test: fix usdt undeclared function errors on mantis

Recently usage of undeclared functions became an error rather than a
warning, in C2x. https://reviews.llvm.org/D122983?id=420290

This change has migrated into the build tools of Ubuntu 23.10 which now
causes the USDT tests to fail to compile, see
bitcoin/bitcoin#28600

Fix this by setting `-Wno-error=implicit-function-declaration` for the
tracing programs.

test/functional/interface_usdt_coinselection.py

@@ -166,7 +166,7 @@ def run_test(self):
         ctx.enable_probe(probe="coin_selection:normal_create_tx_internal", fn_name="trace_normal_create_tx")
         ctx.enable_probe(probe="coin_selection:attempting_aps_create_tx", fn_name="trace_attempt_aps")
         ctx.enable_probe(probe="coin_selection:aps_create_tx_internal", fn_name="trace_aps_create_tx")
-        self.bpf = BPF(text=coinselection_tracepoints_program, usdt_contexts=[ctx], debug=0)
+        self.bpf = BPF(text=coinselection_tracepoints_program, usdt_contexts=[ctx], debug=0, cflags=["-Wno-error=implicit-function-declaration"])
 
         self.log.info("Prepare wallets")
         self.generate(self.nodes[0], 101)

test/functional/interface_usdt_mempool.py

@@ -119,6 +119,7 @@
   replaced_events.perf_submit(ctx, &replaced, sizeof(replaced));
   return 0;
 }
+
 """
 
 
@@ -143,7 +144,7 @@ def added_test(self):
         node = self.nodes[0]
         ctx = USDT(pid=node.process.pid)
         ctx.enable_probe(probe="mempool:added", fn_name="trace_added")
-        bpf = BPF(text=MEMPOOL_TRACEPOINTS_PROGRAM, usdt_contexts=[ctx], debug=0)
+        bpf = BPF(text=MEMPOOL_TRACEPOINTS_PROGRAM, usdt_contexts=[ctx], debug=0, cflags=["-Wno-error=implicit-function-declaration"])
 
         def handle_added_event(_, data, __):
             events.append(bpf["added_events"].event(data))
@@ -180,7 +181,7 @@ def removed_test(self):
         node = self.nodes[0]
         ctx = USDT(pid=node.process.pid)
         ctx.enable_probe(probe="mempool:removed", fn_name="trace_removed")
-        bpf = BPF(text=MEMPOOL_TRACEPOINTS_PROGRAM, usdt_contexts=[ctx], debug=0)
+        bpf = BPF(text=MEMPOOL_TRACEPOINTS_PROGRAM, usdt_contexts=[ctx], debug=0, cflags=["-Wno-error=implicit-function-declaration"])
 
         def handle_removed_event(_, data, __):
             events.append(bpf["removed_events"].event(data))
@@ -226,7 +227,7 @@ def replaced_test(self):
         node = self.nodes[0]
         ctx = USDT(pid=node.process.pid)
         ctx.enable_probe(probe="mempool:replaced", fn_name="trace_replaced")
-        bpf = BPF(text=MEMPOOL_TRACEPOINTS_PROGRAM, usdt_contexts=[ctx], debug=0)
+        bpf = BPF(text=MEMPOOL_TRACEPOINTS_PROGRAM, usdt_contexts=[ctx], debug=0, cflags=["-Wno-error=implicit-function-declaration"])
 
         def handle_replaced_event(_, data, __):
             events.append(bpf["replaced_events"].event(data))
@@ -277,7 +278,7 @@ def rejected_test(self):
         self.log.info("Hooking into mempool:rejected tracepoint...")
         ctx = USDT(pid=node.process.pid)
         ctx.enable_probe(probe="mempool:rejected", fn_name="trace_rejected")
-        bpf = BPF(text=MEMPOOL_TRACEPOINTS_PROGRAM, usdt_contexts=[ctx], debug=0)
+        bpf = BPF(text=MEMPOOL_TRACEPOINTS_PROGRAM, usdt_contexts=[ctx], debug=0, cflags=["-Wno-error=implicit-function-declaration"])
 
