD_TOOLS)
--      llvm_install_symlink(${link_name} ${target})
-+      GNUInstallDirs_get_absolute_install_dir(output_dir LLVM_TOOLS_INSTALL_DIR)
-+      llvm_install_symlink(${link_name} ${target} ${output_dir})
-     endif()
-   endif()
- endfunction()
-@@ -2100,9 +2101,9 @@ function(llvm_setup_rpath name)
- 
-   if (APPLE)
-     set(_install_name_dir INSTALL_NAME_DIR "@rpath")
--    set(_install_rpath "@loader_path/../lib${LLVM_LIBDIR_SUFFIX}" ${extra_libdir})
-+    set(_install_rpath "@loader_path/../${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX}" ${extra_libdir})
-   elseif(UNIX)
--    set(_install_rpath "\$ORIGIN/../lib${LLVM_LIBDIR_SUFFIX}" ${extra_libdir})
-+    set(_install_rpath "\$ORIGIN/../${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX}" ${extra_libdir})
-     if(${CMAKE_SYSTEM_NAME} MATCHES "(FreeBSD|DragonFly)")
-       set_property(TARGET ${name} APPEND_STRING PROPERTY
-                    LINK_FLAGS " -Wl,-z,origin ")
-diff --git a/cmake/modules/AddOCaml.cmake b/cmake/modules/AddOCaml.cmake
-index 554046b20edf..4d1ad980641e 100644
---- a/cmake/modules/AddOCaml.cmake
-+++ b/cmake/modules/AddOCaml.cmake
-@@ -144,9 +144,9 @@ function(add_ocaml_library name)
-   endforeach()
- 
-   if( APPLE )
--    set(ocaml_rpath "@executable_path/../../../lib${LLVM_LIBDIR_SUFFIX}")
-+    set(ocaml_rpath "@executable_path/../../../${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX}")
-   elseif( UNIX )
--    set(ocaml_rpath "\\$ORIGIN/../../../lib${LLVM_LIBDIR_SUFFIX}")
-+    set(ocaml_rpath "\\$ORIGIN/../../../${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX}")
-   endif()
-   list(APPEND ocaml_flags "-ldopt" "-Wl,-rpath,${ocaml_rpath}")
- 
-diff --git a/cmake/modules/AddSphinxTarget.cmake b/cmake/modules/AddSphinxTarget.cmake
-index e80c3b5c1cac..482f6d715ef5 100644
---- a/cmake/modules/AddSphinxTarget.cmake
-+++ b/cmake/modules/AddSphinxTarget.cmake
-@@ -90,7 +90,7 @@ function (add_sphinx_target builder project)
-         endif()
-       elseif (builder STREQUAL html)
-         string(TOUPPER "${project}" project_upper)
--        set(${project_upper}_INSTALL_SPHINX_HTML_DIR "share/doc/${project}/html"
-+        set(${project_upper}_INSTALL_SPHINX_HTML_DIR "${CMAKE_INSTALL_DOCDIR}/${project}/html"
-             CACHE STRING "HTML documentation install directory for ${project}")
- 
-         # '/.' indicates: copy the contents of the directory directly into
-diff --git a/cmake/modules/CMakeLists.txt b/cmake/modules/CMakeLists.txt
-index 505dc9a29d70..36e6c63af3f4 100644
---- a/cmake/modules/CMakeLists.txt
-+++ b/cmake/modules/CMakeLists.txt
-@@ -1,4 +1,4 @@
--set(LLVM_INSTALL_PACKAGE_DIR lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm)
-+set(LLVM_INSTALL_PACKAGE_DIR ${LLVM_INSTALL_CMAKE_DIR} CACHE STRING "Path for CMake subdirectory (defaults to 'cmake/llvm')")
- set(llvm_cmake_builddir "${LLVM_BINARY_DIR}/${LLVM_INSTALL_PACKAGE_DIR}")
- 
- # First for users who use an installed LLVM, create the LLVMExports.cmake file.
-@@ -107,13 +107,13 @@ foreach(p ${_count})
-   set(LLVM_CONFIG_CODE "${LLVM_CONFIG_CODE}
- get_filename_component(LLVM_INSTALL_PREFIX \"\${LLVM_INSTALL_PREFIX}\" PATH)")
- endforeach(p)
--set(LLVM_CONFIG_INCLUDE_DIRS "\${LLVM_INSTALL_PREFIX}/include")
-+set(LLVM_CONFIG_INCLUDE_DIRS "\${LLVM_INSTALL_PREFIX}/${CMAKE_INSTALL_INCLUDEDIR}")
- set(LLVM_CONFIG_INCLUDE_DIR "${LLVM_CONFIG_INCLUDE_DIRS}")
- set(LLVM_CONFIG_MAIN_INCLUDE_DIR "${LLVM_CONFIG_INCLUDE_DIRS}")
--set(LLVM_CONFIG_LIBRARY_DIRS "\${LLVM_INSTALL_PREFIX}/lib\${LLVM_LIBDIR_SUFFIX}")
-+set(LLVM_CONFIG_LIBRARY_DIRS "\${LLVM_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}\${LLVM_LIBDIR_SUFFIX}")
- set(LLVM_CONFIG_CMAKE_DIR "\${LLVM_INSTALL_PREFIX}/${LLVM_INSTALL_PACKAGE_DIR}")
- set(LLVM_CONFIG_BINARY_DIR "\${LLVM_INSTALL_PREFIX}")
--set(LLVM_CONFIG_TOOLS_BINARY_DIR "\${LLVM_INSTALL_PREFIX}/bin")
-+set(LLVM_CONFIG_TOOLS_BINARY_DIR "\${LLVM_INSTALL_PREFIX}/${CMAKE_INSTALL_BINDIR}")
- 
- # Generate a default location for lit
- if (LLVM_INSTALL_UTILS AND LLVM_BUILD_UTILS)
-diff --git a/cmake/modules/LLVMInstallSymlink.cmake b/cmake/modules/LLVMInstallSymlink.cmake
-index 09fed8085c23..aa79f192abf0 100644
---- a/cmake/modules/LLVMInstallSymlink.cmake
-+++ b/cmake/modules/LLVMInstallSymlink.cmake
-@@ -10,7 +10,7 @@ function(install_symlink name target outdir)
-     set(LINK_OR_COPY copy)
-   endif()
- 
--  set(bindir "${DESTDIR}${CMAKE_INSTALL_PREFIX}/${outdir}/")
-+  set(bindir "${DESTDIR}${outdir}/")
- 
-   message(STATUS "Creating ${name}")
- 
-diff --git a/docs/CMake.rst b/docs/CMake.rst
-index bb821b417ad9..6a528f7c2ad3 100644
---- a/docs/CMake.rst
-+++ b/docs/CMake.rst
-@@ -196,7 +196,7 @@ CMake manual, or execute ``cmake --help-variable VARIABLE_NAME``.
- **LLVM_LIBDIR_SUFFIX**:STRING
-   Extra suffix to append to the directory where libraries are to be
-   installed. On a 64-bit architecture, one could use ``-DLLVM_LIBDIR_SUFFIX=64``
--  to install libraries to ``/usr/lib64``.
-+  to install libraries to ``/usr/lib64``. See also ``CMAKE_INSTALL_LIBDIR``.
- 
- **CMAKE_C_FLAGS**:STRING
-   Extra flags to use when compiling C source files.
-@@ -550,8 +550,8 @@ LLVM-specific variables
- 
- **LLVM_INSTALL_DOXYGEN_HTML_DIR**:STRING
-   The path to install Doxygen-generated HTML documentation to. This path can
--  either be absolute or relative to the CMAKE_INSTALL_PREFIX. Defaults to
--  `share/doc/llvm/doxygen-html`.
-+  either be absolute or relative to the ``CMAKE_INSTALL_PREFIX``. Defaults to
