testsuite: check heap profiles readability by hp2ps

This test requires the following locale to be available: fr_FR.utf8

The Haskell part of the program sets LC_ALL to fr_FR, allocates for a
bit to cause one GC, and outputs a number to make use of the locale
it set up earlier.

The Makefile compiles, runs and checks the Haskell program's output;
verifies that we do have all three cases of localized samples in the
.hp file, and runs hp2ps on it.

This ought to ensure:
* libc locales still working as intended on the user's side
* .hp samples are readable to hp2ps

testsuite/tests/profiling/should_run/Makefile

@@ -30,3 +30,15 @@ T15897:
 	"$(TEST_HC)" -prof -fprof-auto -debug -v0 T15897.hs
 	./T15897 10000000 +RTS -s -hc 2>/dev/null
 	./T15897 10000000 +RTS -s -hr 2>/dev/null
+
+.PHONY: T17877-locale
+T17877-locale:
+	"$(HSC2HS)" "$@.hsc"
+	"$(TEST_HC)" $(TEST_HC_OPTS) -rtsopts "$@.hs"
+	"./$@" +RTS -h
+	sed -ne '/BEGIN_SAMPLE/,/END_SAMPLE/ p' "$@.hp" | grep -qv _SAMPLE
+	"$(HP2PS_ABS)" "$@.hp"
+	# In some locales (e.g. mine is fr_FR), printf format sample times as:
+	#   BEGIN_SAMPLE 0,022049
+	# which is unreadable to hp2ps:
+	# hp2ps: prof-locale.hp, line 7, floating point number must follow BEGIN_SAMPLE

testsuite/tests/profiling/should_run/T17877-locale.hsc

+{-# LANGUAGE ForeignFunctionInterface #-}
+
+import Control.Exception
+import Foreign.C.Types
+import Foreign.C.String
+import Foreign.C.Error
+
+#include <locale.h>
+lcAll = #const LC_ALL
+foreign import ccall "locale.h setlocale" c_setlocale :: CInt -> CString -> IO CString
+foreign import ccall  "stdio.h printf"    c_printf :: CString -> CDouble -> IO ()
+
+main = do
+  throwErrnoIfNull "setlocale" $ withCString "fr_FR.utf8" $ c_setlocale lcAll
+
+  -- allocate some junk to get a heap profile
+  s <- getLine
+  evaluate $ last $ scanl1 (+) $ map fromEnum $ concat $ replicate 100000 s
+  -- check 0 (test validity): ensure we got a profile (sed|grep in Makefile)
+
+  -- check 1: RTS doesn't override user's locale setting
+  withCString "%'.3f\n" $ \fmt -> c_printf fmt (read s)
+
+  -- check 2: heap profile is readable by hp2ps (hp2ps in Makefile)

testsuite/tests/profiling/should_run/T17877-locale.stdin

+3141.592653589793

testsuite/tests/profiling/should_run/T17877-locale.stdout

+[1 of 1] Compiling Main             ( T17877-locale.hs, T17877-locale.o )
+Linking T17877-locale ...
+3 141,593

testsuite/tests/profiling/should_run/all.T

@@ -151,3 +151,5 @@ test('T15897',
      makefile_test, ['T15897'])
 
 test('T17572', [], compile_and_run, [''])
+
+test('T17877-locale', normal, makefile_test, [])