diff --git a/pkgs/development/compilers/llvm/common/bolt/default.nix b/pkgs/development/compilers/llvm/common/bolt/default.nix
index 9d6385ae74b3..d62841b48d0a 100644
--- a/pkgs/development/compilers/llvm/common/bolt/default.nix
+++ b/pkgs/development/compilers/llvm/common/bolt/default.nix
@@ -3,6 +3,7 @@
   stdenv,
   llvm_meta,
   monorepoSrc,
+  release_version,
   runCommand,
   cmake,
   libxml2,
@@ -20,16 +21,22 @@ stdenv.mkDerivation (finalAttrs: {
   inherit version patches;
 
   # Blank llvm dir just so relative path works
-  src = runCommand "bolt-src-${finalAttrs.version}" { } ''
-    mkdir $out
-    cp -r ${monorepoSrc}/cmake "$out"
-    cp -r ${monorepoSrc}/${finalAttrs.pname} "$out"
-    cp -r ${monorepoSrc}/third-party "$out"
+  src = runCommand "bolt-src-${finalAttrs.version}" { } (
+    ''
+      mkdir $out
+    ''
+    + lib.optionalString (lib.versionAtLeast release_version "14") ''
+      cp -r ${monorepoSrc}/cmake "$out"
+    ''
+    + ''
+      cp -r ${monorepoSrc}/${finalAttrs.pname} "$out"
+      cp -r ${monorepoSrc}/third-party "$out"
 
-    # tablegen stuff, probably not the best way but it works...
-    cp -r ${monorepoSrc}/llvm/ "$out"
-    chmod -R +w $out/llvm
-  '';
+      # tablegen stuff, probably not the best way but it works...
+      cp -r ${monorepoSrc}/llvm/ "$out"
+      chmod -R +w $out/llvm
+    ''
+  );
 
   sourceRoot = "${finalAttrs.src.name}/bolt";
 
diff --git a/pkgs/development/compilers/llvm/common/clang/default.nix b/pkgs/development/compilers/llvm/common/clang/default.nix
index 2b5aca109348..5c9662c24d58 100644
--- a/pkgs/development/compilers/llvm/common/clang/default.nix
+++ b/pkgs/development/compilers/llvm/common/clang/default.nix
@@ -24,12 +24,14 @@ let
   pname = "clang";
 
   src' = if monorepoSrc != null then
-    runCommand "${pname}-src-${version}" {} ''
+    runCommand "${pname}-src-${version}" {} (''
       mkdir -p "$out"
+    '' + lib.optionalString (lib.versionAtLeast release_version "14") ''
       cp -r ${monorepoSrc}/cmake "$out"
+    '' + ''
       cp -r ${monorepoSrc}/${pname} "$out"
       cp -r ${monorepoSrc}/clang-tools-extra "$out"
-    '' else src;
+    '') else src;
 
   self = stdenv.mkDerivation (finalAttrs: rec {
     inherit pname version patches;
diff --git a/pkgs/development/compilers/llvm/common/compiler-rt/default.nix b/pkgs/development/compilers/llvm/common/compiler-rt/default.nix
index a6d727739d27..cce348b3ef50 100644
--- a/pkgs/development/compilers/llvm/common/compiler-rt/default.nix
+++ b/pkgs/development/compilers/llvm/common/compiler-rt/default.nix
@@ -47,11 +47,13 @@ let
   pname = baseName + lib.optionalString (haveLibc) "-libc";
 
   src' = if monorepoSrc != null then
-    runCommand "${baseName}-src-${version}" {} ''
+    runCommand "${baseName}-src-${version}" {} (''
       mkdir -p "$out"
+    '' + lib.optionalString (lib.versionAtLeast release_version "14") ''
       cp -r ${monorepoSrc}/cmake "$out"
+    '' + ''
       cp -r ${monorepoSrc}/${baseName} "$out"
-    '' else src;
+    '') else src;
 