-+  `${CMAKE_INSTALL_DOCDIR}/${project}/doxygen-html`.
- 
- **LLVM_ENABLE_SPHINX**:BOOL
-   If specified, CMake will search for the ``sphinx-build`` executable and will make
-@@ -582,13 +582,33 @@ LLVM-specific variables
- 
- **LLVM_INSTALL_SPHINX_HTML_DIR**:STRING
-   The path to install Sphinx-generated HTML documentation to. This path can
--  either be absolute or relative to the CMAKE_INSTALL_PREFIX. Defaults to
--  `share/doc/llvm/html`.
-+  either be absolute or relative to the ``CMAKE_INSTALL_PREFIX``. Defaults to
-+  `${CMAKE_INSTALL_DOCDIR}/${project}/html`.
- 
- **LLVM_INSTALL_OCAMLDOC_HTML_DIR**:STRING
-   The path to install OCamldoc-generated HTML documentation to. This path can
--  either be absolute or relative to the CMAKE_INSTALL_PREFIX. Defaults to
--  `share/doc/llvm/ocaml-html`.
-+  either be absolute or relative to the ``CMAKE_INSTALL_PREFIX``. Defaults to
-+  `${CMAKE_INSTALL_DOCDIR}/${project}/ocaml-html`.
-+
-+**CMAKE_INSTALL_BINDIR**:STRING
-+  The path to install binary tools, relative to the ``CMAKE_INSTALL_PREFIX``.
-+  Defaults to `bin`.
-+
-+**CMAKE_INSTALL_LIBDIR**:STRING
-+  The path to install libraries, relative to the ``CMAKE_INSTALL_PREFIX``.
-+  Defaults to `lib`.
-+
-+**CMAKE_INSTALL_INCLUDEDIR**:STRING
-+  The path to install header files, relative to the ``CMAKE_INSTALL_PREFIX``.
-+  Defaults to `include`.
-+
-+**CMAKE_INSTALL_DOCDIR**:STRING
-+  The path to install documentation, relative to the ``CMAKE_INSTALL_PREFIX``.
-+  Defaults to `share/doc`.
-+
-+**CMAKE_INSTALL_MANDIR**:STRING
-+  The path to install manpage files, relative to the ``CMAKE_INSTALL_PREFIX``.
-+  Defaults to `share/man`.
- 
- **LLVM_CREATE_XCODE_TOOLCHAIN**:BOOL
-   macOS Only: If enabled CMake will generate a target named
-@@ -786,9 +806,11 @@ the ``cmake`` command or by setting it directly in ``ccmake`` or ``cmake-gui``).
- 
- This file is available in two different locations.
- 
--* ``<INSTALL_PREFIX>/lib/cmake/llvm/LLVMConfig.cmake`` where
--  ``<INSTALL_PREFIX>`` is the install prefix of an installed version of LLVM.
--  On Linux typically this is ``/usr/lib/cmake/llvm/LLVMConfig.cmake``.
-+* ``<LLVM_INSTALL_PACKAGE_DIR>LLVMConfig.cmake`` where
-+  ``<LLVM_INSTALL_PACKAGE_DIR>`` is the location where LLVM CMake modules are
-+  installed as part of an installed version of LLVM. This is typically
-+  ``cmake/llvm/`` within the lib directory. On Linux, this is typically
-+  ``/usr/lib/cmake/llvm/LLVMConfig.cmake``.
- 
- * ``<LLVM_BUILD_ROOT>/lib/cmake/llvm/LLVMConfig.cmake`` where
-   ``<LLVM_BUILD_ROOT>`` is the root of the LLVM build tree. **Note: this is only
-diff --git a/examples/Bye/CMakeLists.txt b/examples/Bye/CMakeLists.txt
-index bb96edb4b4bf..678c22fb43c8 100644
---- a/examples/Bye/CMakeLists.txt
-+++ b/examples/Bye/CMakeLists.txt
-@@ -14,6 +14,6 @@ if (NOT WIN32)
-     BUILDTREE_ONLY
-    )
- 
--  install(TARGETS ${name} RUNTIME DESTINATION examples)
-+  install(TARGETS ${name} RUNTIME DESTINATION ${CMAKE_INSTALL_DOCDIR}/examples)
-   set_target_properties(${name} PROPERTIES FOLDER "Examples")
- endif()
-diff --git a/include/llvm/CMakeLists.txt b/include/llvm/CMakeLists.txt
-index b46319f24fc8..2feabd1954e4 100644
---- a/include/llvm/CMakeLists.txt
-+++ b/include/llvm/CMakeLists.txt
-@@ -5,5 +5,5 @@ add_subdirectory(Frontend)
- # If we're doing an out-of-tree build, copy a module map for generated
- # header files into the build area.
- if (NOT "${CMAKE_SOURCE_DIR}" STREQUAL "${CMAKE_BINARY_DIR}")
--  configure_file(module.modulemap.build module.modulemap COPYONLY)
-+  configure_file(module.modulemap.build ${LLVM_INCLUDE_DIR}/module.modulemap COPYONLY)
- endif (NOT "${CMAKE_SOURCE_DIR}" STREQUAL "${CMAKE_BINARY_DIR}")
-diff --git a/tools/llvm-config/BuildVariables.inc.in b/tools/llvm-config/BuildVariables.inc.in
-index ebe5b73a5c65..70c497be12f5 100644
---- a/tools/llvm-config/BuildVariables.inc.in
-+++ b/tools/llvm-config/BuildVariables.inc.in
-@@ -23,6 +23,10 @@
- #define LLVM_CXXFLAGS "@LLVM_CXXFLAGS@"
- #define LLVM_BUILDMODE "@LLVM_BUILDMODE@"
- #define LLVM_LIBDIR_SUFFIX "@LLVM_LIBDIR_SUFFIX@"
-+#define LLVM_INSTALL_BINDIR "@CMAKE_INSTALL_BINDIR@"
-+#define LLVM_INSTALL_LIBDIR "@CMAKE_INSTALL_LIBDIR@"
-+#define LLVM_INSTALL_INCLUDEDIR "@CMAKE_INSTALL_INCLUDEDIR@"
-+#define LLVM_INSTALL_CMAKEDIR "@LLVM_INSTALL_CMAKE_DIR@"
- #define LLVM_TARGETS_BUILT "@LLVM_TARGETS_BUILT@"
- #define LLVM_SYSTEM_LIBS "@LLVM_SYSTEM_LIBS@"
- #define LLVM_BUILD_SYSTEM "@LLVM_BUILD_SYSTEM@"
-diff --git a/tools/llvm-config/llvm-config.cpp b/tools/llvm-config/llvm-config.cpp
-index 1a2f04552d13..44fa7d3eec6b 100644
---- a/tools/llvm-config/llvm-config.cpp
-+++ b/tools/llvm-config/llvm-config.cpp
-@@ -357,12 +357,26 @@ int main(int argc, char **argv) {
-         ("-I" + ActiveIncludeDir + " " + "-I" + ActiveObjRoot + "/include");
-   } else {
-     ActivePrefix = CurrentExecPrefix;
--    ActiveIncludeDir = ActivePrefix + "/include";
--    SmallString<256> path(StringRef(LLVM_TOOLS_INSTALL_DIR));
--    sys::fs::make_absolute(ActivePrefix, path);
--    ActiveBinDir = std::string(path.str());
--    ActiveLibDir = ActivePrefix + "/lib" + LLVM_LIBDIR_SUFFIX;
--    ActiveCMakeDir = ActiveLibDir + "/cmake/llvm";
-+    {
-+      SmallString<256> path(StringRef(LLVM_INSTALL_INCLUDEDIR));
-+      sys::fs::make_absolute(ActivePrefix, path);
-+      ActiveIncludeDir = std::string(path.str());
-+    }
-+    {
-+      SmallString<256> path(StringRef(LLVM_INSTALL_BINDIR));
-+      sys::fs::make_absolute(ActivePrefix, path);
