Revert "Revert "fix Issue 23875 23880 (#15172)" (#15196)"

This reverts commit 7da9317.

compiler/src/dmd/cparse.d

@@ -324,6 +324,8 @@ final class CParser(AST) : Parser!AST
         // atomic-type-specifier or type_qualifier
         case TOK._Atomic:
 
+        case TOK.__attribute__:
+
         Ldeclaration:
         {
             cparseDeclaration(LVL.local);
@@ -2710,20 +2712,34 @@ final class CParser(AST) : Parser!AST
      *
      * Params:
      *  declarator   = declarator kind
-     *  t            = base type to start with
+     *  tbase        = base type to start with
      *  pident       = set to Identifier if there is one, null if not
      *  specifier    = specifiers in and out
      * Returns:
      *  type declared. If a TypeFunction is returned, this.symbols is the
      *  symbol table for the parameter-type-list, which will contain any
      *  declared struct, union or enum tags.
      */
-    private AST.Type cparseDeclarator(DTR declarator, AST.Type t,
+    private AST.Type cparseDeclarator(DTR declarator, AST.Type tbase,
         out Identifier pident, ref Specifier specifier)
     {
         //printf("cparseDeclarator(%d, %p)\n", declarator, t);
         AST.Types constTypes; // all the Types that will need `const` applied to them
 
+        /* Insert tx -> t into
+         *   ts -> ... -> t
+         * so that
+         *   ts -> ... -> tx -> t
+         */
+        static void insertTx(ref AST.Type ts, AST.Type tx, AST.Type t)
+        {
+            AST.Type* pt;
+            for (pt = &ts; *pt != t; pt = &(cast(AST.TypeNext)*pt).next)
+            {
+            }
+            *pt = tx;
+        }
+
         AST.Type parseDecl(AST.Type t)
         {
             AST.Type ts;
@@ -2789,20 +2805,6 @@ final class CParser(AST) : Parser!AST
             // parse DeclaratorSuffixes
             while (1)
             {
-                /* Insert tx -> t into
-                 *   ts -> ... -> t
-                 * so that
-                 *   ts -> ... -> tx -> t
-                 */
-                static void insertTx(ref AST.Type ts, AST.Type tx, AST.Type t)
-                {
-                    AST.Type* pt;
-                    for (pt = &ts; *pt != t; pt = &(cast(AST.TypeNext)*pt).next)
-                    {
-                    }
-                    *pt = tx;
-                }
-
                 switch (token.value)
                 {
                     case TOK.leftBracket:
@@ -2915,7 +2917,17 @@ final class CParser(AST) : Parser!AST
             return ts;
         }
 
-        t = parseDecl(t);
+        auto t = parseDecl(tbase);
+
+        if (specifier.vector_size)
+        {
+            auto length = new AST.IntegerExp(token.loc, specifier.vector_size / tbase.size(), AST.Type.tuns32);
+            auto tsa = new AST.TypeSArray(tbase, length);
+            AST.Type tv = new AST.TypeVector(tsa);
+            specifier.vector_size = 0;          // used it up
+
+            insertTx(t, tv, tbase);     // replace tbase with tv
+        }
 
         /* Because const is transitive, cannot assemble types from
          * fragments. Instead, types to be annotated with const are put
@@ -3553,7 +3565,19 @@ final class CParser(AST) : Parser!AST
             {
                 nextToken();
                 check(TOK.leftParenthesis);
-                cparseConstantExp();  // TODO implement
+                if (token.value == TOK.int32Literal)
+                {
+                    const n = token.unsvalue;
+                    if (n < 1 || n & (n - 1) || ushort.max < n)
+                        error("__attribute__((vector_size(%lld))) must be an integer positive power of 2 and be <= 32,768", cast(ulong)n);
+                    specifier.vector_size = cast(uint) n;
+                    nextToken();
+                }
+                else
+                {
+                    error("value for vector_size expected, not `%s`", token.toChars());
+                    nextToken();
+                }
                 check(TOK.rightParenthesis);
             }
             else
@@ -4694,6 +4718,7 @@ final class CParser(AST) : Parser!AST
                 // atomic-type-specifier
                 case TOK._Atomic:
                 case TOK.typeof_:
+                case TOK.__attribute__:
                     t = peek(t);
                     if (t.value != TOK.leftParenthesis ||
                         !skipParens(t, &t))
@@ -4959,6 +4984,7 @@ final class CParser(AST) : Parser!AST
         bool dllexport; /// dllexport attribute
         bool _deprecated;       /// deprecated attribute
         AST.Expression depMsg;  /// deprecated message
+        uint vector_size;       /// positive power of 2 multipe of base type size
 
         SCW scw;        /// storage-class specifiers
         MOD mod;        /// type qualifiers

compiler/src/dmd/initsem.d

@@ -587,6 +587,9 @@ extern(C++) Initializer initializerSemantic(Initializer init, Scope* sc, ref Typ
          */
         t = t.toBasetype();
 
+        if (auto tv = t.isTypeVector())
+            t = tv.basetype;
+
         /* If `{ expression }` return the expression initializer
          */
         ExpInitializer isBraceExpression()

compiler/test/compilable/test23875.c

@@ -0,0 +1,28 @@
+/* DISABLED: win32 linux32
+ */
+
+// https://issues.dlang.org/show_bug.cgi?id=23875
+// https://issues.dlang.org/show_bug.cgi?id=23880
+
+int __attribute__((vector_size(16))) neptune()
+{
+    int __attribute__((vector_size (16))) v = { 4,1,2,3 };
+    return v;
+}
+
+__attribute__((__vector_size__(16))) int pluto(int i)
+{
+    int __attribute__((__vector_size__ (16))) * p1;
+    int * __attribute__((__vector_size__ (16))) p2;
+
+    int __attribute__((__vector_size__ (16))) v1;
+    __attribute__((__vector_size__ (16))) int v2;
+
+    v1 = (__attribute__((__vector_size__ (16))) int) {4,1,2,3};
+
+    p1 = p2;
+    *p1 = v1;
+    v1 = (__attribute__((__vector_size__ (16))) int) v2;
+
+    return i ? v1 : v2;
+}

compiler/test/fail_compilation/test23875.c

@@ -0,0 +1,13 @@
+/* DISABLED: win32 linux32
+TEST_OUTPUT:
+---
+fail_compilation/test23875.c(12): Error: __attribute__((vector_size(10))) must be an integer positive power of 2 and be <= 32,768
+fail_compilation/test23875.c(13): Error: value for vector_size expected, not `x`
+---
+*/
+
+// https://issues.dlang.org/show_bug.cgi?id=23875
+// https://issues.dlang.org/show_bug.cgi?id=23880
+
+int __attribute__((vector_size(10))) neptune();
+int __attribute__((vector_size(x))) saturn();

druntime/src/importc.h

@@ -32,6 +32,7 @@
 #define __volatile__ volatile
 #define __attribute __attribute__
 #define __alignof _Alignof
+#define __vector_size__ vector_size
 
 /********************
  * Clang nullability extension used by macOS headers.