From: Philippe Mathieu-Daudé Date: Thu, 18 Mar 2021 16:30:59 +0000 (+0100) Subject: hw/intc/i8259: Refactor pic_read_irq() to avoid uninitialized variable X-Git-Tag: v6.0.0-rc0~13^2~1 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=52ad57a9b68e215c4f5fa2cfd2412132b522bff5;p=thirdparty%2Fqemu.git hw/intc/i8259: Refactor pic_read_irq() to avoid uninitialized variable Some compiler versions are smart enough to detect a potentially uninitialized variable, but are not smart enough to detect that this cannot happen due to the code flow: ../hw/intc/i8259.c: In function ‘pic_read_irq’: ../hw/intc/i8259.c:203:13: error: ‘irq2’ may be used uninitialized in this function [-Werror=maybe-uninitialized] 203 | irq = irq2 + 8; | ~~~~^~~~~~~~~~ Restrict irq2 variable use to the inner statement. Fixes: 78ef2b6989f ("i8259: Reorder intack in pic_read_irq") Reported-by: Christian Borntraeger Signed-off-by: Philippe Mathieu-Daudé Message-Id: <20210318163059.3686596-1-philmd@redhat.com> Signed-off-by: Paolo Bonzini --- diff --git a/hw/intc/i8259.c b/hw/intc/i8259.c index 344fd04db14..cc4e21ffec0 100644 --- a/hw/intc/i8259.c +++ b/hw/intc/i8259.c @@ -176,10 +176,12 @@ static void pic_intack(PICCommonState *s, int irq) int pic_read_irq(DeviceState *d) { PICCommonState *s = PIC_COMMON(d); - int irq, irq2, intno; + int irq, intno; irq = pic_get_irq(s); if (irq >= 0) { + int irq2; + if (irq == 2) { irq2 = pic_get_irq(slave_pic); if (irq2 >= 0) { @@ -189,20 +191,18 @@ int pic_read_irq(DeviceState *d) irq2 = 7; } intno = slave_pic->irq_base + irq2; + pic_intack(s, irq); + irq = irq2 + 8; } else { intno = s->irq_base + irq; + pic_intack(s, irq); } - pic_intack(s, irq); } else { /* spurious IRQ on host controller */ irq = 7; intno = s->irq_base + irq; } - if (irq == 2) { - irq = irq2 + 8; - } - #ifdef DEBUG_IRQ_LATENCY printf("IRQ%d latency=%0.3fus\n", irq,