[commit: ghc] master: UNREG: fix "_bytes" string literal forward declaration (34a0205)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/34a0205587c8c6017a26ddf7023e91789da2e81b/ghc

>---------------------------------------------------------------

commit 34a0205587c8c6017a26ddf7023e91789da2e81b
Author: Sergei Trofimovich <siarheit at google.com>
Date:   Sun Jan 29 18:39:48 2017 +0000

    UNREG: fix "_bytes" string literal forward declaration
    
    Typical UNREG build failure looks like that:
    
      ghc-unreg/includes/Stg.h:226:46: error:
         note: in definition of macro 'EI_'
         #define EI_(X)          extern StgWordArray (X) GNU_ATTRIBUTE(aligned (8))
                                                      ^
          |
      226 | #define EI_(X)          extern StgWordArray (X) GNU_ATTRIBUTE(aligned (8))
          |                                              ^
    
      /tmp/ghc10489_0/ghc_3.hc:1754:6: error:
         note: previous definition of 'ghczmprim_GHCziTypes_zdtcTyCon2_bytes' was here
         char ghczmprim_GHCziTypes_zdtcTyCon2_bytes[] = "TyCon";
              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           |
      1754 | char ghczmprim_GHCziTypes_zdtcTyCon2_bytes[] = "TyCon";
           |      ^
    
    As we see here "_bytes" string literals are defined as 'char []'
    array, not 'StgWord []'.
    
    The change special-cases "_bytes" string literals to have
    correct declaration type.
    
    Signed-off-by: Sergei Trofimovich <siarheit at google.com>


>---------------------------------------------------------------

34a0205587c8c6017a26ddf7023e91789da2e81b
 compiler/cmm/CLabel.hs | 6 ++++++
 compiler/cmm/PprC.hs   | 3 ++-
 includes/Stg.h         | 1 +
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/compiler/cmm/CLabel.hs b/compiler/cmm/CLabel.hs
index ee87ef1..2f38203 100644
--- a/compiler/cmm/CLabel.hs
+++ b/compiler/cmm/CLabel.hs
@@ -89,6 +89,7 @@ module CLabel (
         addLabelSize,
 
         foreignLabelStdcallInfo,
+        isBytesLabel,
         isForeignLabel,
         mkCCLabel, mkCCSLabel,
 
@@ -573,6 +574,11 @@ addLabelSize (ForeignLabel str _ src  fod) sz
 addLabelSize label _
     = label
 
+-- | Whether label is a top-level string literal
+isBytesLabel :: CLabel -> Bool
+isBytesLabel (IdLabel _ _ Bytes) = True
+isBytesLabel _lbl = False
+
 -- | Whether label is a non-haskell label (defined in C code)
 isForeignLabel :: CLabel -> Bool
 isForeignLabel (ForeignLabel _ _ _ _) = True
diff --git a/compiler/cmm/PprC.hs b/compiler/cmm/PprC.hs
index 6380451..811d908 100644
--- a/compiler/cmm/PprC.hs
+++ b/compiler/cmm/PprC.hs
@@ -1007,7 +1007,8 @@ pprExternDecl _in_srt lbl
         hcat [ visibility, label_type lbl,
                lparen, ppr lbl, text ");" ]
  where
-  label_type lbl | isForeignLabel lbl && isCFunctionLabel lbl = text "FF_"
+  label_type lbl | isBytesLabel lbl     = text "B_"
+                 | isForeignLabel lbl && isCFunctionLabel lbl = text "FF_"
                  | isCFunctionLabel lbl = text "F_"
                  | otherwise            = text "I_"
 
diff --git a/includes/Stg.h b/includes/Stg.h
index f1949b1..e3de331 100644
--- a/includes/Stg.h
+++ b/includes/Stg.h
@@ -223,6 +223,7 @@ typedef StgInt    I_;
 typedef StgWord StgWordArray[];
 typedef StgFunPtr       F_;
 
+#define EB_(X)    extern char X[]
 #define EI_(X)          extern StgWordArray (X) GNU_ATTRIBUTE(aligned (8))
 #define II_(X)          static StgWordArray (X) GNU_ATTRIBUTE(aligned (8))
 #define IF_(f)    static StgFunPtr GNUC3_ATTRIBUTE(used) f(void)