-+      ActiveBinDir = std::string(path.str());
-+    }
-+    {
-+      SmallString<256> path(StringRef(LLVM_INSTALL_LIBDIR LLVM_LIBDIR_SUFFIX));
-+      sys::fs::make_absolute(ActivePrefix, path);
-+      ActiveLibDir = std::string(path.str());
-+    }
-+    {
-+      SmallString<256> path(StringRef(LLVM_INSTALL_CMAKEDIR));
-+      sys::fs::make_absolute(ActivePrefix, path);
-+      ActiveCMakeDir = std::string(path.str());
-+    }
-     ActiveIncludeOption = "-I" + ActiveIncludeDir;
-   }
- 
-diff --git a/tools/lto/CMakeLists.txt b/tools/lto/CMakeLists.txt
-index 2963f97cad88..69d66c9c9ca1 100644
---- a/tools/lto/CMakeLists.txt
-+++ b/tools/lto/CMakeLists.txt
-@@ -25,7 +25,7 @@ add_llvm_library(LTO SHARED INSTALL_WITH_TOOLCHAIN ${SOURCES} DEPENDS
-     intrinsics_gen)
- 
- install(FILES ${LLVM_MAIN_INCLUDE_DIR}/llvm-c/lto.h
--  DESTINATION include/llvm-c
-+  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/llvm-c
-   COMPONENT LTO)
- 
- if (APPLE)
-diff --git a/tools/opt-viewer/CMakeLists.txt b/tools/opt-viewer/CMakeLists.txt
-index ead73ec13a8f..250362021f17 100644
---- a/tools/opt-viewer/CMakeLists.txt
-+++ b/tools/opt-viewer/CMakeLists.txt
-@@ -8,7 +8,7 @@ set (files
- 
- foreach (file ${files})
-   install(PROGRAMS ${file}
--    DESTINATION share/opt-viewer
-+    DESTINATION ${CMAKE_INSTALL_DATADIR}/opt-viewer
-     COMPONENT opt-viewer)
- endforeach (file)
- 
-diff --git a/tools/remarks-shlib/CMakeLists.txt b/tools/remarks-shlib/CMakeLists.txt
-index 865436247270..ce1daa62f6ab 100644
---- a/tools/remarks-shlib/CMakeLists.txt
-+++ b/tools/remarks-shlib/CMakeLists.txt
-@@ -19,7 +19,7 @@ if(LLVM_ENABLE_PIC)
-   endif()
-   
-   install(FILES ${LLVM_MAIN_INCLUDE_DIR}/llvm-c/Remarks.h
--    DESTINATION include/llvm-c
-+    DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/llvm-c
-     COMPONENT Remarks)
- 
-   if (APPLE)
diff --git a/pkgs/development/compilers/llvm/12/clang/gnu-install-dirs.patch b/pkgs/development/compilers/llvm/13/clang/gnu-install-dirs.patch
similarity index 100%
rename from pkgs/development/compilers/llvm/12/clang/gnu-install-dirs.patch
rename to pkgs/development/compilers/llvm/13/clang/gnu-install-dirs.patch
diff --git a/pkgs/development/compilers/llvm/12/clang/purity.patch b/pkgs/development/compilers/llvm/13/clang/purity.patch
similarity index 100%
rename from pkgs/development/compilers/llvm/12/clang/purity.patch
rename to pkgs/development/compilers/llvm/13/clang/purity.patch
diff --git a/pkgs/development/compilers/llvm/12/compiler-rt/X86-support-extension.patch b/pkgs/development/compilers/llvm/13/compiler-rt/X86-support-extension.patch
similarity index 100%
rename from pkgs/development/compilers/llvm/12/compiler-rt/X86-support-extension.patch
rename to pkgs/development/compilers/llvm/13/compiler-rt/X86-support-extension.patch
diff --git a/pkgs/development/compilers/llvm/12/compiler-rt/gnu-install-dirs.patch b/pkgs/development/compilers/llvm/13/compiler-rt/gnu-install-dirs.patch
similarity index 100%
rename from pkgs/development/compilers/llvm/12/compiler-rt/gnu-install-dirs.patch
rename to pkgs/development/compilers/llvm/13/compiler-rt/gnu-install-dirs.patch
diff --git a/pkgs/development/compilers/llvm/12/compiler-rt/normalize-var.patch b/pkgs/development/compilers/llvm/13/compiler-rt/normalize-var.patch
similarity index 100%
rename from pkgs/development/compilers/llvm/12/compiler-rt/normalize-var.patch
rename to pkgs/development/compilers/llvm/13/compiler-rt/normalize-var.patch
diff --git a/pkgs/development/compilers/llvm/12/lld/gnu-install-dirs.patch b/pkgs/development/compilers/llvm/13/lld/gnu-install-dirs.patch
similarity index 100%
rename from pkgs/development/compilers/llvm/12/lld/gnu-install-dirs.patch
rename to pkgs/development/compilers/llvm/13/lld/gnu-install-dirs.patch
diff --git a/pkgs/development/compilers/llvm/12/lldb/procfs.patch b/pkgs/development/compilers/llvm/13/lldb/procfs.patch
similarity index 100%
rename from pkgs/development/compilers/llvm/12/lldb/procfs.patch
rename to pkgs/development/compilers/llvm/13/lldb/procfs.patch
diff --git a/pkgs/development/compilers/llvm/12/lldb/resource-dir.patch b/pkgs/development/compilers/llvm/13/lldb/resource-dir.patch
similarity index 100%
rename from pkgs/development/compilers/llvm/12/lldb/resource-dir.patch
rename to pkgs/development/compilers/llvm/13/lldb/resource-dir.patch
diff --git a/pkgs/development/compilers/llvm/12/llvm/no-pipes.patch b/pkgs/development/compilers/llvm/13/llvm/no-pipes.patch
similarity index 100%
rename from pkgs/development/compilers/llvm/12/llvm/no-pipes.patch
rename to pkgs/development/compilers/llvm/13/llvm/no-pipes.patch
diff --git a/pkgs/development/compilers/llvm/common/bintools.nix b/pkgs/development/compilers/llvm/common/bintools.nix
index 24af8c618e91..fa3228ecff28 100644
--- a/pkgs/development/compilers/llvm/common/bintools.nix
+++ b/pkgs/development/compilers/llvm/common/bintools.nix
@@ -22,42 +22,38 @@ runCommand "llvm-binutils-${version}"
       inherit llvm lld;
     };
   }
-  (
-    ''
-      mkdir -p $out/bin
-      for prog in ${lld}/bin/*; do
-        ln -s $prog $out/bin/${targetPrefix}$(basename $prog)
-      done
-      for prog in ${llvm}/bin/*; do
-        ln -sf $prog $out/bin/${targetPrefix}$(basename $prog)
-      done
+  ''
+    mkdir -p $out/bin
+    for prog in ${lld}/bin/*; do
+      ln -s $prog $out/bin/${targetPrefix}$(basename $prog)
+    done
+    for prog in ${llvm}/bin/*; do
+      ln -sf $prog $out/bin/${targetPrefix}$(basename $prog)
+    done
 
