From 9a7dc23c5d5e68b034d4e16ceff2e9227b52d173 Mon Sep 17 00:00:00 2001
From: Stephen Heumann <stephenheumann@gmail.com>
Date: Sun, 30 Oct 2022 18:54:40 -0500
Subject: [PATCH] When a symbol is multiply declared, form the composite type.

Previously, it generally just used the later type (except for function types where only the earlier one included a prototype). One effect of this is that if a global array is first declared with a size and then redeclared without one, the size information is lost, causing the proper space not to be allocated.

See C17 section 6.2.7 p4.

Here is an example affected by the array issue (dump the object file to see the size allocated):

int foo[50];
int foo[];
---
 Symbol.pas | 12 ++++++++----
 cc.notes   |  2 ++
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/Symbol.pas b/Symbol.pas
index b5950f9..8535d55 100644
--- a/Symbol.pas
+++ b/Symbol.pas
@@ -2040,12 +2040,10 @@ if space <> fieldListSpace then begin   {are we defining a function?}
          if cs^.state = defined then
             if state = defined then
                Error(42);
+         if cs^.itype <> nil then
+            itype := MakeCompositeType(cs^.itype, itype);
          p := cs;
          needSymbol := false;
-         if not itype^.prototyped then begin
-            itype^.prototyped := cs^.itype^.prototyped;
-            itype^.parameterList := cs^.itype^.parameterList;
-            end; {if}
          end; {if}
       end {if}
    else if (itype <> nil) and (itype^.kind in [structType,unionType])
@@ -2059,6 +2057,9 @@ if space <> fieldListSpace then begin   {are we defining a function?}
          or (globalTable <> table) then
          if (not doingParameters) or (cs^.state <> declared) then
             Error(42);
+      if itype <> nil then
+         if cs^.itype <> nil then
+            itype := MakeCompositeType(cs^.itype, itype);
       p := cs;
       needSymbol := false;
       end; {if}
@@ -2072,6 +2073,9 @@ if class = staticsy then                {statics go in the global symbol table}
                or ((cs^.state = defined) and (state <> initialized))
                or (cs^.state = initialized) then
                Error(42);
+            if itype <> nil then
+               if cs^.itype <> nil then
+                  itype := MakeCompositeType(cs^.itype, itype);
             p := cs;
             needSymbol := false;
             end; {if}
diff --git a/cc.notes b/cc.notes
index f998f6e..397573a 100644
--- a/cc.notes
+++ b/cc.notes
@@ -1962,6 +1962,8 @@ int foo(int[42]);
 
 216. Preprocessing directive names could be subject to macro replacement, potentially altering their behavior (e.g. due to a definition like "#define ifdef ifndef").  Now directive names are not expanded as macros, even if there is a macro of the same name.
 
+217. If there were multiple declarations of a variable with internal or external linkage, only the type from the latest declaration would be used, rather than properly forming the composite type from the various declarations.  If a global array was first declared with a size specified and subsequently redeclared without a size, this could cause the proper storage not to be allocated for it.
+
 -- Bugs from C 2.1.0 that have been fixed -----------------------------------
 
 1.  In some situations, fread() reread the first 1K or so of the file.