12 files changed, 58 insertions, 12 deletions
diff --git a/pkgs/development/compilers/llvm/10/default.nix b/pkgs/development/compilers/llvm/10/default.nix
index 8bd7e937e7d72..83840b4fd27ea 100644
--- a/pkgs/development/compilers/llvm/10/default.nix
+++ b/pkgs/development/compilers/llvm/10/default.nix
@@ -89,7 +89,11 @@ let
     #   python3 = pkgs.python3;  # don't use python-boot
     # });
 
-    clang = if stdenv.cc.isGNU then tools.libstdcxxClang else tools.libcxxClang;
+    # pick clang appropriate for package set we are targeting
+    clang =
+      if (pkgs.targetPackages.stdenv or stdenv).cc.isGNU
+      then tools.libstdcxxClang
+      else tools.libcxxClang;
 
     libstdcxxClang = wrapCCWith rec {
       cc = tools.clang-unwrapped;
diff --git a/pkgs/development/compilers/llvm/11/default.nix b/pkgs/development/compilers/llvm/11/default.nix
index ebd0dc672aa35..b5c0709152428 100644
--- a/pkgs/development/compilers/llvm/11/default.nix
+++ b/pkgs/development/compilers/llvm/11/default.nix
@@ -104,7 +104,11 @@ let
     #   python3 = pkgs.python3;  # don't use python-boot
     # });
 
-    clang = if stdenv.cc.isGNU then tools.libstdcxxClang else tools.libcxxClang;
+    # pick clang appropriate for package set we are targeting
+    clang =
+      if (pkgs.targetPackages.stdenv or stdenv).cc.isGNU
+      then tools.libstdcxxClang
+      else tools.libcxxClang;
 
     libstdcxxClang = wrapCCWith rec {
       cc = tools.clang-unwrapped;
diff --git a/pkgs/development/compilers/llvm/12/default.nix b/pkgs/development/compilers/llvm/12/default.nix
index e68522faea06c..8de6bb420d41e 100644
--- a/pkgs/development/compilers/llvm/12/default.nix
+++ b/pkgs/development/compilers/llvm/12/default.nix
@@ -92,7 +92,11 @@ let
     #   python3 = pkgs.python3;  # don't use python-boot
     # });
 
-    clang = if stdenv.cc.isGNU then tools.libstdcxxClang else tools.libcxxClang;
+    # pick clang appropriate for package set we are targeting
+    clang =
+      if (pkgs.targetPackages.stdenv or stdenv).cc.isGNU
+      then tools.libstdcxxClang
+      else tools.libcxxClang;
 
     libstdcxxClang = wrapCCWith rec {
       cc = tools.clang-unwrapped;
diff --git a/pkgs/development/compilers/llvm/13/default.nix b/pkgs/development/compilers/llvm/13/default.nix
index a89c6dabe3912..bdc07a68742d5 100644
--- a/pkgs/development/compilers/llvm/13/default.nix
+++ b/pkgs/development/compilers/llvm/13/default.nix
@@ -93,7 +93,11 @@ let
     #   python3 = pkgs.python3;  # don't use python-boot
     # });
 
-    clang = if stdenv.cc.isGNU then tools.libstdcxxClang else tools.libcxxClang;
+    # pick clang appropriate for package set we are targeting
+    clang =
+      if (pkgs.targetPackages.stdenv or stdenv).cc.isGNU
+      then tools.libstdcxxClang
+      else tools.libcxxClang;
 
     libstdcxxClang = wrapCCWith rec {
       cc = tools.clang-unwrapped;
diff --git a/pkgs/development/compilers/llvm/5/default.nix b/pkgs/development/compilers/llvm/5/default.nix
index 4593580b72fda..4a6d55d55727f 100644
--- a/pkgs/development/compilers/llvm/5/default.nix
+++ b/pkgs/development/compilers/llvm/5/default.nix
@@ -65,7 +65,11 @@ let
       python3 = pkgs.python3;  # don't use python-boot
     });
 
-    clang = if stdenv.cc.isGNU then tools.libstdcxxClang else tools.libcxxClang;
+    # pick clang appropriate for package set we are targeting
+    clang =
+      if (pkgs.targetPackages.stdenv or stdenv).cc.isGNU
+      then tools.libstdcxxClang
+      else tools.libcxxClang;
 
     libstdcxxClang = wrapCCWith rec {
       cc = tools.clang-unwrapped;
diff --git a/pkgs/development/compilers/llvm/6/default.nix b/pkgs/development/compilers/llvm/6/default.nix
index 9b1caf410bc26..1b9a793e8858b 100644
--- a/pkgs/development/compilers/llvm/6/default.nix
+++ b/pkgs/development/compilers/llvm/6/default.nix
@@ -66,7 +66,11 @@ let
       python3 = pkgs.python3;  # don't use python-boot
     });
 
