Consolidate `TablesNextToCode` and `GhcUnreigsterised` in configure (#15548)

`TablesNextToCode` is now a substituted by configure, where it has the
correct defaults and error handling. Nowhere else needs to duplicate
that, though we may want the compiler to to guard against bogus settings
files.

I renamed it from `GhcEnableTablesNextToCode` to `TablesNextToCode` to:

 - Help me guard against any unfixed usages

 - Remove any lingering connotation that this flag needs to be combined
   with `GhcUnreigsterised`.

Original reviewers:

Original subscribers: TerrorJack, rwbarton, carter

Original Differential Revision: https://phabricator.haskell.org/D5082

13 files changed, 78 insertions, 43 deletions

diff --git a/compiler/ghc.mk b/compiler/ghc.mk
index 629a1ed..441b698 100644
--- a/compiler/ghc.mk
+++ b/compiler/ghc.mk
@@ -256,7 +256,7 @@ endif
 ifeq "$(GhcWithInterpreter)" "YES"
 compiler_stage2_CONFIGURE_OPTS += --flags=ghci
 
-ifeq "$(GhcEnableTablesNextToCode) $(GhcUnregisterised)" "YES NO"
+ifeq "$(TablesNextToCode)" "YES"
 # Should GHCI be building info tables in the TABLES_NEXT_TO_CODE style
 # or not?
 # XXX This should logically be a CPP option, but there doesn't seem to
diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index ca53fda..fe7e313 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -59,7 +59,6 @@ module DynFlags (
         fFlags, fLangFlags, xFlags,
         wWarningFlags,
         dynFlagDependencies,
-        tablesNextToCode,
         makeDynFlagsConsistent,
         shouldUseColor,
         shouldUseHexWordLiterals,
@@ -159,6 +158,7 @@ module DynFlags (
         opt_L, opt_P, opt_F, opt_c, opt_cxx, opt_a, opt_l, opt_i,
         opt_P_signature,
         opt_windres, opt_lo, opt_lc, opt_lcc,
+        tablesNextToCode,
 
         -- ** Manipulating DynFlags
         addPluginModuleName,
@@ -1493,6 +1493,9 @@ opt_lc dflags= toolSettings_opt_lc $ toolSettings dflags
 opt_i                 :: DynFlags -> [String]
 opt_i dflags= toolSettings_opt_i $ toolSettings dflags
 
+tablesNextToCode :: DynFlags -> Bool
+tablesNextToCode = platformMisc_tablesNextToCode . platformMisc
+
 -- | The directory for this version of ghc in the user's app directory
 -- (typically something like @~/.ghc/x86_64-linux-7.6.3@)
 --
@@ -1664,15 +1667,6 @@ defaultObjectTarget dflags = defaultHscTarget
   (targetPlatform dflags)
   (platformMisc dflags)
 
--- Determines whether we will be compiling
--- info tables that reside just before the entry code, or with an
--- indirection to the entry code.  See TABLES_NEXT_TO_CODE in
--- includes/rts/storage/InfoTables.h.
-tablesNextToCode :: DynFlags -> Bool
-tablesNextToCode dflags =
-    not (platformUnregisterised $ targetPlatform dflags) &&
-    platformMisc_tablesNextToCode (platformMisc dflags)
-
 data DynLibLoader
   = Deployable
   | SystemDependent
diff --git a/configure.ac b/configure.ac
index aa48872..0524d14 100644
--- a/configure.ac
+++ b/configure.ac
@@ -271,6 +271,55 @@ AC_ARG_ENABLE(unregisterised,
 )
 AC_SUBST(Unregisterised)
 
