[project @ 1998-08-14 11:45:04 by sof]

New module gathering together info on external calling convs

ghc/compiler/absCSyn/CallConv.lhs

+%
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+%
+\section[Calling conventions]{External calling conventions}
+
+\begin{code}
+module CallConv
+       (
+	 CallConv
+       , pprCallConv
+
+       , stdCallConv
+       , cCallConv
+       , callConvAttribute
+       , decorateExtName
+       ) where
+
+#include "HsVersions.h"
+
+import Outputable
+import PrimRep     ( PrimRep, getPrimRepSizeInBytes )
+\end{code}
+
+\begin{code}
+type CallConv = Int
+
+pprCallConv :: CallConv -> SDoc
+pprCallConv 0 = ptext SLIT("_stdcall")
+pprCallConv _ = ptext SLIT("_ccall")
+
+stdCallConv :: CallConv
+stdCallConv = 0
+
+cCallConv  :: CallConv
+cCallConv = 1
+\end{code}
+
+Generate the gcc attribute corresponding to the given
+calling convention (used by PprAbsC):
+
+ToDo: The stdcall calling convention is x86 (win32) specific,
+so perhaps we should emit a warning if it's being used on other
+platforms.
+
+\begin{code}
+callConvAttribute :: CallConv -> String
+callConvAttribute cc
+ | cc == stdCallConv   = "__attribute__((stdcall))"
+ | cc == cCallConv     = ""
+ | otherwise	       = panic ("callConvAttribute: cannot handle" ++ showSDoc (pprCallConv cc))
+
+\end{code}
+
+For stdcall and Win32, the linker expects to see names of the form 
+ 
+   "f@n"
+
+where n is the size (in 8-bit bytes) of the parameter area
+that is pushed onto the stack before invocation. We take
+care of mangling the function name here. 
+
+This name mangler is only used by the x86 native code generator.
+
+\begin{code}
+decorateExtName :: CallConv -> FAST_STRING -> [PrimRep] -> FAST_STRING
+decorateExtName cc fs ps
+{- ifdef COMPILING_WIN32 -}
+ | cc /= stdCallConv = fs
+ | otherwise	     = fs _APPEND_ (_PK_ ('@':show (size::Int)))
+{- else
+ = fs
+-}
+ where
+  size = sum (map (adjustParamSize.getPrimRepSizeInBytes) ps)
+
+  adjustParamSize sz =  paramBoundary * ((sz + paramBoundary - 1) `div` paramBoundary)
+
+  paramBoundary = 4
+
+\end{code}