[libvirt] [PATCH] conf: don't use virDomainVirtType in struct field

[Daniel P. Berrangé]

Use of enum types for struct fields is generally avoided since it causes
warnings if the compiler assumes the enum is unsigned. For example

  commit 8e2982b5767a25e5da6533c65bfdc648c95b3c69
  Author: Cole Robinson <crobinso at redhat.com>
  Date:   Tue Jul 24 16:27:54 2018 -0400

    conf: Clean up virDomainDefParseCaps

Introduced a line:

  if ((def->virtType = virDomainVirtTypeFromString(virttype)) < 0) {

which causes a build failure with CLang

  conf/domain_conf.c:19143:65: error: comparison of unsigned enum expression < 0 is always false [-Werror,-Wtautological-compare]

as the compiler is free to optimize away the "< 0" check due to the
assumption that the enum type is unsigned and always in range.

Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
---
 src/conf/domain_conf.c  | 2 +-
 src/conf/domain_conf.h  | 2 +-
 src/qemu/qemu_command.c | 2 +-
 src/qemu/qemu_process.c | 4 +++-
 4 files changed, 6 insertions(+), 4 deletions(-)

Pushing as a build fix for CLang


diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index c27c874d9e..f94a90fbcc 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -15075,7 +15075,7 @@ virDomainVideoDefaultRAM(const virDomainDef *def,
 int
 virDomainVideoDefaultType(const virDomainDef *def)
 {
-    switch (def->virtType) {
+    switch ((virDomainVirtType)def->virtType) {
     case VIR_DOMAIN_VIRT_TEST:
     case VIR_DOMAIN_VIRT_XEN:
         if (def->os.type == VIR_DOMAIN_OSTYPE_XEN ||
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index a804e86f6c..c1dfa37fdf 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -2386,7 +2386,7 @@ struct _virDomainVirtioOptions {
 typedef struct _virDomainDef virDomainDef;
 typedef virDomainDef *virDomainDefPtr;
 struct _virDomainDef {
-    virDomainVirtType virtType;
+    int virtType; /* enum virDomainVirtType */
     int id;
     unsigned char uuid[VIR_UUID_BUFLEN];
 
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index ae45c45b7f..d148db90fa 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -7163,7 +7163,7 @@ qemuBuildMachineCommandLine(virCommandPtr cmd,
     virCommandAddArg(cmd, "-machine");
     virBufferAdd(&buf, def->os.machine, -1);
 
-    switch (def->virtType) {
+    switch ((virDomainVirtType)def->virtType) {
     case VIR_DOMAIN_VIRT_QEMU:
         virBufferAddLit(&buf, ",accel=tcg");
         break;
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 27bd8b9465..c4e33723d1 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -7191,6 +7191,7 @@ int qemuProcessAttach(virConnectPtr conn ATTRIBUTE_UNUSED,
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
     virCapsPtr caps = NULL;
     bool active = false;
+    virDomainVirtType virtType;
 
     VIR_DEBUG("Beginning VM attach process");
 
@@ -7342,8 +7343,9 @@ int qemuProcessAttach(virConnectPtr conn ATTRIBUTE_UNUSED,
         goto exit_monitor;
     if (qemuMonitorGetStatus(priv->mon, &running, &reason) < 0)
         goto exit_monitor;
-    if (qemuMonitorGetVirtType(priv->mon, &vm->def->virtType) < 0)
+    if (qemuMonitorGetVirtType(priv->mon, &virtType) < 0)
         goto exit_monitor;
+    vm->def->virtType = virtType;
     if (qemuDomainObjExitMonitor(driver, vm) < 0)
         goto error;
 
-- 
2.17.1