+dnl ** Do a build with tables next to code?
+dnl
+dnl Whether the target architecture supports placing info tables
+dnl directly before the entry code (see TABLES_NEXT_TO_CODE in the RTS).
+dnl Whether we actually compile for TABLES_NEXT_TO_CODE depends on
+dnl whether we're building unregisterised code or not, which may be
+dnl decided by options to the compiler later.
+dnl
+dnl See https://gitlab.haskell.org/ghc/ghc/wikis/commentary/rts/storage/heap-objects#tables_next_to_code
+dnl --------------------------------------------------------------
+case "$Unregisterised" in
+    NO)
+        case "$TargetArch" in
+            ia64|powerpc64|powerpc64le)
+                TablesNextToCodeDefault=NO
+                ;;
+            *)
+                TablesNextToCodeDefault=YES
+                ;;
+        esac
+        ;;
+    YES)
+        TablesNextToCodeDefault=NO
+        ;;
+esac
+AC_ARG_ENABLE(tables-next-to-code,
+[AC_HELP_STRING([--enable-tables-next-to-code],
+[Build an tables-next-to-code compiler (enabled by default on platforms without registerised support) [default="$TablesNextToCodeDefault"]])],
+[ if test x"$enableval" = x"yes"; then
+        TablesNextToCode=YES
+  else
+        TablesNextToCode=NO
+  fi
+],
+[TablesNextToCode="$TablesNextToCodeDefault"]
+)
+
+fail() {
+    echo >&2
+    echo "$1" >&2
+    exit 1
+}
+
+if test "$TablesNextToCodeDefault" = "NO" && test "$TablesNextToCode" = "YES"; then
+    fail "Error: tables next to code was requested but is not supported"
+fi
+
+AC_SUBST(TablesNextToCode)
+
 dnl ** Does target have runtime linker support?
 dnl --------------------------------------------------------------
 case "$target" in
@@ -286,12 +335,6 @@ AC_SUBST(HaskellHaveRTSLinker)
 # Requires FPTOOLS_SET_PLATFORM_VARS to be run first.
 FP_FIND_ROOT
 
-fail() {
-    echo >&2
-    echo "$1" >&2
-    exit 1
-}
-
 
 if test "$HostOS" = "mingw32"
 then
@@ -1335,6 +1378,7 @@ echo "\
       which is version       : $GccVersion
    Building a cross compiler : $CrossCompiling
    Unregisterised            : $Unregisterised
+   TablesNextToCode          : $TablesNextToCode
    hs-cpp       : $HaskellCPPCmd
    hs-cpp-flags : $HaskellCPPArgs
    ar           : $ArCmd
diff --git a/hadrian/cfg/system.config.in b/hadrian/cfg/system.config.in
index 5bdb322..2380baf 100644
--- a/hadrian/cfg/system.config.in
+++ b/hadrian/cfg/system.config.in
@@ -43,6 +43,7 @@ hs-cpp-args         = @HaskellCPPArgs@
 
 solaris-broken-shld  = @SOLARIS_BROKEN_SHLD@
 ghc-unregisterised   = @Unregisterised@
+tables-next-to-code  = @TablesNextToCode@
 ghc-source-path      = @hardtop@
 leading-underscore   = @LeadingUnderscore@
 