         def handle_rejected_event(_, data, __):
             events.append(bpf["rejected_events"].event(data))

test/functional/interface_usdt_net.py

@@ -114,7 +114,7 @@ def __repr__(self):
                          fn_name="trace_inbound_message")
         ctx.enable_probe(probe="net:outbound_message",
                          fn_name="trace_outbound_message")
-        bpf = BPF(text=net_tracepoints_program, usdt_contexts=[ctx], debug=0)
+        bpf = BPF(text=net_tracepoints_program, usdt_contexts=[ctx], debug=0, cflags=["-Wno-error=implicit-function-declaration"])
 
         EXPECTED_INOUTBOUND_VERSION_MSG = 1
         checked_inbound_version_msg = 0

test/functional/interface_usdt_utxocache.py

@@ -175,7 +175,7 @@ def test_uncache(self):
         ctx = USDT(pid=self.nodes[0].process.pid)
         ctx.enable_probe(probe="utxocache:uncache",
                          fn_name="trace_utxocache_uncache")
-        bpf = BPF(text=utxocache_changes_program, usdt_contexts=[ctx], debug=0)
+        bpf = BPF(text=utxocache_changes_program, usdt_contexts=[ctx], debug=0, cflags=["-Wno-error=implicit-function-declaration"])
 
         # The handle_* function is a ctypes callback function called from C. When
         # we assert in the handle_* function, the AssertError doesn't propagate
@@ -244,7 +244,7 @@ def test_add_spent(self):
         ctx.enable_probe(probe="utxocache:add", fn_name="trace_utxocache_add")
         ctx.enable_probe(probe="utxocache:spent",
                          fn_name="trace_utxocache_spent")
-        bpf = BPF(text=utxocache_changes_program, usdt_contexts=[ctx], debug=0)
+        bpf = BPF(text=utxocache_changes_program, usdt_contexts=[ctx], debug=0, cflags=["-Wno-error=implicit-function-declaration"])
 
         # The handle_* function is a ctypes callback function called from C. When
         # we assert in the handle_* function, the AssertError doesn't propagate
@@ -333,7 +333,7 @@ def test_flush(self):
         ctx = USDT(pid=self.nodes[0].process.pid)
         ctx.enable_probe(probe="utxocache:flush",
                          fn_name="trace_utxocache_flush")
-        bpf = BPF(text=utxocache_flushes_program, usdt_contexts=[ctx], debug=0)
+        bpf = BPF(text=utxocache_flushes_program, usdt_contexts=[ctx], debug=0, cflags=["-Wno-error=implicit-function-declaration"])
 
         # The handle_* function is a ctypes callback function called from C. When
         # we assert in the handle_* function, the AssertError doesn't propagate
@@ -390,7 +390,7 @@ def handle_utxocache_flush(_, data, __):
         ctx = USDT(pid=self.nodes[0].process.pid)
         ctx.enable_probe(probe="utxocache:flush",
                          fn_name="trace_utxocache_flush")
-        bpf = BPF(text=utxocache_flushes_program, usdt_contexts=[ctx], debug=0)
+        bpf = BPF(text=utxocache_flushes_program, usdt_contexts=[ctx], debug=0, cflags=["-Wno-error=implicit-function-declaration"])
         bpf["utxocache_flush"].open_perf_buffer(handle_utxocache_flush)
 
         self.log.info(f"prune blockchain to trigger a flush for pruning")

test/functional/interface_usdt_validation.py

@@ -94,7 +94,7 @@ def __repr__(self):
         ctx.enable_probe(probe="validation:block_connected",
                          fn_name="trace_block_connected")
         bpf = BPF(text=validation_blockconnected_program,
-                  usdt_contexts=[ctx], debug=0)
+                  usdt_contexts=[ctx], debug=0, cflags=["-Wno-error=implicit-function-declaration"])
 
         def handle_blockconnected(_, data, __):
             event = ctypes.cast(data, ctypes.POINTER(Block)).contents