   preConfigure = lib.optionalString (!haveLibc) ''
     cmakeFlagsArray+=(-DCMAKE_C_FLAGS="-nodefaultlibs -ffreestanding")
diff --git a/pkgs/development/compilers/llvm/common/default.nix b/pkgs/development/compilers/llvm/common/default.nix
index 55d26de9fc09..2f47f1a583c5 100644
--- a/pkgs/development/compilers/llvm/common/default.nix
+++ b/pkgs/development/compilers/llvm/common/default.nix
@@ -346,13 +346,7 @@ let
   tools = lib.makeExtensible (
     tools:
     let
-      callPackage = newScope (
-        tools
-        // args
-        // metadata
-        # Previously monorepoSrc was erroneously not being passed through.
-        // lib.optionalAttrs (lib.versionOlder metadata.release_version "14") { monorepoSrc = null; } # Preserve a bug during #307211, TODO: remove; causes llvm 13 rebuild.
-      );
+      callPackage = newScope (tools // args // metadata);
       clangVersion =
         if (lib.versionOlder metadata.release_version "16") then
           metadata.release_version
diff --git a/pkgs/development/compilers/llvm/common/libclc.nix b/pkgs/development/compilers/llvm/common/libclc.nix
index 299b27417b6a..c24fc6e3b4c0 100644
--- a/pkgs/development/compilers/llvm/common/libclc.nix
+++ b/pkgs/development/compilers/llvm/common/libclc.nix
@@ -22,11 +22,17 @@ stdenv.mkDerivation rec {
   pname = "libclc";
   inherit version;
 
-  src = runCommand "${pname}-src-${version}" { } ''
-    mkdir -p "$out"
-    cp -r ${monorepoSrc}/cmake "$out"
-    cp -r ${monorepoSrc}/${pname} "$out"
-  '';
+  src = runCommand "${pname}-src-${version}" { } (
+    ''
+      mkdir -p "$out"
+    ''
+    + lib.optionalString (lib.versionAtLeast release_version "14") ''
+      cp -r ${monorepoSrc}/cmake "$out"
+    ''
+    + ''
+      cp -r ${monorepoSrc}/${pname} "$out"
+    ''
+  );
 
   sourceRoot = "${src.name}/${pname}";
 
diff --git a/pkgs/development/compilers/llvm/common/libunwind/default.nix b/pkgs/development/compilers/llvm/common/libunwind/default.nix
index 77854ddfcc5d..63b9737092b8 100644
--- a/pkgs/development/compilers/llvm/common/libunwind/default.nix
+++ b/pkgs/development/compilers/llvm/common/libunwind/default.nix
@@ -19,7 +19,9 @@ let
   src' = if monorepoSrc != null then
     runCommand "${pname}-src-${version}" {} (''
       mkdir -p "$out"
+    '' + lib.optionalString (lib.versionAtLeast release_version "14") ''
       cp -r ${monorepoSrc}/cmake "$out"
+    '' + ''
       cp -r ${monorepoSrc}/${pname} "$out"
       mkdir -p "$out/libcxx"
       cp -r ${monorepoSrc}/libcxx/cmake "$out/libcxx"
diff --git a/pkgs/development/compilers/llvm/common/lld/default.nix b/pkgs/development/compilers/llvm/common/lld/default.nix
index d5c0f7cb3a09..32cf5cb46460 100644
--- a/pkgs/development/compilers/llvm/common/lld/default.nix
+++ b/pkgs/development/compilers/llvm/common/lld/default.nix
@@ -19,21 +19,23 @@ let
   pname = "lld";
   src' =
     if monorepoSrc != null then
-      runCommand "lld-src-${version}" {} ''
+      runCommand "lld-src-${version}" {} (''
         mkdir -p "$out"
+      '' + lib.optionalString (lib.versionAtLeast release_version "14") ''
         cp -r ${monorepoSrc}/cmake "$out"
+      '' + ''
         cp -r ${monorepoSrc}/${pname} "$out"
         mkdir -p "$out/libunwind"
         cp -r ${monorepoSrc}/libunwind/include "$out/libunwind"
         mkdir -p "$out/llvm"
-      '' else src;
+      '') else src;
 
