Link with libm dynamically (#19877)

The compiler should be independent of the target.

4 files changed, 16 insertions, 10 deletions

diff --git a/compiler/GHC/Linker/Dynamic.hs b/compiler/GHC/Linker/Dynamic.hs
index e8c31a1f20..3eca65c6cc 100644
--- a/compiler/GHC/Linker/Dynamic.hs
+++ b/compiler/GHC/Linker/Dynamic.hs
@@ -197,7 +197,8 @@ linkDynLib logger tmpfs dflags0 unit_env o_files dep_packages
             -------------------------------------------------------------------
 
             let output_fn = case o_file of { Just s -> s; Nothing -> "a.out"; }
-                unregisterised = platformUnregisterised (targetPlatform dflags)
+                platform  = targetPlatform dflags
+                unregisterised = platformUnregisterised platform
             let bsymbolicFlag = -- we need symbolic linking to resolve
                                 -- non-PIC intra-package-relocations for
                                 -- performance (where symbolic linking works)
@@ -206,7 +207,7 @@ linkDynLib logger tmpfs dflags0 unit_env o_files dep_packages
 
             runLink logger tmpfs dflags (
                     map Option verbFlags
-                 ++ libmLinkOpts
+                 ++ libmLinkOpts platform
                  ++ [ Option "-o"
                     , FileOption "" output_fn
                     ]
@@ -224,13 +225,10 @@ linkDynLib logger tmpfs dflags0 unit_env o_files dep_packages
 
 -- | Some platforms require that we explicitly link against @libm@ if any
 -- math-y things are used (which we assume to include all programs). See #14022.
-libmLinkOpts :: [Option]
-libmLinkOpts =
-#if defined(HAVE_LIBM)
-  [Option "-lm"]
-#else
-  []
-#endif
+libmLinkOpts :: Platform -> [Option]
+libmLinkOpts platform
+  | platformHasLibm platform = [Option "-lm"]
+  | otherwise                = []
 
 {-
 Note [-Bsymbolic assumptions by GHC]
diff --git a/compiler/GHC/Linker/Static.hs b/compiler/GHC/Linker/Static.hs
index c4549d5274..ed67daa347 100644
--- a/compiler/GHC/Linker/Static.hs
+++ b/compiler/GHC/Linker/Static.hs
@@ -197,7 +197,7 @@ linkBinary' staticLink logger tmpfs dflags unit_env o_files dep_units = do
                       ++ [ GHC.SysTools.Option "-o"
                          , GHC.SysTools.FileOption "" output_fn
                          ]
-                      ++ libmLinkOpts
+                      ++ libmLinkOpts platform
                       ++ map GHC.SysTools.Option (
                          []
 
diff --git a/compiler/GHC/Platform.hs b/compiler/GHC/Platform.hs
index b3f5bf830c..9bebcc5990 100644
--- a/compiler/GHC/Platform.hs
+++ b/compiler/GHC/Platform.hs
@@ -74,6 +74,11 @@ data Platform = Platform
       -- ^ 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 rts/include/rts/storage/InfoTables.h.
+   , platformHasLibm                  :: !Bool
+      -- ^ Some platforms require that we explicitly link against @libm@ if any
+      -- math-y things are used (which we assume to include all programs). See
+      -- #14022.
+
    , platform_constants               :: !(Maybe PlatformConstants)
       -- ^ Constants such as structure offsets, type sizes, etc.
    }
@@ -93,6 +98,7 @@ genericPlatform = Platform
    , platformHasGnuNonexecStack      = False
    , platformHasIdentDirective       = False
    , platformHasSubsectionsViaSymbols= False
+   , platformHasLibm                 = False
    , platformIsCrossCompiling        = False
    , platformLeadingUnderscore       = False
    , platformTablesNextToCode        = True
diff --git a/compiler/GHC/Settings/IO.hs b/compiler/GHC/Settings/IO.hs
index 3c4e012675..49dd910d43 100644
--- a/compiler/GHC/Settings/IO.hs
+++ b/compiler/GHC/Settings/IO.hs
@@ -235,6 +235,7 @@ getTargetPlatform settingsFile settings = do
   targetHasGnuNonexecStack <- getBooleanSetting "target has GNU nonexec stack"
   targetHasIdentDirective <- getBooleanSetting "target has .ident directive"
   targetHasSubsectionsViaSymbols <- getBooleanSetting "target has subsections via symbols"
+  targetHasLibm <- getBooleanSetting "target has libm"
   crossCompiling <- getBooleanSetting "cross compiling"
   tablesNextToCode <- getBooleanSetting "Tables next to code"
 
@@ -249,5 +250,6 @@ getTargetPlatform settingsFile settings = do
     , platformIsCrossCompiling = crossCompiling
     , platformLeadingUnderscore = targetLeadingUnderscore
     , platformTablesNextToCode  = tablesNextToCode
+    , platformHasLibm = targetHasLibm
     , platform_constants = Nothing -- will be filled later when loading (or building) the RTS unit
     }