diff --git a/AST.hs b/AST.hs
index 894ced4..2a9aeb0 100644
--- a/AST.hs
+++ b/AST.hs
@@ -54,6 +54,9 @@ instance Show Name where
 instance Eq Name where
   (==) a b = nameName a == nameName b
 
+instance Ord Name where
+  compare a b = compare (nameName a) (nameName b)
+
 -- | The definition of a name.
 data NameDef = NameDef {
     -- | Metadata.
diff --git a/CompState.hs b/CompState.hs
index e1081ec..02fcac9 100644
--- a/CompState.hs
+++ b/CompState.hs
@@ -22,6 +22,7 @@ module CompState where
 import Data.Generics
 import Data.Map (Map)
 import qualified Data.Map as Map
+import Data.Set (Set)
 import qualified Data.Set as Set
 import Control.Monad.State
 
@@ -52,7 +53,7 @@ data CompState = CompState {
 
     -- Set by preprocessor
     csCurrentFile :: String,
-    csUsedFiles :: Set.Set String,
+    csUsedFiles :: Set String,
 
     -- Set by Parse
     csLocalNames :: [(String, A.Name)],
@@ -69,9 +70,7 @@ data CompState = CompState {
     csFunctionReturns :: Map String [A.Type],
     csPulledItems :: [[A.Structured -> A.Structured]],
     csAdditionalArgs :: Map String [A.Actual],
-
-    -- Set by code generators
-    csGeneratedDefs :: [String]
+    csParProcs :: Set A.Name
   }
   deriving (Show, Data, Typeable)
 
@@ -102,8 +101,7 @@ emptyState = CompState {
     csFunctionReturns = Map.empty,
     csPulledItems = [],
     csAdditionalArgs = Map.empty,
-
-    csGeneratedDefs = []
+    csParProcs = Set.empty
   }
 
 -- | Class of monads which keep a CompState.
@@ -168,19 +166,6 @@ applyPulled ast
                          return $ foldl (\p f -> f p) ast l
 --}}}
 
---{{{  generated definitions
--- | Add a generated definition to the collection.
-addGeneratedDef :: CSM m => String -> m ()
-addGeneratedDef s = modify (\ps -> ps { csGeneratedDefs = s : csGeneratedDefs ps })
-
--- | Get and clear the collection of generated definitions.
-getGeneratedDefs :: CSM m => m [String]
-getGeneratedDefs
-    =  do ps <- get
-          put $ ps { csGeneratedDefs = [] }
-          return $ csGeneratedDefs ps
---}}}
-
 --{{{  type contexts
 -- | Enter a type context.
 pushTypeContext :: CSM m => Maybe A.Type -> m ()
diff --git a/GenerateC.hs b/GenerateC.hs
index ee7b568..1fdbd09 100644
--- a/GenerateC.hs
+++ b/GenerateC.hs
@@ -20,8 +20,10 @@ with this program.  If not, see <http://www.gnu.org/licenses/>.
 module GenerateC where
 
 import Data.Char
+import Data.Generics
 import Data.List
 import Data.Maybe
+import qualified Data.Set as Set
 import Control.Monad.Writer
 import Control.Monad.Error
 import Control.Monad.State
@@ -39,6 +41,29 @@ import TLP
 import Types
 import Utils
 
+--{{{  passes related to C generation
+genCPasses :: [(String, Pass)]
+genCPasses =
+  [ ("Identify parallel processes", identifyParProcs)
+  ]
+
+-- | Identify processes that we'll need to compute the stack size of.
+identifyParProcs :: Pass
+identifyParProcs = everywhereM (mkM doProcess)
+  where
+    doProcess :: A.Process -> PassM A.Process
+    doProcess p@(A.Par _ _ s) = findProcs s >> return p
+    doProcess p = return p
+
+    findProcs :: A.Structured -> PassM ()
+    findProcs (A.Rep _ _ s) = findProcs s
+    findProcs (A.Spec _ _ s) = findProcs s
+    findProcs (A.ProcThen _ _ s) = findProcs s
+    findProcs (A.Several _ ss) = sequence_ $ map findProcs ss
+    findProcs (A.OnlyP _ (A.ProcCall _ n _))
+        = modify (\cs -> cs { csParProcs = Set.insert n (csParProcs cs) })
+--}}}
+
 --{{{  monad definition
 type CGen = WriterT [String] PassM
 
