runtime: eliminate va_list from kernel interface.

artiq/compiler/transforms/llvm_ir_generator.py

@@ -19,6 +19,7 @@ lli32      = ll.IntType(32)
 lli64      = ll.IntType(64)
 lldouble   = ll.DoubleType()
 llptr      = ll.IntType(8).as_pointer()
+llptrptr   = ll.IntType(8).as_pointer().as_pointer()
 llmetadata = ll.MetaData()
 
 
@@ -349,8 +350,7 @@ class LLVMIRGenerator:
         elif name == "strcmp":
             llty = ll.FunctionType(lli32, [llptr, llptr])
         elif name == "send_rpc":
-            llty = ll.FunctionType(llvoid, [lli32, llptr],
-                                   var_arg=True)
+            llty = ll.FunctionType(llvoid, [lli32, llptr, llptrptr])
         elif name == "recv_rpc":
             llty = ll.FunctionType(lli32, [llptr])
         elif name == "now":
@@ -1233,7 +1233,8 @@ class LLVMIRGenerator:
         llstackptr = self.llbuilder.call(self.llbuiltin("llvm.stacksave"), [],
                                          name="rpc.stack")
 
-        llargs = []
+        llargs = self.llbuilder.alloca(llptr, ll.Constant(lli32, len(args)),
+                                       name="rpc.args")
         for index, arg in enumerate(args):
             if builtins.is_none(arg.type):
                 llargslot = self.llbuilder.alloca(ll.LiteralStructType([]),
@@ -1243,10 +1244,13 @@ class LLVMIRGenerator:
                 llargslot = self.llbuilder.alloca(llarg.type,
                                                   name="rpc.arg{}".format(index))
                 self.llbuilder.store(llarg, llargslot)
-            llargs.append(llargslot)
+            llargslot = self.llbuilder.bitcast(llargslot, llptr)
+
+            llargptr = self.llbuilder.gep(llargs, [ll.Constant(lli32, index)])
+            self.llbuilder.store(llargslot, llargptr)
 
         self.llbuilder.call(self.llbuiltin("send_rpc"),
-                            [llservice, lltag] + llargs)
+                            [llservice, lltag, llargs])
 
         # Don't waste stack space on saved arguments.
         self.llbuilder.call(self.llbuiltin("llvm.stackrestore"), [llstackptr])

artiq/runtime/ksupport.c

@@ -272,13 +272,19 @@ double sqrt(double x)
 /* called by libunwind */
 int fprintf(FILE *stream, const char *fmt, ...)
 {
-    struct msg_log request;
+    va_list args;
+    va_start(args, fmt);
 
+    char buf[256];
+    int len = vscnprintf(buf, sizeof(buf), fmt, args);
+
+    va_end(args);
+
+    struct msg_log request;
     request.type = MESSAGE_TYPE_LOG;
-    request.fmt = fmt;
-    va_start(request.args, fmt);
+    request.buf = buf;
+    request.len = len;
     mailbox_send_and_wait(&request);
-    va_end(request.args);
 
     return 0;
 }
@@ -462,7 +468,7 @@ void watchdog_clear(int id)
     mailbox_send_and_wait(&request);
 }
 
-void send_rpc(int service, const char *tag, ...)
+void send_rpc(int service, const char *tag, void **data)
 {
     struct msg_rpc_send request;
 
@@ -472,9 +478,8 @@ void send_rpc(int service, const char *tag, ...)
         request.type = MESSAGE_TYPE_RPC_BATCH;
     request.service = service;
     request.tag = tag;
-    va_start(request.args, tag);
+    request.data = data;
     mailbox_send_and_wait(&request);
-    va_end(request.args);
 }
 
 int recv_rpc(void *slot)
@@ -537,7 +542,12 @@ void attribute_writeback(void *utypes)
 
                 if(attr->tag) {
                     uintptr_t value = (uintptr_t)object + attr->offset;
-                    send_rpc(0, attr->tag, &object, &attr->name, value);
+                    void *args[] = {
+                        &object,
+                        &attr->name,
+                        (void*)value
+                    };
+                    send_rpc(0, attr->tag, args);
                 }
             }
         }
@@ -590,11 +600,17 @@ void cache_put(const char *key, struct artiq_list value)
 
 void core_log(const char *fmt, ...)
 {
-    struct msg_log request;
+    va_list args;
+    va_start(args, fmt);
 
+    char buf[256];
+    int len = vscnprintf(buf, sizeof(buf), fmt, args);
+
+    va_end(args);
+
+    struct msg_log request;
     request.type = MESSAGE_TYPE_LOG;
-    request.fmt = fmt;
-    va_start(request.args, fmt);
+    request.buf = buf;
+    request.len = len;
     mailbox_send_and_wait(&request);
-    va_end(request.args);
 }

artiq/runtime/ksupport.h

@@ -8,7 +8,7 @@ struct artiq_list {
 
 int watchdog_set(int ms);
 void watchdog_clear(int id);
-void send_rpc(int service, const char *tag, ...);
+void send_rpc(int service, const char *tag, void **data);
 int recv_rpc(void *slot);
 struct artiq_list cache_get(const char *key);
 void cache_put(const char *key, struct artiq_list value);

artiq/runtime/messages.h

@@ -79,7 +79,7 @@ struct msg_rpc_send {
     int type;
     int service;
     const char *tag;
-    va_list args;
+    void **data;
 };
 
 struct msg_rpc_recv_request {
@@ -118,8 +118,8 @@ struct msg_cache_put_reply {
 
 struct msg_log {
     int type;
-    const char *fmt;
-    va_list args;
+    const char *buf;
+    size_t len;
 };
 
 #endif /* __MESSAGES_H */

artiq/runtime/session.c

@@ -893,13 +893,13 @@ static int send_rpc_value(const char **tag, void **value)
     return 1;
 }
 
-static int send_rpc_request(int service, const char *tag, va_list args)
+static int send_rpc_request(int service, const char *tag, void **data)
 {
     out_packet_start(REMOTEMSG_TYPE_RPC_REQUEST);
     out_packet_int32(service);
 
     while(*tag != ':') {
-        void *value = va_arg(args, void*);
+        void *value = *data++;
         if(!kloader_validate_kpointer(value))
             return 0;
         if(!send_rpc_value(&tag, &value))
@@ -994,7 +994,7 @@ static int process_kmsg(struct msg_base *umsg)
         case MESSAGE_TYPE_RPC_BATCH: {
             struct msg_rpc_send *msg = (struct msg_rpc_send *)umsg;
 
-            if(!send_rpc_request(msg->service, msg->tag, msg->args)) {
+            if(!send_rpc_request(msg->service, msg->tag, msg->data)) {
                 core_log("Failed to send RPC request (service %d, tag %s)\n",
                          msg->service, msg->tag);
                 return 0; // restart session