-      llvmBin="${llvm}/bin"
+    llvmBin="${llvm}/bin"
 
-      ln -s $llvmBin/llvm-ar $out/bin/${targetPrefix}ar
-      ln -s $llvmBin/llvm-ar $out/bin/${targetPrefix}dlltool
-      ln -s $llvmBin/llvm-ar $out/bin/${targetPrefix}ranlib
-      ln -s $llvmBin/llvm-cxxfilt $out/bin/${targetPrefix}c++filt
-      ln -s $llvmBin/llvm-dwp $out/bin/${targetPrefix}dwp
-      ln -s $llvmBin/llvm-nm $out/bin/${targetPrefix}nm
-      ln -s $llvmBin/llvm-objcopy $out/bin/${targetPrefix}objcopy
-      ln -s $llvmBin/llvm-objcopy $out/bin/${targetPrefix}strip
-      ln -s $llvmBin/llvm-objdump $out/bin/${targetPrefix}objdump
-      ln -s $llvmBin/llvm-readobj $out/bin/${targetPrefix}readelf
-      ln -s $llvmBin/llvm-size $out/bin/${targetPrefix}size
-      ln -s $llvmBin/llvm-strings $out/bin/${targetPrefix}strings
-      ln -s $llvmBin/llvm-symbolizer $out/bin/${targetPrefix}addr2line
+    ln -s $llvmBin/llvm-ar $out/bin/${targetPrefix}ar
+    ln -s $llvmBin/llvm-ar $out/bin/${targetPrefix}dlltool
+    ln -s $llvmBin/llvm-ar $out/bin/${targetPrefix}ranlib
+    ln -s $llvmBin/llvm-cxxfilt $out/bin/${targetPrefix}c++filt
+    ln -s $llvmBin/llvm-dwp $out/bin/${targetPrefix}dwp
+    ln -s $llvmBin/llvm-nm $out/bin/${targetPrefix}nm
+    ln -s $llvmBin/llvm-objcopy $out/bin/${targetPrefix}objcopy
+    ln -s $llvmBin/llvm-objcopy $out/bin/${targetPrefix}strip
+    ln -s $llvmBin/llvm-objdump $out/bin/${targetPrefix}objdump
+    ln -s $llvmBin/llvm-readobj $out/bin/${targetPrefix}readelf
+    ln -s $llvmBin/llvm-size $out/bin/${targetPrefix}size
+    ln -s $llvmBin/llvm-strings $out/bin/${targetPrefix}strings
+    ln -s $llvmBin/llvm-symbolizer $out/bin/${targetPrefix}addr2line
 