diff --git a/hadrian/src/Oracles/Flag.hs b/hadrian/src/Oracles/Flag.hs
index 4f5116b..075a1bf 100644
--- a/hadrian/src/Oracles/Flag.hs
+++ b/hadrian/src/Oracles/Flag.hs
@@ -13,6 +13,7 @@ data Flag = ArSupportsAtFile
           | CrossCompiling
           | GccIsClang
           | GhcUnregisterised
+          | TablesNextToCode
           | GmpInTree
           | GmpFrameworkPref
           | LeadingUnderscore
@@ -30,6 +31,7 @@ flag f = do
             CrossCompiling     -> "cross-compiling"
             GccIsClang         -> "gcc-is-clang"
             GhcUnregisterised  -> "ghc-unregisterised"
+            TablesNextToCode   -> "tables-next-to-code"
             GmpInTree          -> "intree-gmp"
             GmpFrameworkPref   -> "gmp-framework-preferred"
             LeadingUnderscore  -> "leading-underscore"
diff --git a/hadrian/src/Oracles/Setting.hs b/hadrian/src/Oracles/Setting.hs
index 408f9e3..51ccc72 100644
--- a/hadrian/src/Oracles/Setting.hs
+++ b/hadrian/src/Oracles/Setting.hs
@@ -1,7 +1,7 @@
 module Oracles.Setting (
     configFile, Setting (..), SettingList (..), setting, settingList, getSetting,
     getSettingList,  anyTargetPlatform, anyTargetOs, anyTargetArch, anyHostOs,
-    ghcWithInterpreter, ghcEnableTablesNextToCode, useLibFFIForAdjustors,
+    ghcWithInterpreter, useLibFFIForAdjustors,
     ghcCanonVersion, cmdLineLengthLimit, hostSupportsRPaths, topDirectory,
     libsuf, ghcVersionStage, SettingsFileSetting (..), settingsFileSetting
     ) where
@@ -225,11 +225,6 @@ ghcWithInterpreter = do
                               , "sparc64", "arm" ]
     return $ goodOs && goodArch
 
--- | Check whether the target architecture supports placing info tables next to
--- code. See: https://gitlab.haskell.org/ghc/ghc/wikis/commentary/rts/storage/heap-objects#tables_next_to_code.
-ghcEnableTablesNextToCode :: Action Bool
-ghcEnableTablesNextToCode = notM $ anyTargetArch ["ia64", "powerpc64", "powerpc64le"]
-
 -- | Check to use @libffi@ for adjustors.
 useLibFFIForAdjustors :: Action Bool
 useLibFFIForAdjustors = notM $ anyTargetArch ["i386", "x86_64"]
diff --git a/hadrian/src/Rules/Generate.hs b/hadrian/src/Rules/Generate.hs
index 18e6f92..8ad8ead 100644
--- a/hadrian/src/Rules/Generate.hs
+++ b/hadrian/src/Rules/Generate.hs
@@ -313,7 +313,7 @@ generateSettings = do
         , ("Use native code generator", expr $ yesNo <$> ghcWithNativeCodeGen)
         , ("Support SMP", expr $ yesNo <$> ghcWithSMP)
         , ("RTS ways", unwords . map show <$> getRtsWays)
-        , ("Tables next to code", expr $ yesNo <$> ghcEnableTablesNextToCode)
+        , ("Tables next to code", expr $ yesNo <$> flag TablesNextToCode)
         , ("Leading underscore", expr $ yesNo <$> flag LeadingUnderscore)
         , ("Use LibFFI", expr $ yesNo <$> useLibFFIForAdjustors)
         , ("Use Threads", yesNo . any (wayUnit Threaded) <$> getRtsWays)
@@ -373,7 +373,7 @@ generateGhcAutoconfH :: Expr String
 generateGhcAutoconfH = do
     trackGenerateHs
     configHContents  <- expr $ map undefinePackage <$> readFileLines configH
-    tablesNextToCode <- expr ghcEnableTablesNextToCode
+    tablesNextToCode <- getFlag    TablesNextToCode
     ghcUnreg         <- getFlag    GhcUnregisterised
     ccLlvmBackend    <- getSetting CcLlvmBackend
     ccClangBackend   <- getSetting CcClangBackend
diff --git a/hadrian/src/Settings/Packages.hs b/hadrian/src/Settings/Packages.hs
index ecffc58..01c170b 100644
--- a/hadrian/src/Settings/Packages.hs
+++ b/hadrian/src/Settings/Packages.hs
@@ -67,7 +67,7 @@ packageArgs = do
             , (any (wayUnit Threaded) rtsWays) ?
               notStage0 ? arg "--ghc-option=-optc-DTHREADED_RTS"
             , ghcWithInterpreter ?
-              ghcEnableTablesNextToCode ?
+              flag TablesNextToCode ?
               notM (flag GhcUnregisterised) ?
               notStage0 ? arg "--ghc-option=-DGHCI_TABLES_NEXT_TO_CODE"
             , ghcWithInterpreter ?
@@ -196,7 +196,7 @@ rtsPackageArgs = package rts ? do
     targetOs       <- getSetting TargetOs
     targetVendor   <- getSetting TargetVendor
     ghcUnreg       <- expr $ yesNo <$> flag GhcUnregisterised
-    ghcEnableTNC   <- expr $ yesNo <$> ghcEnableTablesNextToCode
+    ghcEnableTNC   <- expr $ yesNo <$> flag TablesNextToCode
     rtsWays        <- getRtsWays
     way            <- getWay
     path           <- getBuildPath
@@ -249,7 +249,8 @@ rtsPackageArgs = package rts ? do
             , "-DTargetOS="                  ++ show targetOs
             , "-DTargetVendor="              ++ show targetVendor
             , "-DGhcUnregisterised="         ++ show ghcUnreg
-            , "-DGhcEnableTablesNextToCode=" ++ show ghcEnableTNC ]
+            , "-DTablesNextToCode="          ++ show ghcEnableTNC
+            ]
 
