Make sure GCC uses the Sparc V9 instruction set

We only support Sparc V9 and better as V8 lacks an atomic CAS instruction
which we need for SMP. This means that we have to pass -mcpu=v9 to GCC when
compiling and assembling. Hardcoding the flag is hackish but seems to be
our best bet at the moment. It can still be overridden by the user as GCC
picks the best -mcpu flag regardless of the ordering.

diff --git a/compiler/main/DriverPipeline.hs b/compiler/main/DriverPipeline.hs
index e8f64e8..58cc49e 100644 (file)
--- a/compiler/main/DriverPipeline.hs
+++ b/compiler/main/DriverPipeline.hs
@@ -859,6 +859,15 @@ runPhase cc_phase stop dflags basename suff input_fn get_output_fn maybe_loc
                       ++ map SysTools.Option (
                          md_c_flags
                        ++ pic_c_flags
+#ifdef sparc_TARGET_ARCH
+        -- We only support SparcV9 and better because V8 lacks an atomic CAS
+        -- instruction. Note that the user can still override this
+       -- (e.g., -mcpu=ultrasparc) as GCC picks the "best" -mcpu flag
+       -- regardless of the ordering.
+        --
+        -- This is a temporary hack.
+                       ++ ["-mcpu=v9"]
+#endif
                       ++ (if hcc && mangle
                             then md_regd_c_flags
                             else [])
@@ -946,6 +955,16 @@ runPhase As stop dflags _basename _suff input_fn get_output_fn maybe_loc
        SysTools.runAs dflags   
                       (map SysTools.Option as_opts
                       ++ [ SysTools.Option ("-I" ++ p) | p <- cmdline_include_paths ]
+#ifdef sparc_TARGET_ARCH
+        -- We only support SparcV9 and better because V8 lacks an atomic CAS
+       -- instruction so we have to make sure that the assembler accepts the
+        -- instruction set. Note that the user can still override this
+       -- (e.g., -mcpu=ultrasparc). GCC picks the "best" -mcpu flag
+       -- regardless of the ordering.
+       --
+       -- This is a temporary hack.
+                      ++ [ SysTools.Option "-mcpu=v9" ]
+#endif
                       ++ [ SysTools.Option "-c"
                          , SysTools.FileOption "" input_fn
                          , SysTools.Option "-o"