Implement C99 scope rules for selection and iteration statements.

Under these rules, if, switch, for, while, and do statements each have their own block scopes separate from the enclosing scope, and their substatements also have their own block scopes.

This patch always applies the C99 scope rules, but a flag can be changed to disable them or make them conditional on a configuration setting.

Parser.pas

@@ -82,6 +82,7 @@ implementation
 const
    maxBitField = 32;                    {max # of bits in a bit field}
    allowMixedDeclarations = true;
+   c99Scope = true;
  
 type
 
@@ -569,6 +570,8 @@ var
    stPtr^.doLab := lab;
    stPtr^.breakLab := 0;
    stPtr^.continueLab := 0;
+   if c99Scope then PushTable;
+   if c99Scope then PushTable;
    Statement;                           {process the first loop body statement}
    end; {DoStatement}
 
@@ -598,6 +601,7 @@ var
    stPtr^.continueLab := continueLab;
    stPtr^.breakLab := breakLab;
 
+   if c99Scope then PushTable;
    Match(lparench,13);                  {evaluate the start condition}
    if token.kind <> semicolonch then begin
       Expression(normalExpression, [semicolonch]);
@@ -639,6 +643,7 @@ var
    stPtr^.e3List := tl;                 {save the list}
    Match(rparench,12);                  {get the closing for loop paren}
 
+   if c99Scope then PushTable;
    Statement;                           {process the first loop body statement}
    end; {ForStatement}
 
@@ -654,6 +659,7 @@ var
  
    begin {IfStatement}
    NextToken;                           {skip the 'if' token}
+   if c99Scope then PushTable;
    Match(lparench, 13);                 {evaluate the condition}
    Expression(normalExpression, [rparench]);
    Match(rparench, 12);
@@ -667,6 +673,7 @@ var
    statementList := stPtr;
    stPtr^.kind := ifSt;
    stPtr^.ifLab := lab;
+   if c99Scope then PushTable;
    Statement;                           {process the 'true' statement}
    end; {IfStatement}
 
@@ -767,6 +774,7 @@ var
    stPtr^.breakLab := stPtr^.switchExit;
    stPtr^.switchList := nil;
    stPtr^.switchDefault := 0;
+   if c99Scope then PushTable;
    Match(lparench, 13);                 {evaluate the condition}
    Expression(normalExpression,[rparench]);
    Match(rparench, 12);
@@ -802,6 +810,7 @@ var
          Error(71);
       end; {case}
    Gen1(pc_ujp, stPtr^.switchLab);      {branch to the xjp instruction}
+   if c99Scope then PushTable;
    Statement;                           {process the loop body statement}
    end; {SwitchStatement}
 
@@ -828,11 +837,13 @@ var
    stPtr^.breakLab := endl;
    stPtr^.continueLab := top;
    Gen1(dc_lab, top);                   {define the top label}
+   if c99Scope then PushTable;
    Match(lparench, 13);                 {evaluate the condition}
    Expression(normalExpression, [rparench]);
    Match(rparench, 12);
    CompareToZero(pc_neq);               {evaluate the condition}
    Gen1(pc_fjp, endl);
+   if c99Scope then PushTable;
    Statement;                           {process the first loop body statement}
    end; {WhileStatement}
 
@@ -897,6 +908,7 @@ var
    stPtr: statementPtr;                 {work pointer}
 
 begin {EndDoStatement}
+if c99Scope then PopTable;
 stPtr := statementList;                 {get the statement record}
 if token.kind = whilesy then begin      {if a while clause exists, process it}
    NextToken;                           {skip the 'while' token}
@@ -915,6 +927,7 @@ if stPtr^.breakLab <> 0 then            {create the break label}
    Gen1(dc_lab, stPtr^.breakLab);
 statementList := stPtr^.next;           {pop the statement record}
 dispose(stPtr);
+if c99Scope then PopTable;
 end; {EndDoStatement}
 
 
@@ -927,6 +940,7 @@ var
    stPtr: statementPtr;                 {work pointer}
 
 begin {EndIfStatement}
+if c99Scope then PopTable;
 stPtr := statementList;                 {get the label to branch to}
 lab1 := stPtr^.ifLab;
 statementList := stPtr^.next;           {pop the statement record}
@@ -942,10 +956,13 @@ if token.kind = elsesy then begin       {if an else clause exists, process it}
    statementList := stPtr;
    stPtr^.kind := elseSt;
    stPtr^.elseLab := lab2;
+   if c99Scope then PushTable;
    Statement;                           {evaluate the else clause}
    end {if}
-else
+else begin
    Gen1(dc_lab, lab1);                  {create label for if to branch to}
+   if c99Scope then PopTable;
+   end; {else}
 end; {EndIfStatement}
 
 
@@ -957,10 +974,12 @@ var
    stPtr: statementPtr;                 {work pointer}
 
 begin {EndElseStatement}
+if c99Scope then PopTable;
 stPtr := statementList;                 {create the label to branch to}
 Gen1(dc_lab, stPtr^.elseLab);
 statementList := stPtr^.next;           {pop the statement record}
 dispose(stPtr);
+if c99Scope then PopTable;
 end; {EndElseStatement}
 
 
@@ -975,6 +994,7 @@ var
    lPrintMacroExpansions: boolean;      {local copy of printMacroExpansions}
 
 begin {EndForStatement}
+if c99Scope then PopTable;
 stPtr := statementList;
 Gen1(dc_lab, stPtr^.continueLab);       {define the continue label}
 
@@ -1003,6 +1023,7 @@ Gen1(pc_ujp, stPtr^.forLoop);           {loop to the test}
 Gen1(dc_lab, stPtr^.breakLab);          {create the exit label}
 statementList := stPtr^.next;           {pop the statement record}
 dispose(stPtr);
+if c99Scope then PopTable;
 end; {EndForStatement}
 
 
@@ -1026,6 +1047,7 @@ var
    swPtr,swPtr2: switchPtr;             {switch label table list}
 
 begin {EndSwitchStatement}
+if c99Scope then PopTable;
 stPtr := statementList;                 {get the statement record}
 exitLab := stPtr^.switchExit;           {get the exit label}
 isLong := stPtr^.isLong;                {get the long flag}
@@ -1095,6 +1117,7 @@ else begin
 FreeTemp(stPtr^.ln, stPtr^.size);       {release temp variable}
 statementList := stPtr^.next;           {pop the statement record}
 dispose(stPtr);
+if c99Scope then PopTable;
 end; {EndSwitchStatement}
 
 
@@ -1106,11 +1129,13 @@ var
    stPtr: statementPtr;                 {work pointer}
 
 begin {EndWhileStatement}
+if c99Scope then PopTable;
 stPtr := statementList;                 {loop to the test}
 Gen1(pc_ujp, stPtr^.whileTop);
 Gen1(dc_lab, stPtr^.whileEnd);          {create the exit label}
 statementList := stPtr^.next;           {pop the statement record}
 dispose(stPtr);
+if c99Scope then PopTable;
 end; {EndWhileStatement}
 
 {-- Type declarations ------------------------------------------}