           -- We're after pur performance here. So make sure fast math and
           -- vectorization is enabled.
diff --git a/includes/ghc.mk b/includes/ghc.mk
index 7ad63ba..ad51234 100644
--- a/includes/ghc.mk
+++ b/includes/ghc.mk
@@ -102,7 +102,7 @@ $(includes_H_CONFIG) : mk/config.h mk/config.mk includes/ghc.mk | $$(dir $$@)/.
 #
 #	Tack on some extra config information from the build system
 #
-ifeq "$(GhcEnableTablesNextToCode) $(GhcUnregisterised)" "YES NO"
+ifeq "$(TablesNextToCode)" "YES"
 	@echo >> $@
 	@echo "#define TABLES_NEXT_TO_CODE 1" >> $@
 endif
@@ -211,7 +211,7 @@ $(includes_SETTINGS) : includes/Makefile | $$(dir $$@)/.
 	@echo ',("Use native code generator", "$(GhcWithNativeCodeGen)")' >> $@
 	@echo ',("Support SMP", "$(GhcWithSMP)")' >> $@
 	@echo ',("RTS ways", "$(GhcRTSWays)")' >> $@
-	@echo ',("Tables next to code", "$(GhcEnableTablesNextToCode)")' >> $@
+	@echo ',("Tables next to code", "$(TablesNextToCode)")' >> $@
 	@echo ',("Leading underscore", "$(LeadingUnderscore)")' >> $@
 	@echo ',("Use LibFFI", "$(UseLibFFIForAdjustors)")' >> $@
 # Note that GhcThreaded just reflects the Makefile variable setting. In
diff --git a/libraries/ghc-boot/GHC/Platform.hs b/libraries/ghc-boot/GHC/Platform.hs
index ea1aa5e..7eec31a 100644
--- a/libraries/ghc-boot/GHC/Platform.hs
+++ b/libraries/ghc-boot/GHC/Platform.hs
@@ -269,6 +269,9 @@ data PlatformMisc = PlatformMisc
   , platformMisc_ghcWithNativeCodeGen :: Bool
   , platformMisc_ghcWithSMP           :: Bool
   , platformMisc_ghcRTSWays           :: String
+  -- | Determines whether we will be compiling info tables that reside just
+  --   before the entry code, or with an indirection to the entry code. See
+  --   TABLES_NEXT_TO_CODE in includes/rts/storage/InfoTables.h.
   , platformMisc_tablesNextToCode     :: Bool
   , platformMisc_leadingUnderscore    :: Bool
   , platformMisc_libFFI               :: Bool
diff --git a/mk/config.mk.in b/mk/config.mk.in
index 10326d0..ca17e86 100644
--- a/mk/config.mk.in
+++ b/mk/config.mk.in
@@ -211,17 +211,6 @@ else
 GhcWithInterpreter=$(if $(findstring YES,$(DYNAMIC_GHC_PROGRAMS)),YES,NO)
 endif
 