-      if [ -e "$llvmBin/llvm-debuginfod" ]; then
-        ln -s $llvmBin/llvm-debuginfod $out/bin/${targetPrefix}debuginfod
-        ln -s $llvmBin/llvm-debuginfod-find $out/bin/${targetPrefix}debuginfod-find
-      fi
+    if [ -e "$llvmBin/llvm-debuginfod" ]; then
+      ln -s $llvmBin/llvm-debuginfod $out/bin/${targetPrefix}debuginfod
+      ln -s $llvmBin/llvm-debuginfod-find $out/bin/${targetPrefix}debuginfod-find
+    fi
 
-      ln -s ${lld}/bin/lld $out/bin/${targetPrefix}ld
+    ln -s ${lld}/bin/lld $out/bin/${targetPrefix}ld
 
-      # Only >=13 show GNU windres compatible in help
-    ''
-    + lib.optionalString (lib.versionAtLeast release_version "13") ''
-      ln -s $llvmBin/llvm-rc $out/bin/${targetPrefix}windres
-    ''
-  )
+    # Only >=13 show GNU windres compatible in help
+    ln -s $llvmBin/llvm-rc $out/bin/${targetPrefix}windres
+  ''
diff --git a/pkgs/development/compilers/llvm/common/compiler-rt/default.nix b/pkgs/development/compilers/llvm/common/compiler-rt/default.nix
index 40ff633527ae..66878a5c2776 100644
--- a/pkgs/development/compilers/llvm/common/compiler-rt/default.nix
+++ b/pkgs/development/compilers/llvm/common/compiler-rt/default.nix
@@ -84,27 +84,17 @@ stdenv.mkDerivation (finalAttrs: {
       # Fix build on armv6l
       ./armv6-no-ldrexd-strexd.patch
     ]
-    ++ lib.optional (lib.versions.major release_version == "12") (fetchpatch {
-      # fixes the parallel build on aarch64 darwin
-      name = "fix-symlink-race-aarch64-darwin.patch";
-      url = "https://github.com/llvm/llvm-project/commit/b31080c596246bc26d2493cfd5e07f053cf9541c.patch";
-      relative = "compiler-rt";
-      hash = "sha256-Cv2NC8402yU7QaTR6TzdH+qyWRy+tTote7KKWtKRWFQ=";
+    ++ lib.optional (lib.versionAtLeast release_version "14" && lib.versionOlder release_version "18") (
+      getVersionFile "compiler-rt/gnu-install-dirs.patch"
+    )
+    ++ lib.optional (lib.versionOlder release_version "18") (fetchpatch {
+      name = "cfi_startproc-after-label.patch";
+      url = "https://github.com/llvm/llvm-project/commit/7939ce39dac0078fef7183d6198598b99c652c88.patch";
+      stripLen = 1;
+      hash = "sha256-tGqXsYvUllFrPa/r/dsKVlwx5IrcJGccuR1WAtUg7/o=";
     })
-    ++ lib.optional (
-      lib.versions.major release_version == "12"
-      || (lib.versionAtLeast release_version "14" && lib.versionOlder release_version "18")
-    ) (getVersionFile "compiler-rt/gnu-install-dirs.patch")
     ++
-      lib.optional (lib.versionAtLeast release_version "13" && lib.versionOlder release_version "18")
-        (fetchpatch {
-          name = "cfi_startproc-after-label.patch";
-          url = "https://github.com/llvm/llvm-project/commit/7939ce39dac0078fef7183d6198598b99c652c88.patch";
-          stripLen = 1;
-          hash = "sha256-tGqXsYvUllFrPa/r/dsKVlwx5IrcJGccuR1WAtUg7/o=";
-        })
-    ++
-      lib.optional (lib.versionAtLeast release_version "13" && lib.versionOlder release_version "18")
+      lib.optional (lib.versionOlder release_version "18")
         # Prevent a compilation error on darwin
         (getVersionFile "compiler-rt/darwin-targetconditionals.patch")
     # TODO: make unconditional and remove in <15 section below. Causes rebuilds.
@@ -123,13 +113,11 @@ stdenv.mkDerivation (finalAttrs: {
       ./armv6-mcr-dmb.patch
       ./armv6-sync-ops-no-thumb.patch
     ]
-    ++
-      lib.optionals (lib.versionAtLeast release_version "13" && lib.versionOlder release_version "18")
-        [
-          # Fix build on armv6l
-          ./armv6-scudo-no-yield.patch
-        ]
-    ++ lib.optionals (lib.versionAtLeast release_version "13") [
+    ++ lib.optionals (lib.versionOlder release_version "18") [
+      # Fix build on armv6l
+      ./armv6-scudo-no-yield.patch
+    ]
+    ++ [
       (getVersionFile "compiler-rt/armv6-scudo-libatomic.patch")
     ]
     ++ lib.optional (lib.versions.major release_version == "19") (fetchpatch {
@@ -277,16 +265,13 @@ stdenv.mkDerivation (finalAttrs: {
         ''
       )
     )
-    +
-      lib.optionalString
-        (lib.versionAtLeast release_version "13" && lib.versionOlder release_version "14")
-        ''
-          # https://github.com/llvm/llvm-project/blob/llvmorg-14.0.6/libcxx/utils/merge_archives.py
-          # Seems to only be used in v13 though it's present in v12 and v14, and dropped in v15.
-          substituteInPlace ../libcxx/utils/merge_archives.py \
-            --replace-fail "import distutils.spawn" "from shutil import which as find_executable" \
-            --replace-fail "distutils.spawn." ""
-        ''
+    + lib.optionalString (lib.versionOlder release_version "14") ''
+      # https://github.com/llvm/llvm-project/blob/llvmorg-14.0.6/libcxx/utils/merge_archives.py
+      # Seems to only be used in v13 though it's present in v12 and v14, and dropped in v15.
+      substituteInPlace ../libcxx/utils/merge_archives.py \
+        --replace-fail "import distutils.spawn" "from shutil import which as find_executable" \
+        --replace-fail "distutils.spawn." ""
+    ''
     +
       lib.optionalString (lib.versionAtLeast release_version "19")
         # codesign in sigtool doesn't support the various options used by the build
diff --git a/pkgs/development/compilers/llvm/common/libcxx/default.nix b/pkgs/development/compilers/llvm/common/libcxx/default.nix
index 520692c30d6e..dad04c475207 100644
--- a/pkgs/development/compilers/llvm/common/libcxx/default.nix
+++ b/pkgs/development/compilers/llvm/common/libcxx/default.nix
@@ -113,16 +113,8 @@ let
   cmakeFlags = [
     (lib.cmakeFeature "LLVM_ENABLE_RUNTIMES" (lib.concatStringsSep ";" runtimes))
   ]
-  ++
-    lib.optionals
-      (
-        stdenv.hostPlatform.isWasm
-        || (lib.versions.major release_version == "12" && stdenv.hostPlatform.isDarwin)
-      )
-      [
-        (lib.cmakeBool "CMAKE_CXX_COMPILER_WORKS" true)
-      ]
   ++ lib.optionals stdenv.hostPlatform.isWasm [
+    (lib.cmakeBool "CMAKE_CXX_COMPILER_WORKS" true)
     (lib.cmakeBool "CMAKE_C_COMPILER_WORKS" true)
     (lib.cmakeBool "UNIX" true) # Required otherwise libc++ fails to detect the correct linker
   ]
diff --git a/pkgs/development/compilers/llvm/common/libunwind/default.nix b/pkgs/development/compilers/llvm/common/libunwind/default.nix
index 188ba578c994..27dc4e6614f2 100644
--- a/pkgs/development/compilers/llvm/common/libunwind/default.nix
+++ b/pkgs/development/compilers/llvm/common/libunwind/default.nix
@@ -80,9 +80,6 @@ stdenv.mkDerivation (
     ++ lib.optional (lib.versionAtLeast release_version "15") (
       lib.cmakeFeature "LLVM_ENABLE_RUNTIMES" "libunwind"
     )
-    ++ lib.optionals (lib.versions.major release_version == "12" && stdenv.hostPlatform.isDarwin) [
-      (lib.cmakeBool "CMAKE_CXX_COMPILER_WORKS" true)
-    ]
     ++ devExtraCmakeFlags;
 
