testsuite: allow accepting of fine grained results [skip ci]

Summary:
Sometimes we need to be able to mass accept changes that are platform
specific and that can't be normalized away using our string formatters.

e.g. differences in I/O manager errors or behaviors. This allows one
to do so easier than before and less error prone.

I have updated the docs and made it clear this should only be used
when a normalizer won't work:

https://ghc.haskell.org/trac/ghc/wiki/Building/RunningTests/Updating

Test Plan: Manually tested while working on new I/O manager

Reviewers: bgamari

Subscribers: thomie, carter

Differential Revision: https://phabricator.haskell.org/D4549

3 files changed, 30 insertions, 6 deletions

diff --git a/testsuite/driver/testglobals.py b/testsuite/driver/testglobals.py
index 44fe125dc5..f6831c9ad8 100644
--- a/testsuite/driver/testglobals.py
+++ b/testsuite/driver/testglobals.py
@@ -1,4 +1,4 @@
-# 
+#
 # (c) Simon Marlow 2002
 #
 
@@ -9,7 +9,7 @@
 # variable config below.  The fields of the structure are filled in by
 # the appropriate config script(s) for this compiler/platform, in
 # ../config.
-# 
+#
 # Bits of the structure may also be filled in from the command line,
 # via the build system, using the '-e' option to runtests.
 
@@ -28,6 +28,8 @@ class TestConfig:
 
         # Accept new output which differs from the sample?
         self.accept = 0
+        self.accept_platform = 0
+        self.accept_os = 0
 
         # File in which to save the summary
         self.summary_file = ''
@@ -70,7 +72,7 @@ class TestConfig:
 
         # Flags we always give to this compiler
         self.compiler_always_flags = []
-        
+
         # Which ways to run tests (when compiling and running respectively)
         # Other ways are added from the command line if we have the appropriate
         # libraries.
@@ -109,7 +111,7 @@ class TestConfig:
         # the timeout program
         self.timeout_prog = ''
         self.timeout = 300
-        
+
         # threads
         self.threads = 1
         self.use_threads = 0
diff --git a/testsuite/driver/testlib.py b/testsuite/driver/testlib.py
index 8bdbedfdcd..f2bb1c9f01 100644
--- a/testsuite/driver/testlib.py
+++ b/testsuite/driver/testlib.py
@@ -1597,7 +1597,17 @@ def compare_outputs(way, kind, normaliser, expected_file, actual_file,
             if_verbose(1, 'Test is expected to fail. Not accepting new output.')
             return 0
         elif config.accept and actual_raw:
-            if_verbose(1, 'Accepting new output.')
+            if config.accept_platform:
+                if_verbose(1, 'Accepting new output for platform "'
+                              + config.platform + '".')
+                expected_path += '-' + config.platform
+            elif config.accept_os:
+                if_verbose(1, 'Accepting new output for os "'
+                              + config.os + '".')
+                expected_path += '-' + config.os
+            else:
+                if_verbose(1, 'Accepting new output.')
+
             write_file(expected_path, actual_raw)
             return 1
         elif config.accept:
@@ -1914,7 +1924,7 @@ def in_srcdir(name, suffix=''):
 
 # Finding the sample output.  The filename is of the form
 #
-#   <test>.stdout[-ws-<wordsize>][-<platform>]
+#   <test>.stdout[-ws-<wordsize>][-<platform>|-<os>]
 #
 def find_expected_file(name, suff):
     basename = add_suffix(name, suff)
diff --git a/testsuite/mk/test.mk b/testsuite/mk/test.mk
index a21c4bb16b..1eb8d49c4b 100644
--- a/testsuite/mk/test.mk
+++ b/testsuite/mk/test.mk
@@ -14,6 +14,9 @@
 #  CONFIG    -- use a different configuration file
 #  COMPILER  -- select a configuration file from config/
 #  THREADS   -- run n tests at once
+#  PLATFORM  -- if accepting a result, accept it for the current platform.
+#  OS        -- if accepting a result, accept it for all wordsizes of the
+#               current os.
 #
 # -----------------------------------------------------------------------------
 
@@ -280,6 +283,15 @@ endif
 
 ifeq "$(accept)" "YES"
 setaccept = -e config.accept=1
+
+ifeq "$(PLATFORM)" "YES"
+setaccept += -e config.accept_platform=1
+endif
+
+ifeq "$(OS)" "YES"
+setaccept += -e config.accept_os=1
+endif
+
 else
 setaccept =
 endif