diff --git a/pkgs/development/compilers/gcc/common/configure-flags.nix b/pkgs/development/compilers/gcc/common/configure-flags.nix index f38ce180b1f0..0560fe0fda80 100644 --- a/pkgs/development/compilers/gcc/common/configure-flags.nix +++ b/pkgs/development/compilers/gcc/common/configure-flags.nix @@ -27,6 +27,16 @@ assert cloog != null -> stdenv.lib.versionOlder version "5"; assert langJava -> stdenv.lib.versionOlder version "7"; +# Note [Windows Exception Handling] +# sjlj (short jump long jump) exception handling makes no sense on x86_64, +# it's forcably slowing programs down as it produces a constant overhead. +# On x86_64 we have SEH (Structured Exception Handling) and we should use +# that. On i686, we do not have SEH, and have to use sjlj with dwarf2. +# Hence it's now conditional on x86_32 (i686 is 32bit). +# +# ref: https://stackoverflow.com/questions/15670169/what-is-difference-between-sjlj-vs-dwarf-vs-seh + + let inherit (stdenv) buildPlatform hostPlatform targetPlatform @@ -60,7 +70,9 @@ let "--disable-debug" "--disable-win32-registry" ] ++ lib.optionals (crossMingw && targetPlatform.isx86_32) [ + # See Note [Windows Exception Handling] "--enable-sjlj-exceptions" + "--with-dwarf2" ] else [ (if crossDarwin then "--with-sysroot=${lib.getLib libcCross}/share/sysroot" else "--with-headers=${lib.getDev libcCross}${libcCross.incdir or "/include"}") @@ -87,9 +99,6 @@ let "--disable-nls" # To keep ABI compatibility with upstream mingw-w64 "--enable-fully-dynamic-string" - ] ++ lib.optionals (crossMingw && targetPlatform.isx86_32) [ - "--enable-sjlj-exceptions" - "--with-dwarf2" ] ++ lib.optional (targetPlatform.libc == "newlib") "--with-newlib" ++ lib.optional (targetPlatform.libc == "avrlibc") "--with-avrlibc" );