From 4bc83ac3933efa565ae3326b55fcd711b63c073d Mon Sep 17 00:00:00 2001
From: mingodad <mingodad@gmail.com>
Date: Wed, 26 Mar 2014 20:14:39 +0000
Subject: [PATCH] After several days searching why my code refactoring to
 remove globals was crashing, I found the problem it was because CValue stack
 variables have rubish as it inital values and assigning to a member that is
 smaller than the big union item and trying to recover it later as a different
 member gives bak garbage.

ST_FUNC void vset(TCCState* tcc_state, CType *type, int r, int v)
{
    CValue cval;
    memset(&cval, 0, sizeof(CValue));

    cval.i = v; //,<<<<<<<<<<< here is the main bug that mix with garbage
    vsetc(tcc_state, type, r, &cval);
}

/* store a value or an expression directly in global data or in local array */
static void init_putv(TCCState* tcc_state, CType *type, Section *sec, unsigned long c,
                      int v, int expr_type)
{
...
        case VT_PTR:
            if (tcc_state->tccgen_vtop->r & VT_SYM) {
                greloc(tcc_state, sec, tcc_state->tccgen_vtop->sym, c, R_DATA_PTR);
            }

//<<< on the next line is where we try to get the assigned value to cvalue.i as cvalue.ull

            *(addr_t *)ptr |= (tcc_state->tccgen_vtop->c.ull & bit_mask) << bit_pos;
            break;

Also this patch makes vla tests pass on linux 32 bits
---
 tccgen.c |  9 ++++++++-
 tccpp.c  | 16 ++++++++++++----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/tccgen.c b/tccgen.c
index 9c12c92..b4f97f4 100644
--- a/tccgen.c
+++ b/tccgen.c
@@ -329,6 +329,7 @@ static void vsetc(CType *type, int r, CValue *vc)
 void vpush(CType *type)
 {
     CValue cval;
+    memset(&cval, 0, sizeof(CValue));
     vsetc(type, VT_CONST, &cval);
 }
 
@@ -336,6 +337,7 @@ void vpush(CType *type)
 ST_FUNC void vpushi(int v)
 {
     CValue cval;
+    memset(&cval, 0, sizeof(CValue));
     cval.i = v;
     vsetc(&int_type, VT_CONST, &cval);
 }
@@ -344,6 +346,7 @@ ST_FUNC void vpushi(int v)
 static void vpushs(long long v)
 {
   CValue cval;
+  memset(&cval, 0, sizeof(CValue));
   if (PTR_SIZE == 4)
     cval.i = (int)v;
   else
@@ -354,8 +357,9 @@ static void vpushs(long long v)
 /* push arbitrary 64bit constant */
 void vpush64(int ty, unsigned long long v)
 {
-    CValue cval;
     CType ctype;
+    CValue cval;
+    memset(&cval, 0, sizeof(CValue));
     ctype.t = ty;
     ctype.ref = NULL;
     cval.ull = v;
@@ -372,6 +376,7 @@ static inline void vpushll(long long v)
 static inline void vpushsym(CType *type, Sym *sym)
 {
     CValue cval;
+    memset(&cval, 0, sizeof(CValue));
 
     cval.ull = 0;
     vsetc(type, VT_CONST | VT_SYM, &cval);
@@ -446,6 +451,7 @@ ST_FUNC void vpush_global_sym(CType *type, int v)
 ST_FUNC void vset(CType *type, int r, int v)
 {
     CValue cval;
+    memset(&cval, 0, sizeof(CValue));
 
     cval.i = v;
     vsetc(type, r, &cval);
@@ -731,6 +737,7 @@ ST_FUNC int gv(int rc)
             unsigned long offset;
 #if defined(TCC_TARGET_ARM) && !defined(TCC_ARM_VFP)
             CValue check;
+            memset(&check, 0, sizeof(CValue));
 #endif
             
             /* XXX: unify with initializers handling ? */
diff --git a/tccpp.c b/tccpp.c
index cf1fc65..2609ad7 100644
--- a/tccpp.c
+++ b/tccpp.c
@@ -936,6 +936,7 @@ static void tok_str_add2(TokenString *s, int t, CValue *cv)
 ST_FUNC void tok_str_add_tok(TokenString *s)
 {
     CValue cval;
+    memset(&cval, 0, sizeof(CValue));
 
     /* save line number info */
     if (file->line_num != s->last_line_num) {
@@ -999,8 +1000,9 @@ static inline void TOK_GET(int *t, const int **pp, CValue *cv)
 static int macro_is_equal(const int *a, const int *b)
 {
     char buf[STRING_MAX_SIZE + 1];
-    CValue cv;
     int t;
+    CValue cv;
+    memset(&cv, 0, sizeof(CValue));
     while (*a && *b) {
         TOK_GET(&t, &a, &cv);
         pstrcpy(buf, sizeof buf, get_tok_str(t, &cv));
@@ -1159,6 +1161,7 @@ static void tok_print(int *str)
 {
     int t;
     CValue cval;
+    memset(&cval, 0, sizeof(CValue));
 
     printf("<");
     while (1) {
@@ -2525,9 +2528,10 @@ static int *macro_arg_subst(Sym **nested_list, const int *macro_str, Sym *args)
     int last_tok, t, spc;
     const int *st;
     Sym *s;
-    CValue cval;
     TokenString str;
     CString cstr;
+    CValue cval;
+    memset(&cval, 0, sizeof(CValue));
 
     tok_str_new(&str);
     last_tok = 0;
@@ -2629,9 +2633,10 @@ static int macro_subst_tok(TokenString *tok_str,
     const int *p;
     TokenString str;
     char *cstrval;
-    CValue cval;
     CString cstr;
     char buf[32];
+    CValue cval;
+    memset(&cval, 0, sizeof(CValue));
     
     /* if symbol is a macro, prepare substitution */
     /* special macros */
@@ -2806,6 +2811,7 @@ static inline int *macro_twosharps(const int *macro_str)
     /* we search the first '##' */
     for(ptr = macro_str;;) {
         CValue cval;
+        memset(&cval, 0, sizeof(CValue));
         TOK_GET(&t, &ptr, &cval);
         if (t == TOK_TWOSHARPS)
             break;
@@ -2836,6 +2842,7 @@ static inline int *macro_twosharps(const int *macro_str)
                 t = *++ptr;
             if (t && t != TOK_TWOSHARPS) {
                 CValue cval;
+                memset(&cval, 0, sizeof(CValue));
                 TOK_GET(&t, &ptr, &cval);
                 /* We concatenate the two tokens */
                 cstr_new(&cstr);
@@ -2877,9 +2884,10 @@ static void macro_subst(TokenString *tok_str, Sym **nested_list,
     int *macro_str1;
     const int *ptr;
     int t, ret, spc;
-    CValue cval;
     struct macro_level ml;
     int force_blank;
+    CValue cval;
+    memset(&cval, 0, sizeof(CValue));
     
     /* first scan for '##' operator handling */
     ptr = macro_str;