-# GhcEnableTablesNextToCode tells us whether the target architecture
-# supports placing info tables directly before the entry code
-# (see TABLES_NEXT_TO_CODE in the RTS).  Whether we actually compile for
-# TABLES_NEXT_TO_CODE depends on whether we're building unregisterised
-# code or not, which may be decided by options to the compiler later.
-ifneq "$(findstring $(TargetArch_CPP)X, ia64X powerpc64X powerpc64leX)" ""
-GhcEnableTablesNextToCode=NO
-else
-GhcEnableTablesNextToCode=YES
-endif
-
 # Whether to use libffi for adjustors (foreign import "wrapper") or
 # not.  If we have built-in support (rts/Adjustor.c) then we use that,
 # otherwise we fall back on libffi, which is slightly slower.
@@ -505,6 +494,7 @@ HaskellHaveIdentDirective = @HaskellHaveIdentDirective@
 HaskellHaveSubsectionsViaSymbols = @HaskellHaveSubsectionsViaSymbols@
 HaskellHaveRTSLinker = @HaskellHaveRTSLinker@
 Unregisterised = @Unregisterised@
+TablesNextToCode = @TablesNextToCode@
 
 SettingsCCompilerCommand = @SettingsCCompilerCommand@
 SettingsHaskellCPPCommand = @SettingsHaskellCPPCommand@
diff --git a/rts/RtsUtils.c b/rts/RtsUtils.c
index b099fa2..2a53d18 100644
--- a/rts/RtsUtils.c
+++ b/rts/RtsUtils.c
@@ -304,8 +304,13 @@ void printRtsInfo(const RtsConfig rts_config) {
     mkRtsInfoPair("Target OS",               TargetOS);
     mkRtsInfoPair("Target vendor",           TargetVendor);
     mkRtsInfoPair("Word size",               TOSTRING(WORD_SIZE_IN_BITS));
+    // TODO(@Ericson2314) This is a joint property of the RTS and generated
+    // code. The compiler will soon be multi-target so it doesn't make sense to
+    // say the target is <ABI adj>, unless we are talking about the host
+    // platform of the compiler / ABI used by a compiler plugin. This is *not*
+    // that, so I think a rename is in order to avoid confusion.
     mkRtsInfoPair("Compiler unregisterised", GhcUnregisterised);
-    mkRtsInfoPair("Tables next to code",     GhcEnableTablesNextToCode);
+    mkRtsInfoPair("Tables next to code",     TablesNextToCode);
     mkRtsInfoPair("Flag -with-rtsopts",      /* See #15261 */
         rts_config.rts_opts != NULL ? rts_config.rts_opts : "");
     printf(" ]\n");
diff --git a/rts/ghc.mk b/rts/ghc.mk
index ae4dcd8..d913a9c 100644
--- a/rts/ghc.mk
+++ b/rts/ghc.mk
@@ -418,7 +418,7 @@ rts/RtsUtils_CC_OPTS += -DTargetOS=\"$(TargetOS_CPP)\"
 rts/RtsUtils_CC_OPTS += -DTargetVendor=\"$(TargetVendor_CPP)\"
 #
 rts/RtsUtils_CC_OPTS += -DGhcUnregisterised=\"$(GhcUnregisterised)\"
-rts/RtsUtils_CC_OPTS += -DGhcEnableTablesNextToCode=\"$(GhcEnableTablesNextToCode)\"
+rts/RtsUtils_CC_OPTS += -DTablesNextToCode=\"$(TablesNextToCode)\"
 #
 rts/xxhash_CC_OPTS += -O3 -ffast-math -ftree-vectorize