Memory usage fixes for Haddock

- Do not include `mi_globals` in the `NoBackend` backend. It was only included
  for Haddock, but Haddock does not actually need it. This causes a 200MB
  reduction in max residency when generating haddocks on the Agda codebase
  (roughly 1GB to 800MB).

- Make haddock_{parser,renamer}_perf tests more accurate by forcing docs to
  be written to interface files using `-fwrite-interface`

Bumps haddock submodule.

Metric Decrease:
    haddock.base

compiler/GHC/Driver/Backend.hs

@@ -551,17 +551,14 @@ backendRespectsSpecialise (Named NoBackend)   = False
 
 -- | This back end wants the `mi_globals` field of a
 -- `ModIface` to be populated (with the top-level bindings
--- of the original source).  True for the interpreter, and
--- also true for "no backend", which is used by Haddock.
--- (After typechecking a module, Haddock wants access to
--- the module's `GlobalRdrEnv`.)
+-- of the original source).  Only true for the interpreter.
 backendWantsGlobalBindings :: Backend -> Bool
 backendWantsGlobalBindings (Named NCG)         = False
 backendWantsGlobalBindings (Named LLVM)        = False
 backendWantsGlobalBindings (Named ViaC)        = False
 backendWantsGlobalBindings (Named JavaScript)  = False
+backendWantsGlobalBindings (Named NoBackend)   = False
 backendWantsGlobalBindings (Named Interpreter) = True
-backendWantsGlobalBindings (Named NoBackend)   = True
 
 -- | The back end targets a technology that implements
 -- `switch` natively.  (For example, LLVM or C.) Therefore

testsuite/tests/haddock/perf/Fold.hs

@@ -143,6 +143,7 @@ import Prelude
 import Data.List.NonEmpty (NonEmpty(..))
 import qualified Data.List.NonEmpty as NonEmpty
 import Control.Monad as Monad
+import Control.Monad.Fix
 import Control.Monad.Reader
 import qualified Control.Monad.Reader as Reader
 import Data.Functor

testsuite/tests/haddock/perf/Makefile

@@ -4,12 +4,12 @@ include $(TOP)/mk/test.mk
 
 # We accept a 5% increase in parser allocations due to -haddock
 haddock_parser_perf :
-	WithHaddock=$(shell '$(TEST_HC)' $(TEST_HC_OPTS) -fno-code -fforce-recomp -Wno-all -ddump-timings -haddock -O0 Fold.hs 2>/dev/null | grep Parser | grep -E -o 'alloc=[0-9]+' | cut -c7-  ) ; \
-	WithoutHaddock=$(shell '$(TEST_HC)' $(TEST_HC_OPTS) -fno-code -fforce-recomp -Wno-all -ddump-timings -O0 Fold.hs 2>/dev/null | grep Parser | grep -E -o 'alloc=[0-9]+' | cut -c7-  ) ;  \
+	WithHaddock=$(shell '$(TEST_HC)' $(TEST_HC_OPTS) -fno-code -fwrite-interface -fforce-recomp -Wno-all -ddump-timings -haddock -O0 Fold.hs 2>/dev/null | grep Parser | grep -E -o 'alloc=[0-9]+' | cut -c7-  ) ; \
+	WithoutHaddock=$(shell '$(TEST_HC)' $(TEST_HC_OPTS) -fno-code -fwrite-interface -fforce-recomp -Wno-all -ddump-timings -O0 Fold.hs 2>/dev/null | grep Parser | grep -E -o 'alloc=[0-9]+' | cut -c7-  ) ;  \
 	  awk "BEGIN { ratio = ($$WithHaddock / $$WithoutHaddock); if (ratio > 1.05) {print \"-haddock allocation ratio too high:\", ratio; exit 1} else {exit 0} }"
 
 # Similarly for the renamer
 haddock_renamer_perf :
-	WithoutHaddock=$(shell '$(TEST_HC)' $(TEST_HC_OPTS) -fno-code -fforce-recomp -Wno-all -ddump-timings -O0 Fold.hs 2>/dev/null | grep Renamer | grep -E -o 'alloc=[0-9]+' | cut -c7-  ) ; \
-	WithHaddock=$(shell '$(TEST_HC)' $(TEST_HC_OPTS) -fno-code -fforce-recomp -Wno-all -ddump-timings -haddock -O0 Fold.hs 2>/dev/null | grep Renamer | grep -E -o 'alloc=[0-9]+' | cut -c7-  ) ;  \
-	  awk "BEGIN { ratio = ($$WithHaddock / $$WithoutHaddock); if (ratio > 1.20) {print \"-haddock allocation ratio too high:\", ratio; exit 1} else {exit 0} }"
+	WithoutHaddock=$(shell '$(TEST_HC)' $(TEST_HC_OPTS) -fno-code -fwrite-interface -fforce-recomp -Wno-all -ddump-timings -O0 Fold.hs 2>/dev/null | grep Renamer | grep -E -o 'alloc=[0-9]+' | cut -c7-  ) ; \
+	WithHaddock=$(shell '$(TEST_HC)' $(TEST_HC_OPTS) -fno-code -fwrite-interface -fforce-recomp -Wno-all -ddump-timings -haddock -O0 Fold.hs 2>/dev/null | grep Renamer | grep -E -o 'alloc=[0-9]+' | cut -c7-  ) ;  \
+	  awk "BEGIN { ratio = ($$WithHaddock / $$WithoutHaddock); if (ratio > 1.05) {print \"-haddock allocation ratio too high:\", ratio; exit 1} else {exit 0} }"

haddock @ 2c6ce806

-Subproject commit 30cf825972c53d97d6add9aa0e61bcb32ccc3ad1
+Subproject commit 2c6ce8063c975602761cf0ae121200fe9c166148