From 4bc83ac3933efa565ae3326b55fcd711b63c073d Mon Sep 17 00:00:00 2001
From: mingodad <mingodad@gmail.com>
Date: Wed, 26 Mar 2014 20:14:39 +0000
Subject: 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 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

(limited to 'tccgen.c')

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 ? */
-- 
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