@@ -216,15 +241,13 @@ cgenOps = GenOps {
 --}}}
 
 --{{{  top-level
-generate :: GenOps -> String -> A.Process -> PassM String
-generate ops headerFileName ast
-    =  do (a, w) <- runWriterT (call genTopLevel ops ast)
-          gds <- getGeneratedDefs
-          let out = ["#include ",headerFileName,"\n"] ++ gds ++ w
+generate :: GenOps -> A.Process -> PassM String
+generate ops ast
+    =  do (a, out) <- runWriterT (call genTopLevel ops ast)
           return $ concat out
 
 generateC :: A.Process -> PassM String
-generateC = generate cgenOps "<tock_support.h>"
+generateC = generate cgenOps
 
 cgenTLPChannel :: GenOps -> TLPChannel -> CGen ()
 cgenTLPChannel _ TLPIn = tell ["in"]
@@ -233,7 +256,11 @@ cgenTLPChannel _ TLPError = tell ["err"]
 
 cgenTopLevel :: GenOps -> A.Process -> CGen ()
 cgenTopLevel ops p
-    =  do call genProcess ops p
+    =  do tell ["#include <tock_support.h>\n"]
+          cs <- get
+          tell ["extern int " ++ nameString n ++ "_stack_size;\n"
+                | n <- Set.toList $ csParProcs cs]
+          call genProcess ops p
           (name, chans) <- tlpInterface
           tell ["void tock_main (Process *me, Channel *in, Channel *out, Channel *err) {\n"]
           genName name
@@ -1638,7 +1665,6 @@ cgenPar ops pm s
         =  do tell ["ProcAlloc ("]
               genName n
               let stackSize = nameString n ++ "_stack_size"
-              addGeneratedDef $ "extern int " ++ stackSize ++ ";\n"
               tell [", ", stackSize, ", ", show $ numCArgs as]
               call genActuals ops as
               tell [")"]
diff --git a/GenerateCPPCSP.hs b/GenerateCPPCSP.hs
index 8e6eb14..60d6066 100644
--- a/GenerateCPPCSP.hs
+++ b/GenerateCPPCSP.hs
@@ -131,11 +131,12 @@ In occam-pi I could possibly use the channel-ends properly, but in occam 2.1 I h
 
 --{{{  top-level
 generateCPPCSP :: A.Process -> PassM String
-generateCPPCSP = generate cppgenOps "<tock_support_cppcsp.h>"
+generateCPPCSP = generate cppgenOps
 
 cppgenTopLevel :: GenOps -> A.Process -> CGen ()
 cppgenTopLevel ops p
-    =  do call genProcess ops p
+    =  do tell ["#include <tock_support_cppcsp.h>\n"]
+          call genProcess ops p
           (name, chans) <- tlpInterface
           tell ["int main (int argc, char** argv) { csp::Start_CPPCSP();"]
           tell ["csp::One2OneChannel<uint8_t> in,out,err;"] --TODO add streamreader
diff --git a/Main.hs b/Main.hs
index 270f223..737e2ef 100644
--- a/Main.hs
+++ b/Main.hs
@@ -163,6 +163,9 @@ compile fn
                                 , if csFrontend optsPS == FrontendRain
                                     then rainPasses
                                     else []
+                                , if csBackend optsPS == BackendC
+                                    then genCPasses
+                                    else []
                                 ]
                  ast2 <- runPasses passes ast1