     prePatch =
diff --git a/pkgs/development/compilers/llvm/common/lldb/default.nix b/pkgs/development/compilers/llvm/common/lldb/default.nix
index 5de0fec60877..648d44ca894f 100644
--- a/pkgs/development/compilers/llvm/common/lldb/default.nix
+++ b/pkgs/development/compilers/llvm/common/lldb/default.nix
@@ -72,7 +72,7 @@ stdenv.mkDerivation (
       "dev"
     ];
 
-    sourceRoot = lib.optional (lib.versionAtLeast release_version "13") "${finalAttrs.src.name}/lldb";
+    sourceRoot = "${finalAttrs.src.name}/lldb";
 
     patches =
       let
diff --git a/pkgs/development/compilers/llvm/common/llvm/default.nix b/pkgs/development/compilers/llvm/common/llvm/default.nix
index daf88e25b34e..ee39561a8a62 100644
--- a/pkgs/development/compilers/llvm/common/llvm/default.nix
+++ b/pkgs/development/compilers/llvm/common/llvm/default.nix
@@ -129,18 +129,6 @@ stdenv.mkDerivation (
         # a native libLLVM.so (which would fail) we force llvm-config to be linked
         # statically against the necessary LLVM components always.
         ./llvm-config-link-static.patch
-      ++ lib.optionals (lib.versions.major release_version == "12") [
-        # Fix llvm being miscompiled by some gccs. See https://github.com/llvm/llvm-project/issues/49955
-        (getVersionFile "llvm/fix-llvm-issue-49955.patch")
-
-        # On older CPUs (e.g. Hydra/wendy) we'd be getting an error in this test.
-        (fetchpatch {
-          name = "uops-CMOV16rm-noreg.diff";
-          url = "https://github.com/llvm/llvm-project/commit/9e9f991ac033.diff";
-          sha256 = "sha256:12s8vr6ibri8b48h2z38f3afhwam10arfiqfy4yg37bmc054p5hi";
-          stripLen = 1;
-        })
-      ]
       # Support custom installation dirs
       # Originally based off https://reviews.llvm.org/D99484
       # Latest state: https://github.com/llvm/llvm-project/pull/125376
@@ -339,6 +327,11 @@ stdenv.mkDerivation (
       ) ncurses)
       ++ [ zlib ];
 
+    nativeCheckInputs = [
+      which
+    ]
+    ++ lib.optional (stdenv.hostPlatform.isDarwin && lib.versionAtLeast release_version "15") sysctl;
+
     postPatch =
       optionalString stdenv.hostPlatform.isDarwin (
         ''
@@ -470,14 +463,8 @@ stdenv.mkDerivation (
           substituteInPlace unittests/IR/CMakeLists.txt \
             --replace-fail "PassBuilderCallbacksTest.cpp" ""
           rm unittests/IR/PassBuilderCallbacksTest.cpp
+          rm test/tools/llvm-objcopy/ELF/mirror-permissions-unix.test
         ''
-      + lib.optionalString (lib.versionAtLeast release_version "13") ''
-        rm test/tools/llvm-objcopy/ELF/mirror-permissions-unix.test
-      ''
-      + lib.optionalString (lib.versionOlder release_version "13") ''
-        # TODO: Fix failing tests:
-        rm test/DebugInfo/X86/vla-multi.ll
-      ''
       +
         # Fails in the presence of anti-virus software or other intrusion-detection software that
         # modifies the atime when run. See #284056.
@@ -540,44 +527,7 @@ stdenv.mkDerivation (
         ''
       + ''
         patchShebangs test/BugPoint/compile-custom.ll.py
-      ''
-      +
-        # Tweak tests to ignore namespace part of type to support
-        # gcc-12: https://gcc.gnu.org/PR103598.
-        # The change below mangles strings like:
-        #    CHECK-NEXT: Starting llvm::Function pass manager run.
-        # to:
-        #    CHECK-NEXT: Starting {{.*}}Function pass manager run.
-        (lib.optionalString (lib.versionOlder release_version "13") (
-          ''
-            for f in \
-              test/Other/new-pass-manager.ll \
-              test/Other/new-pm-O0-defaults.ll \
-              test/Other/new-pm-defaults.ll \
-              test/Other/new-pm-lto-defaults.ll \
-              test/Other/new-pm-thinlto-defaults.ll \
-              test/Other/pass-pipeline-parsing.ll \
-              test/Transforms/Inline/cgscc-incremental-invalidate.ll \
-              test/Transforms/Inline/clear-analyses.ll \
-              test/Transforms/LoopUnroll/unroll-loop-invalidation.ll \
-              test/Transforms/SCCP/ipsccp-preserve-analysis.ll \
-              test/Transforms/SCCP/preserve-analysis.ll \
-              test/Transforms/SROA/dead-inst.ll \
-              test/tools/gold/X86/new-pm.ll \
-              ; do
-              echo "PATCH: $f"
-              substituteInPlace $f \
-                --replace-quiet 'Starting llvm::' 'Starting {{.*}}' \
-                --replace-quiet 'Finished llvm::' 'Finished {{.*}}'
-            done
-          ''
-          +
-            # gcc-13 fix
-            ''
-              sed -i '/#include <string>/i#include <cstdint>' \
-                include/llvm/DebugInfo/Symbolize/DIPrinter.h
-            ''
-        ));
+      '';
 
