factored out some common bitfield code

Author: totalspectrum

frontends/c/cgram.y

@@ -619,7 +619,6 @@ DeclareCMemberVariables(Module *P, AST *astlist, int is_union)
     AST *ast;
     BitFieldState bitfield = { 0 };
     int is_private = -P->defaultPrivate;
-    AST *last_pos = 0;
 
     if (!astlist) return;
     if (astlist->kind != AST_STMTLIST) {
@@ -673,59 +672,12 @@ DeclareCMemberVariables(Module *P, AST *astlist, int is_union)
             }
             while (idlist) {
                 ident = idlist->left;
-                // not in a bitfield
-                bitfield.max_size = bitfield.offset = 0;
                 MaybeDeclareMemberVar(P, ident, typ, is_private, NORMAL_VAR, &bitfield);
                 idlist = idlist->right;
             }
         } else {
             ident = idlist;
-            if (typ->kind == AST_BITFIELD) {
-                AST *bfield_ast = typ->right;
-                AST *bfield_typ = typ->left;
-                AST *bfield_access;
-                AST *bfield_list = 0;
-                int tsize;
-                int bsize = EvalConstExpr(bfield_ast);
-                Symbol *sym = FindSymbol(&P->objsyms, GetIdentifierName(ident));
-
-                if (sym && sym->kind == SYM_ALIAS) {
-                    goto skip_decl;
-                }
-                tsize = TypeSize(bfield_typ) * 8;
-                if (bitfield.max_size == 0 || bitfield.max_size != tsize || bitfield.offset + bsize > bitfield.max_size) {
-                    // start a new bitfield
-                    bitfield.max_size = tsize;
-                    bitfield.offset = 0;
-                    bitfield.ident = AstTempIdentifier("^_bitfield_");
-                    last_pos = MaybeDeclareMemberVar(P, bitfield.ident, bfield_typ, is_private, HIDDEN_VAR, &bitfield);
-                }
-                if (bsize > bitfield.max_size) {
-                    ERROR(bfield_ast, "bitfield size %d is greater than type size %d",
-                          bsize, bitfield.max_size);
-                    bsize = bitfield.max_size;
-                }
-                if (bsize < 0) {
-                    bsize = 1;
-                }
-                bfield_access = NewAST(AST_RANGE, AstInteger(bitfield.offset + bsize - 1), AstInteger(bitfield.offset));
-                if (!IsUnsignedType(bfield_typ)) {
-                    bfield_access->d.ival = 1;
-                }
-                bfield_access = NewAST(AST_RANGEREF, bitfield.ident, bfield_access);
-                bfield_access = NewAST(AST_CAST, bfield_typ, bfield_access);
-                DeclareMemberAlias(P, ident, bfield_access);
-                bfield_list = NewAST(AST_DECLARE_BITFIELD, bfield_access, ident);
-                bfield_list = NewAST(AST_LISTHOLDER, bfield_list, NULL);
-                P->pendingvarblock = ListInsertBefore(P->pendingvarblock, last_pos, bfield_list);
-                bitfield.offset += bsize;
-            skip_decl:
-                ;
-            } else {
-                // not in a bitfield
-                bitfield.max_size = bitfield.offset = 0;
-                MaybeDeclareMemberVar(P, ident, typ, is_private, NORMAL_VAR, &bitfield);
-            }
+            MaybeDeclareMemberVar(P, ident, typ, is_private, NORMAL_VAR, &bitfield);
         }
     }
 

frontends/common.c

@@ -2276,8 +2276,8 @@ AlreadyDeclared(AST *pendinglist, AST *newIdentifier)
     return NULL;
 }
 
-AST *
-MaybeDeclareMemberVar(Module *P, AST *identifier, AST *typ, int is_private, unsigned flags, BitFieldState *bitfield)
+static AST *
+doMaybeDeclareMemberVar(Module *P, AST *identifier, AST *typ, int is_private, unsigned flags, BitFieldState *bitfield)
 {
     AST *ret = 0;
     AST *sub;
@@ -2319,6 +2319,67 @@ MaybeDeclareMemberVar(Module *P, AST *identifier, AST *typ, int is_private, unsi
     return ret;
 }
 
+AST *
+MaybeDeclareMemberVar(Module *P, AST *ident, AST *typ, int is_private, unsigned flags, BitFieldState *bitfield)
+{
+    AST *ret = NULL;
+    if (typ && typ->kind == AST_BITFIELD) {
+        AST *bfield_ast = typ->right;
+        AST *bfield_typ = typ->left;
+        AST *bfield_access;
+        AST *bfield_list = 0;
+        int tsize;
+        int bsize = EvalConstExpr(bfield_ast);
+        Symbol *sym = FindSymbol(&P->objsyms, GetIdentifierName(ident));
+
+        if (!bitfield) {
+            ERROR(ident, "Unexpected bitfield declaration");
+            return ret;
+        }
+        if (sym && sym->kind == SYM_ALIAS) {
+            goto skip_decl;
+        }
+        tsize = TypeSize(bfield_typ) * 8;
+        if (bitfield->max_size == 0 || bitfield->max_size != tsize || bitfield->offset + bsize > bitfield->max_size) {
+            // start a new bitfield
+            bitfield->max_size = tsize;
+            bitfield->offset = 0;
+            bitfield->ident = AstTempIdentifier("^_bitfield_");
+            ret = doMaybeDeclareMemberVar(P, bitfield->ident, bfield_typ, is_private, HIDDEN_VAR, NULL);
+            bitfield->last_bfield_pos = ret;
+        }
+        if (bsize > bitfield->max_size) {
+            ERROR(bfield_ast, "bitfield size %d is greater than type size %d",
+                  bsize, bitfield->max_size);
+            bsize = bitfield->max_size;
+        }
+        if (bsize < 0) {
+            bsize = 1;
+        }
+        bfield_access = NewAST(AST_RANGE, AstInteger(bitfield->offset + bsize - 1), AstInteger(bitfield->offset));
+        if (!IsUnsignedType(bfield_typ)) {
+            bfield_access->d.ival = 1;
+        }
+        bfield_access = NewAST(AST_RANGEREF, bitfield->ident, bfield_access);
+        bfield_access = NewAST(AST_CAST, bfield_typ, bfield_access);
+        DeclareMemberAlias(P, ident, bfield_access);
+        bfield_list = NewAST(AST_DECLARE_BITFIELD, bfield_access, ident);
+        bfield_list = NewAST(AST_LISTHOLDER, bfield_list, NULL);
+        P->pendingvarblock = ListInsertBefore(P->pendingvarblock,
+                                              bitfield->last_bfield_pos, bfield_list);
+        bitfield->offset += bsize;
+    skip_decl:
+        ;
+    } else {
+        // not in a bitfield
+        if (bitfield) {
+            bitfield->max_size = bitfield->offset = 0;
+        }
+        ret = doMaybeDeclareMemberVar(P, ident, typ, is_private, flags, bitfield);
+    }
+    return ret;
+}
+
 void
 DeclareInterfaceFunctionPointers(Module *P)
 {

frontends/common.h

@@ -998,6 +998,7 @@ typedef struct BitFieldState {
     AST *ident;    /* identifier for bitfield container (usually anonymous) */
     int max_size;  /* maximum number of bits to hold */
     int offset;    /* offset for next bitfield */
+    AST *last_bfield_pos; /* last declared bitfield variable */
 } BitFieldState;