   postPatch = lib.optionalString (lib.versions.major release_version == "12") ''
     substituteInPlace MachO/CMakeLists.txt --replace \
       '(''${LLVM_MAIN_SRC_DIR}/' '('
     mkdir -p libunwind/include
     tar -xf "${libunwind.src}" --wildcards -C libunwind/include --strip-components=2 "libunwind-*/include/"
-  '' + lib.optionalString (lib.versions.major release_version == "13" && stdenv.hostPlatform.isDarwin) ''
+  '' + lib.optionalString (lib.versions.major release_version == "13") ''
     substituteInPlace MachO/CMakeLists.txt --replace \
       '(''${LLVM_MAIN_SRC_DIR}/' '(../'
   '';
@@ -75,4 +77,4 @@ stdenv.mkDerivation (rec {
       of several different linkers.
     '';
   };
-} // (if (postPatch == "" && lib.versions.major release_version != "13") then {} else { inherit postPatch; }))
+} // (lib.optionalAttrs (postPatch != "") { inherit postPatch; }))
diff --git a/pkgs/development/compilers/llvm/common/lldb.nix b/pkgs/development/compilers/llvm/common/lldb.nix
index 4f679f4dcff1..38bc91977c36 100644
--- a/pkgs/development/compilers/llvm/common/lldb.nix
+++ b/pkgs/development/compilers/llvm/common/lldb.nix
@@ -32,7 +32,9 @@ let
     if monorepoSrc != null then
       runCommand "lldb-src-${version}" { } (''
         mkdir -p "$out"
+      '' + lib.optionalString (lib.versionAtLeast release_version "14") ''
         cp -r ${monorepoSrc}/cmake "$out"
+      '' + ''
         cp -r ${monorepoSrc}/lldb "$out"
       '' + lib.optionalString (lib.versionAtLeast release_version "19" && enableManpages) ''
         mkdir -p "$out/llvm"
diff --git a/pkgs/development/compilers/llvm/common/llvm/default.nix b/pkgs/development/compilers/llvm/common/llvm/default.nix
index 281a21ca1524..fc139c703774 100644
--- a/pkgs/development/compilers/llvm/common/llvm/default.nix
+++ b/pkgs/development/compilers/llvm/common/llvm/default.nix
@@ -77,11 +77,15 @@ let
 
   pname = "llvm";
 
+  # TODO: simplify versionAtLeast condition for cmake and third-party via rebuild
   src' = if monorepoSrc != null then
     runCommand "${pname}-src-${version}" {} (''
       mkdir -p "$out"
+    '' + lib.optionalString (lib.versionAtLeast release_version "14") ''
       cp -r ${monorepoSrc}/cmake "$out"
+    '' + ''
       cp -r ${monorepoSrc}/${pname} "$out"
+    '' + lib.optionalString (lib.versionAtLeast release_version "14") ''
       cp -r ${monorepoSrc}/third-party "$out"
     '' + lib.optionalString enablePolly ''
       chmod u+w "$out/${pname}/tools"
diff --git a/pkgs/development/compilers/llvm/common/mlir/default.nix b/pkgs/development/compilers/llvm/common/mlir/default.nix
index e4dd12d69e58..9c3c71c3b705 100644
--- a/pkgs/development/compilers/llvm/common/mlir/default.nix
+++ b/pkgs/development/compilers/llvm/common/mlir/default.nix
@@ -1,6 +1,7 @@
 { lib
 , stdenv
 , llvm_meta
+, release_version
 , buildLlvmTools
 , monorepoSrc
 , runCommand
@@ -18,14 +19,16 @@ stdenv.mkDerivation rec {
   inherit version doCheck;
 
   # Blank llvm dir just so relative path works
-  src = runCommand "${pname}-src-${version}" { } ''
+  src = runCommand "${pname}-src-${version}" { } (''
     mkdir -p "$out"
+  '' + lib.optionalString (lib.versionAtLeast release_version "14") ''
     cp -r ${monorepoSrc}/cmake "$out"
+  '' + ''
     cp -r ${monorepoSrc}/mlir "$out"
     cp -r ${monorepoSrc}/third-party "$out/third-party"
 
     mkdir -p "$out/llvm"
-  '';
+  '');
 
   sourceRoot = "${src.name}/mlir";
 
diff --git a/pkgs/development/compilers/llvm/common/openmp/default.nix b/pkgs/development/compilers/llvm/common/openmp/default.nix
index 57c6de07c784..1ad5948edb86 100644
--- a/pkgs/development/compilers/llvm/common/openmp/default.nix
+++ b/pkgs/development/compilers/llvm/common/openmp/default.nix
@@ -21,11 +21,13 @@ let
   pname = "openmp";
   src' =
     if monorepoSrc != null then
-      runCommand "${pname}-src-${version}" {} ''
+      runCommand "${pname}-src-${version}" {} (''
         mkdir -p "$out"
+      '' + lib.optionalString (lib.versionAtLeast release_version "14") ''
         cp -r ${monorepoSrc}/cmake "$out"
+      '' + ''
         cp -r ${monorepoSrc}/${pname} "$out"
-      '' else src;
+      '') else src;
 in
 stdenv.mkDerivation (rec {
   inherit pname version patches;