     # Workaround for configure flags that need to have spaces
     preConfigure = ''
@@ -810,12 +760,6 @@ stdenv.mkDerivation (
         }
     )
   )
-  // lib.optionalAttrs (lib.versionAtLeast release_version "13") {
-    nativeCheckInputs = [
-      which
-    ]
-    ++ lib.optional (stdenv.hostPlatform.isDarwin && lib.versionAtLeast release_version "15") sysctl;
-  }
   // lib.optionalAttrs (lib.versionOlder release_version "15") {
     # hacky fix: created binaries need to be run before installation
     preBuild = ''
diff --git a/pkgs/development/compilers/llvm/common/patches.nix b/pkgs/development/compilers/llvm/common/patches.nix
index 21eb8c4471c3..811195695cc4 100644
--- a/pkgs/development/compilers/llvm/common/patches.nix
+++ b/pkgs/development/compilers/llvm/common/patches.nix
@@ -2,7 +2,7 @@
   "clang/gnu-install-dirs.patch" = [
     {
       before = "14";
-      path = ../12;
+      path = ../13;
     }
     {
       after = "19";
@@ -21,7 +21,7 @@
     }
     {
       before = "16";
-      path = ../12;
+      path = ../13;
     }
   ];
   "clang/aarch64-tblgen.patch" = [
@@ -44,7 +44,7 @@
     }
     {
       before = "14";
-      path = ../12;
+      path = ../13;
     }
   ];
   "llvm/gnu-install-dirs.patch" = [
@@ -126,7 +126,7 @@
     }
     {
       before = "15";
-      path = ../12;
+      path = ../13;
     }
   ];
   "compiler-rt/armv6-scudo-libatomic.patch" = [
@@ -147,17 +147,15 @@
   "compiler-rt/armv7l.patch" = [
     {
       before = "15";
-      after = "13";
       path = ../13;
     }
   ];
   "compiler-rt/gnu-install-dirs.patch" = [
     {
       before = "14";
-      path = ../12;
+      path = ../13;
     }
     {
-      after = "13";
       before = "15";
       path = ../14;
     }
@@ -173,13 +171,11 @@
   ];
   "compiler-rt/darwin-targetconditionals.patch" = [
     {
-      after = "13";
       path = ../13;
     }
   ];
   "compiler-rt/codesign.patch" = [
     {
-      after = "13";
       path = ../13;
     }
   ];
@@ -190,7 +186,7 @@
     }
     {
       before = "16";
-      path = ../12;
+      path = ../13;
     }
   ];
   "lldb/procfs.patch" = [
@@ -200,19 +196,19 @@
     }
     {
       before = "15";
-      path = ../12;
+      path = ../13;
     }
   ];
   "lldb/resource-dir.patch" = [
     {
       before = "16";
-      path = ../12;
+      path = ../13;
     }
   ];
   "llvm/no-pipes.patch" = [
     {
       before = "16";
-      path = ../12;
+      path = ../13;
     }
   ];
   "openmp/fix-find-tool.patch" = [
diff --git a/pkgs/development/compilers/llvm/default.nix b/pkgs/development/compilers/llvm/default.nix
index f5b86b1c3312..3f0738e4a54c 100644
--- a/pkgs/development/compilers/llvm/default.nix
+++ b/pkgs/development/compilers/llvm/default.nix
@@ -22,7 +22,6 @@
 }@packageSetArgs:
 let
   versions = {
-    "12.0.1".officialRelease.sha256 = "08s5w2db9imb2yaqsvxs6pg21csi1cf6wa35rf8x6q07mam7j8qv";
     "13.0.1".officialRelease.sha256 = "06dv6h5dmvzdxbif2s8njki6h32796v368dyb5945x8gjj72xh7k";
     "14.0.6".officialRelease.sha256 = "sha256-vffu4HilvYwtzwgq+NlS26m65DGbp6OSSne2aje1yJE=";
     "15.0.7".officialRelease.sha256 = "sha256-wjuZQyXQ/jsmvy6y1aksCcEDXGBjuhpgngF3XQJ/T4s=";
diff --git a/pkgs/development/compilers/llvm/update.sh b/pkgs/development/compilers/llvm/update.sh
index 95ad356dbd9a..ee742a206ef1 100755
--- a/pkgs/development/compilers/llvm/update.sh
+++ b/pkgs/development/compilers/llvm/update.sh
@@ -24,23 +24,9 @@ if [ "$VERSION_MAJOR" -ge "14" ]; then
   readonly SOURCES=(
     "llvm.monorepoSrc"
   )
-elif [ "$VERSION_MAJOR" -eq "13" ]; then
-  readonly SOURCES=(
-    "llvm.src"
-  )
 else
   readonly SOURCES=(
-    "clang-unwrapped.src"
-    "compiler-rt.src"
-    "clang-unwrapped.clang-tools-extra_src"
-    "libcxx.src"
-    "libcxxabi.src"
-    "libunwind.src"
-    "lld.src"
-    "lldb.src"
     "llvm.src"
-    "llvm.polly_src"
-    "openmp.src"
   )
 fi
 
diff --git a/pkgs/test/default.nix b/pkgs/test/default.nix
index 1335cb8b5e73..118c30b0f175 100644
--- a/pkgs/test/default.nix
+++ b/pkgs/test/default.nix
@@ -16,6 +16,7 @@ with pkgs;
             (filter (n: n != "llvmPackages_9"))
             (filter (n: n != "llvmPackages_10"))
             (filter (n: n != "llvmPackages_11"))
+            (filter (n: n != "llvmPackages_12"))
           ];
           tests = lib.genAttrs pkgSets (
             name:
diff --git a/pkgs/top-level/aliases.nix b/pkgs/top-level/aliases.nix
index 73a5d74cd570..0f5f40831637 100644
--- a/pkgs/top-level/aliases.nix
+++ b/pkgs/top-level/aliases.nix
@@ -698,8 +698,6 @@ mapAliases {
   cyber = throw "cyber has been removed, as it does not build with supported Zig versions"; # Added 2025-08-09
 
