diff --git a/CHANGELOG b/CHANGELOG --- a/CHANGELOG +++ b/CHANGELOG @@ -1,3 +1,11 @@ +2022-07-07 + * Version bump (3.10). (#356) + * Remove unnecessary dependencies from Cabal package. (#323) + * Remove duplicated compiler option. (#328) + * Pass structs by reference, not value, in handlers. (#305) + * Relax version bounds of dependencies. (#335) + * Update repo info in cabal file. (#333) + 2022-05-06 * Version bump (3.9). (#320) * Compliance with style guide (partial). (#316) diff --git a/copilot-c99.cabal b/copilot-c99.cabal --- a/copilot-c99.cabal +++ b/copilot-c99.cabal @@ -1,6 +1,6 @@ cabal-version : >= 1.10 name : copilot-c99 -version : 3.9 +version : 3.10 synopsis : A compiler for Copilot targeting C99. description : This package is a back-end from Copilot to C. @@ -31,8 +31,8 @@ source-repository head type: git - location: git://github.com/Copilot-Language/copilot.git - subdir: lib/copilot-c99 + location: https://github.com/Copilot-Language/copilot.git + subdir: copilot-c99 library default-language : Haskell2010 @@ -42,17 +42,15 @@ -- https://github.com/Copilot-Language/copilot/issues/237 -- It should be removed in a future version, when this library hides -- internal modules. - ghc-options : -Wall -fwarn-tabs -Wno-deprecations + ghc-options : -Wall -Wno-deprecations build-depends : base >= 4.9 && < 5 - , containers >= 0.4 && < 0.7 , directory >= 1.3 && < 1.4 , filepath >= 1.4 && < 1.5 - , mtl >= 2.2 && < 2.3 + , mtl >= 2.2 && < 2.4 , pretty >= 1.1 && < 1.2 - , copilot-core >= 3.9 && < 3.10 + , copilot-core >= 3.10 && < 3.11 , language-c99 >= 0.1.1 && < 0.2 - , language-c99-util >= 0.1.1 && < 0.2 , language-c99-simple >= 0.1.1 && < 0.2 exposed-modules : Copilot.Compile.C99 diff --git a/src/Copilot/Compile/C99/CodeGen.hs b/src/Copilot/Compile/C99/CodeGen.hs --- a/src/Copilot/Compile/C99/CodeGen.hs +++ b/src/Copilot/Compile/C99/CodeGen.hs @@ -79,12 +79,16 @@ void = C.TypeSpec C.Void stmts = map mkexcopy exts - ++ map mktriggercheck triggers + ++ triggerStmts ++ tmpassigns ++ bufferupdates ++ indexupdates - (declns, tmpassigns, bufferupdates, indexupdates) = + declns = streamDeclns + ++ concat triggerDeclns + (streamDeclns, tmpassigns, bufferupdates, indexupdates) = unzip4 $ map mkupdateglobals streams + (triggerDeclns, triggerStmts) = + unzip $ map mktriggercheck triggers -- Write code to update global stream buffers and index. mkupdateglobals :: Stream -> (C.Decln, C.Stmt, C.Stmt, C.Stmt) @@ -129,13 +133,85 @@ _ -> C.Ident cpyname C..= C.Ident name - -- Make if-statement to check the guard, call the trigger if necessary. - mktriggercheck :: Trigger -> C.Stmt - mktriggercheck (Trigger name guard args) = C.If guard' firetrigger + -- Make if-statement to check the guard, call the handler if necessary. + -- This returns two things: + -- + -- * A list of Declns for temporary variables, one for each argument that + -- the handler function accepts. For example, if a handler function takes + -- three arguments, the list of Declns might look something like this: + -- + -- @ + -- int8_t handler_arg_temp0; + -- int16_t handler_arg_temp1; + -- struct s handler_arg_temp2; + -- @ + -- + -- * A Stmt representing the if-statement. Continuing the example above, + -- the if-statement would look something like this: + -- + -- @ + -- if (handler_guard()) { + -- handler_arg_temp0 = handler_arg0(); + -- handler_arg_temp1 = handler_arg1(); + -- handler_arg_temp2 = handler_arg2(); + -- handler(handler_arg_temp0, handler_arg_temp1, &handler_arg_temp2); + -- } + -- @ + -- + -- We create temporary variables because: + -- + -- 1. We want to pass structs by reference intead of by value. To this end, + -- we use C's & operator