Bugfix: 32-bit vs 64-bit bug in x86_64-gen.c:gcall_or_jmp

Verify an immediate value fits into 32 bits before jumping to it/calling it with a 32-bit immediate operand. Without this fix, code along the lines of ((int (*)(const char *, ...))140244834372944LL)("hi\n"); will fail mysteriously, even if that decimal constant is the correct address for printf. See https://github.com/pipcet/tinycc/tree/bugfix-1

Philip committed 11 years ago

Commit aacf65b1 parent b08ce881 file · +2 −1Browse files

Unified · Split

x86_64-gen.c+2−1

@@ -600,7 +600,8 @@ void store(int r, SValue *v) · 599 unmodified lines
600	600	static void gcall_or_jmp(int is_jmp)
601	601	{
602	602	int r;
603		− if ((vtop->r & (VT_VALMASK \| VT_LVAL)) == VT_CONST) {
	603	+ if ((vtop->r & (VT_VALMASK \| VT_LVAL)) == VT_CONST &&
	604	+ ((vtop->r & VT_SYM) \|\| (vtop->c.ll-4) == (int)(vtop->c.ll-4))) {
604	605	/* constant case */
605	606	if (vtop->r & VT_SYM) {
606	607	/* relocation case */