From ac741e26ab2797a0f0e7a3d9394d211b5ed39944 Mon Sep 17 00:00:00 2001
From: Stephen Heumann <stephenheumann@gmail.com>
Date: Tue, 29 Nov 2022 13:19:59 -0600
Subject: [PATCH] Allow nested auto structs/unions to be initialized with an
 expression of the same type.

When the expression is initially parsed, we do not necessarily know whether it is the initializer for the struct/union or for its first member. That needs to be determined based on the type. To support that, a new function is added to evaluate the expression separately from using it to initialize an object.
---
 Parser.pas | 50 ++++++++++++++++++++++++++++++++++++++++++++------
 cc.notes   |  2 ++
 2 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/Parser.pas b/Parser.pas
index c3514e4..eb3ec91 100644
--- a/Parser.pas
+++ b/Parser.pas
@@ -1858,6 +1858,7 @@ var
    disp: longint;                       {disp within overall object being initialized}
    done: boolean;                       {for loop termination}
    errorFound: boolean;                 {used to remove bad initializations}
+   haveExpression: boolean;             {has an expression been parsed but not used?}
    iPtr,jPtr,kPtr: initializerPtr;      {for reversing the list}
    ip: identList;                       {used to place an id in the list}
    isStatic: boolean;                   {static storage duration (or automatic)?}
@@ -1881,6 +1882,18 @@ var
    end; {InsertInitializerRecord}
 
 
+   procedure GetInitializerExpression;
+   
+   { get the expression for an initializer                       }
+   
+   begin {GetInitializerExpression}
+   if not isStatic then
+      Expression(autoInitializerExpression, [commach,rparench,rbracech])
+   else
+      Expression(initializerExpression, [commach,rparench,rbracech]);
+   end; {GetInitializerExpression}
+   
+
    procedure GetInitializerValue (tp: typePtr; bitsize,bitdisp: integer);
  
    { get the value of an initializer from a single expression    }
@@ -2011,10 +2024,12 @@ var
 
 
    begin {GetInitializerValue}
-   if not isStatic then
-      Expression(autoInitializerExpression, [commach,rparench,rbracech])
-   else
-      Expression(initializerExpression, [commach,rparench,rbracech]);
+   if not haveExpression then
+      GetInitializerExpression
+   else begin
+      NextToken;
+      haveExpression := false;
+      end; {else}
    iPtr := pointer(Malloc(sizeof(initializerRecord)));
    if bitsize <> 0 then
       size := (bitdisp + bitsize + 7) div 8
@@ -2590,6 +2605,26 @@ var
 
    {handle structures and unions}
    else if kind in [structType, unionType] then begin
+      if not braces then
+         if not nestedDesignator then
+            if not isStatic then
+               if (token.kind in startExpression-[stringconst]) then begin
+                  if not haveExpression then begin
+                     GetInitializerExpression;
+                     haveExpression := true;
+                     PutBackToken(token, false, true);
+                     token.kind := ident;  {dummy expression-starting token}
+                     token.class := identifier;
+                     token.name := @'__';
+                     token.symbolPtr := nil;                  
+                     while expressionType^.kind = definedType do
+                        expressionType := expressionType^.dType;
+                     end; {if}
+                  if CompTypes(tp, expressionType) then begin
+                     GetInitializerValue(tp, 0, 0);
+                     goto 1;
+                     end; {if}
+                  end; {if}
       if braces or (not main) then begin
          ip := tp^.fieldList;
          maxDisp := disp;
@@ -2695,8 +2730,10 @@ var
             end; {if}
          suppressMacroExpansions := lSuppressMacroExpansions;
          end {if}
-      else                              {struct/union assignment initializer}
-         GetInitializerValue(tp, bitsize, bitdisp);
+      else begin                        {struct/union assignment initializer}
+         Error(47);
+         errorFound := true;
+         end; {else}
       end {else if}
 
    {handle single-valued types}
@@ -2727,6 +2764,7 @@ var
 begin {Initializer}
 disp := 0;                              {start at beginning of the object}
 errorFound := false;                    {no errors found so far}
+haveExpression := false;                {no expression parsed yet}
                                         {static or automatic initialization?}
 isStatic := variable^.storage in [external,global,private];
 luseGlobalPool := useGlobalPool;        {use global memory for global vars}
diff --git a/cc.notes b/cc.notes
index 4ec4255..44fc397 100644
--- a/cc.notes
+++ b/cc.notes
@@ -1976,6 +1976,8 @@ int foo(int[42]);
 
 220. In certain cases where a header starts or ends in the middle of a declaration, it would not be represented correctly in the .sym file.  This could cause errors or misbehavior on subsequent compiles.
 
+221. Structures with unnamed bit-fields were sometimes initialized incorrectly.
+
 -- Bugs from C 2.1.0 that have been fixed -----------------------------------
 
 1.  In some situations, fread() reread the first 1K or so of the file.