to obtain a reference to a temporary variable + -- of a struct type and pass that to the handler function. + -- + -- 2. Assigning a struct to a temporary variable defensively ensures that + -- any modifications that the handler called makes to the struct argument + -- will not affect the internals of the monitoring code. + mktriggercheck :: Trigger -> ([C.Decln], C.Stmt) + mktriggercheck (Trigger name guard args) = + (aTmpDeclns, ifStmt) where - guard' = C.Funcall (C.Ident $ guardname name) [] - firetrigger = [C.Expr $ C.Funcall (C.Ident name) args'] + aTmpDeclns = zipWith (\tmpVar arg -> + C.VarDecln Nothing (tempType arg) tmpVar Nothing) + aTempNames + args where + tempType (UExpr { uExprType = ty }) = + case ty of + -- If a temporary variable is being used to store an array, + -- declare the type of the temporary variable as a pointer, not + -- an array. The problem with declaring it as an array is that + -- the `arg` function will return a pointer, not an array, and + -- C doesn't make it easy to cast directly from an array to a + -- pointer. + Array ty' -> C.Ptr $ transtype ty' + _ -> transtype ty + + aTempNames = take (length args) (argTempNames name) + + ifStmt = C.If guard' firetrigger + + guard' = C.Funcall (C.Ident $ guardname name) [] + + -- The body of the if-statement. This consists of statements that assign + -- the values of the temporary variables, following by a final statement + -- that passes the temporary variables to the handler function. + firetrigger = map C.Expr argAssigns ++ + [C.Expr $ C.Funcall (C.Ident name) + (zipWith passArg aTempNames args)] + where + passArg aTempName (UExpr { uExprType = ty }) = + case ty of + -- Special case for Struct to pass reference to temporary + -- struct variable to handler. (See the comments for + -- mktriggercheck for details.) + Struct _ -> C.UnaryOp C.Ref $ C.Ident aTempName + _ -> C.Ident aTempName + + argAssigns = zipWith (\aTempName arg -> + C.AssignOp C.Assign (C.Ident aTempName) arg) + aTempNames + args' args' = take (length args) (map argcall (argnames name)) argcall name = C.Funcall (C.Ident name) [] diff --git a/src/Copilot/Compile/C99/Compile.hs b/src/Copilot/Compile/C99/Compile.hs --- a/src/Copilot/Compile/C99/Compile.hs +++ b/src/Copilot/Compile/C99/Compile.hs @@ -157,7 +157,15 @@ where cty = C.TypeSpec C.Void params = map mkparam $ zip (argnames name) args - mkparam (name, UExpr ty _) = C.Param (transtype ty) name + mkparam (name, UExpr ty _) = C.Param (mkParamTy ty) name + + -- Special case for Struct, to pass struct arguments by reference. + -- Arrays are also passed by reference, but using C's array type + -- does that automatically. + mkParamTy ty = + case ty of + Struct _ -> C.Ptr (transtype ty) + _ -> transtype ty -- Declaration for the step function. stepdecln :: C.Decln diff --git a/src/Copilot/Compile/C99/Util.hs b/src/Copilot/Compile/C99/Util.hs --- a/src/Copilot/Compile/C99/Util.hs +++ b/src/Copilot/Compile/C99/Util.hs @@ -55,9 +55,18 @@ argname :: String -> Int -> String argname name n = name ++ "_arg" ++ show n +-- | Turn a handler function name into a name for a temporary variable for a +-- handler argument. +argTempName :: String -> Int -> String +argTempName name n = name ++ "_arg_temp" ++ show n + -- | Enumerate all argument names based on trigger name. argnames :: String -> [String] argnames base = [aname | n <- [0..], let aname = argname base n] + +-- | Enumerate all temporary variable names based on handler function name. +argTempNames :: String -> [String] +argTempNames base = map (argTempName base) [0..] -- | Define a C expression that calls a function with arguments. funcall :: C.Ident -> [C.Expr] -> C.Expr