-    clang = if stdenv.cc.isGNU then tools.libstdcxxClang else tools.libcxxClang;
+    # pick clang appropriate for package set we are targeting
+    clang =
+      if (pkgs.targetPackages.stdenv or stdenv).cc.isGNU
+      then tools.libstdcxxClang
+      else tools.libcxxClang;
 
     libstdcxxClang = wrapCCWith rec {
       cc = tools.clang-unwrapped;
diff --git a/pkgs/development/compilers/llvm/7/default.nix b/pkgs/development/compilers/llvm/7/default.nix
index d014c043a80db..841fc120d7445 100644
--- a/pkgs/development/compilers/llvm/7/default.nix
+++ b/pkgs/development/compilers/llvm/7/default.nix
@@ -96,7 +96,11 @@ let
       python3 = pkgs.python3;  # don't use python-boot
     });
 
-    clang = if stdenv.cc.isGNU then tools.libstdcxxClang else tools.libcxxClang;
+    # pick clang appropriate for package set we are targeting
+    clang =
+      if (pkgs.targetPackages.stdenv or stdenv).cc.isGNU
+      then tools.libstdcxxClang
+      else tools.libcxxClang;
 
     libstdcxxClang = wrapCCWith rec {
       cc = tools.clang-unwrapped;
diff --git a/pkgs/development/compilers/llvm/8/default.nix b/pkgs/development/compilers/llvm/8/default.nix
index 7252b75a33974..234473c1adaee 100644
--- a/pkgs/development/compilers/llvm/8/default.nix
+++ b/pkgs/development/compilers/llvm/8/default.nix
@@ -97,7 +97,11 @@ let
       python3 = pkgs.python3;  # don't use python-boot
     });
 
-    clang = if stdenv.cc.isGNU then tools.libstdcxxClang else tools.libcxxClang;
+    # pick clang appropriate for package set we are targeting
+    clang =
+      if (pkgs.targetPackages.stdenv or stdenv).cc.isGNU
+      then tools.libstdcxxClang
+      else tools.libcxxClang;
 
     libstdcxxClang = wrapCCWith rec {
       cc = tools.clang-unwrapped;
diff --git a/pkgs/development/compilers/llvm/9/default.nix b/pkgs/development/compilers/llvm/9/default.nix
index 9126a614b106b..a10bac13824ed 100644
--- a/pkgs/development/compilers/llvm/9/default.nix
+++ b/pkgs/development/compilers/llvm/9/default.nix
@@ -97,7 +97,11 @@ let
       python3 = pkgs.python3;  # don't use python-boot
     });
 
-    clang = if stdenv.cc.isGNU then tools.libstdcxxClang else tools.libcxxClang;
+    # pick clang appropriate for package set we are targeting
+    clang =
+      if (pkgs.targetPackages.stdenv or stdenv).cc.isGNU
+      then tools.libstdcxxClang
+      else tools.libcxxClang;
 
     libstdcxxClang = wrapCCWith rec {
       cc = tools.clang-unwrapped;
diff --git a/pkgs/development/compilers/llvm/git/default.nix b/pkgs/development/compilers/llvm/git/default.nix
index 666e9be3cd89e..56904addb52b1 100644
--- a/pkgs/development/compilers/llvm/git/default.nix
+++ b/pkgs/development/compilers/llvm/git/default.nix
@@ -93,7 +93,11 @@ let
     #   python3 = pkgs.python3;  # don't use python-boot
     # });
 
-    clang = if stdenv.cc.isGNU then tools.libstdcxxClang else tools.libcxxClang;
+    # pick clang appropriate for package set we are targeting
+    clang =
+      if (pkgs.targetPackages.stdenv or stdenv).cc.isGNU
+      then tools.libstdcxxClang
+      else tools.libcxxClang;
 
     libstdcxxClang = wrapCCWith rec {
       cc = tools.clang-unwrapped;
diff --git a/pkgs/stdenv/booter.nix b/pkgs/stdenv/booter.nix
index 51d617354e869..f1d07e6461a9c 100644
--- a/pkgs/stdenv/booter.nix
+++ b/pkgs/stdenv/booter.nix
@@ -124,7 +124,13 @@ stageFuns: let
       if buildPackages.stdenv.hasCC
       then
         if buildPackages.stdenv.cc.isClang or false
-        then buildPackages.clang
+        # buildPackages.clang checks targetPackages.stdenv.cc (i. e. this
+        # attribute) to get a sense of the its set's default compiler and
+        # chooses between libc++ and libstdc++ based on that. If we hit this
+        # code here, we'll cause an infinite recursion. Since a set with
+        # clang as its default compiler always means libc++, we can infer this
+        # decision statically.
+        then buildPackages.llvmPackages.libcxxClang
         else buildPackages.gcc
       else
         # This will blow up if anything uses it, but that's OK. The `if
diff --git a/pkgs/stdenv/cross/default.nix b/pkgs/stdenv/cross/default.nix
index 613b8d5304c01..e01ac74599aeb 100644
--- a/pkgs/stdenv/cross/default.nix
+++ b/pkgs/stdenv/cross/default.nix
@@ -70,7 +70,7 @@ in lib.init bootStages ++ [
              # when there is a C compiler and everything should be fine.
              then throw "no C compiler provided for this platform"
            else if crossSystem.isDarwin
-             then buildPackages.llvmPackages.clang
+             then buildPackages.llvmPackages.libcxxClang
            else if crossSystem.useLLVM or false
              then buildPackages.llvmPackages.clangUseLLVM
            else buildPackages.gcc;