   # these are for convenience, not for backward compat., and shouldn't expire until the package is deprecated.
-  clang9Stdenv = throw "clang9Stdenv has been removed from nixpkgs"; # Added 2024-04-08
-  clang12Stdenv = lowPrio llvmPackages_12.stdenv; # preserve, reason: see above
   clang13Stdenv = lowPrio llvmPackages_13.stdenv; # preserve, reason: see above
   clang14Stdenv = lowPrio llvmPackages_14.stdenv; # preserve, reason: see above
   clang15Stdenv = lowPrio llvmPackages_15.stdenv; # preserve, reason: see above
@@ -708,10 +706,6 @@ mapAliases {
   clang18Stdenv = lowPrio llvmPackages_18.stdenv; # preserve, reason: see above
   clang19Stdenv = lowPrio llvmPackages_19.stdenv; # preserve, reason: see above
 
-  clang-tools_9 = throw "clang-tools_9 has been removed from nixpkgs"; # Added 2024-04-08
-  clang_9 = throw "clang_9 has been removed from nixpkgs"; # Added 2024-04-08
-
-  clang-tools_12 = llvmPackages_12.clang-tools; # Added 2024-04-22
   clang-tools_13 = llvmPackages_13.clang-tools; # Added 2024-04-22
   clang-tools_14 = llvmPackages_14.clang-tools; # Added 2024-04-22
   clang-tools_15 = llvmPackages_15.clang-tools; # Added 2024-04-22
@@ -1485,10 +1479,21 @@ mapAliases {
 
   llvmPackages_git = (callPackages ../development/compilers/llvm { }).git; # Added 2024-08-02
 
-  lld_9 = throw "lld_9 has been removed from nixpkgs"; # Added 2024-04-08
-  lldb_9 = throw "lldb_9 has been removed from nixpkgs"; # Added 2024-04-08
   llvmPackages_9 = throw "llvmPackages_9 has been removed from nixpkgs"; # Added 2024-04-08
   llvm_9 = throw "llvm_9 has been removed from nixpkgs"; # Added 2024-04-08
+  lld_9 = throw "lld_9 has been removed from nixpkgs"; # Added 2024-04-08
+  lldb_9 = throw "lldb_9 has been removed from nixpkgs"; # Added 2024-04-08
+  clang_9 = throw "clang_9 has been removed from nixpkgs"; # Added 2024-04-08
+  clang9Stdenv = throw "clang9Stdenv has been removed from nixpkgs"; # Added 2024-04-08
+  clang-tools_9 = throw "clang-tools_9 has been removed from nixpkgs"; # Added 2024-04-08
+
+  llvmPackages_12 = throw "llvmPackages_12 has been removed, as it is unmaintained and obsolete"; # Added 2025-08-10
+  llvm_12 = throw "llvm_12 has been removed, as it is unmaintained and obsolete"; # Added 2025-08-10
+  lld_12 = throw "lld_12 has been removed, as it is unmaintained and obsolete"; # Added 2025-08-10
+  lldb_12 = throw "lldb_12 has been removed, as it is unmaintained and obsolete"; # Added 2025-08-10
+  clang_12 = throw "clang_12 has been removed, as it is unmaintained and obsolete"; # Added 2025-08-10
+  clang12Stdenv = throw "clang12Stdenv has been removed, as it is unmaintained and obsolete"; # Added 2025-08-10
+  clang-tools_12 = throw "clang-tools_12 has been removed, as it is unmaintained and obsolete"; # Added 2025-08-10
 
   lobster-two = throw "'lobster-two' has been renamed to/replaced by 'google-fonts'"; # Converted to throw 2024-10-17
   loc = throw "'loc' has been removed due to lack of upstream maintenance. Consider 'tokei' as an alternative."; # Added 2025-01-25
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 2d8f2ea5d7dc..67e3b46486f4 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -4633,7 +4633,6 @@ with pkgs;
   clang-manpages = llvmPackages.clang-manpages;
 
   clang = llvmPackages.clang;
-  clang_12 = llvmPackages_12.clang;
   clang_13 = llvmPackages_13.clang;
   clang_14 = llvmPackages_14.clang;
   clang_15 = llvmPackages_15.clang;
@@ -5365,7 +5364,6 @@ with pkgs;
   };
 
   lld = llvmPackages.lld;
-  lld_12 = llvmPackages_12.lld;
   lld_13 = llvmPackages_13.lld;
   lld_14 = llvmPackages_14.lld;
   lld_15 = llvmPackages_15.lld;
@@ -5373,7 +5371,6 @@ with pkgs;
   lld_17 = llvmPackages_17.lld;
 
   lldb = llvmPackages.lldb;
-  lldb_12 = llvmPackages_12.lldb;
   lldb_13 = llvmPackages_13.lldb;
   lldb_14 = llvmPackages_14.lldb;
   lldb_15 = llvmPackages_15.lldb;
@@ -5381,7 +5378,6 @@ with pkgs;
   lldb_17 = llvmPackages_17.lldb;
 
   llvm = llvmPackages.llvm;
-  llvm_12 = llvmPackages_12.llvm;
   llvm_13 = llvmPackages_13.llvm;
   llvm_14 = llvmPackages_14.llvm;
   llvm_15 = llvmPackages_15.llvm;
@@ -5402,7 +5398,6 @@ with pkgs;
     (rec {
       llvmPackagesSet = recurseIntoAttrs (callPackages ../development/compilers/llvm { });
 
-      llvmPackages_12 = llvmPackagesSet."12";
       llvmPackages_13 = llvmPackagesSet."13";
       llvmPackages_14 = llvmPackagesSet."14";
       llvmPackages_15 = llvmPackagesSet."15";
@@ -5440,7 +5435,6 @@ with pkgs;
 
       mkLLVMPackages = llvmPackagesSet.mkPackage;
     })
-    llvmPackages_12
     llvmPackages_13
     llvmPackages_14
     llvmPackages_15