Enable tracer support. Resolves #97

CMakeLists.txt

@@ -86,7 +86,7 @@ if(EMSCRIPTEN)
 elseif(WASIENV)
 
   if(BUILD_WASI_SUPPORT)
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Dd_m3HasMetaWASI")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Dd_m3HasMetaWASI -Dd_m3HasTracer")
   endif()
 
   set(CMAKE_C_FLAGS_RELEASE "-O3 -Wfatal-errors -fomit-frame-pointer -fno-stack-check -fno-stack-protector")
@@ -127,7 +127,7 @@ elseif(WIN32)
 else()
 
   if(BUILD_WASI_SUPPORT)
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Dd_m3HasWASI") #-Dd_m3FixedHeap=1048576
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Dd_m3HasWASI -Dd_m3HasTracer") #-Dd_m3FixedHeap=1048576
   endif()
 
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Wparentheses -Wundef -Wpointer-arith -Wstrict-aliasing=2")

platforms/app/main.c

@@ -13,6 +13,7 @@
 #include "wasm3.h"
 #include "m3_api_wasi.h"
 #include "m3_api_libc.h"
+#include "m3_api_tracer.h"
 #include "m3_env.h"
 
 #define FATAL(msg, ...) { printf("Error: [Fatal] " msg "\n", ##__VA_ARGS__); goto _onfatal; }
@@ -265,6 +266,11 @@ int  main  (int i_argc, const char* i_argv[])
         if (result) FATAL("m3_LinkWASI: %s", result);
 #endif
 
+#if defined(d_m3HasTracer)
+        result = m3_LinkTracer (runtime->modules);
+        if (result) FATAL("m3_LinkTracer: %s", result);
+#endif
+
         result = m3_LinkLibC (runtime->modules);
         if (result) FATAL("m3_LinkLibC: %s", result);
 

source/m3_api_tracer.c

@@ -14,7 +14,7 @@
 #if defined(d_m3HasTracer)
 
 
-static FILE* trace;
+static FILE* trace = NULL;
 
 m3ApiRawFunction(m3_env_log_execution)
 {
@@ -114,10 +114,15 @@ d_m3TraceLocal(set_f64, "set f64", double,  "%lf")
 static
 M3Result SuppressLookupFailure(M3Result i_result)
 {
-    if (i_result == m3Err_functionLookupFailed)
-        return m3Err_none;
-    else
-        return i_result;
+    if (i_result == m3Err_none) {
+        // If any trace function is found in the module, open the trace file
+        if (!trace) {
+            trace = fopen ("wasm3_trace.csv","w");
+        }
+    } else if (i_result == m3Err_functionLookupFailed) {
+        i_result = m3Err_none;
+    }
+    return i_result;
 }
 
 
@@ -127,8 +132,6 @@ M3Result  m3_LinkTracer  (IM3Module module)
 
     const char* env  = "env";
 
-    trace = fopen ("wasm3_trace.csv","w");
-
 _   (SuppressLookupFailure (m3_LinkRawFunction (module, env, "log_execution",       "v(i)",     &m3_env_log_execution)));
 
 _   (SuppressLookupFailure (m3_LinkRawFunction (module, env, "log_exec_enter",      "v(ii)",    &m3_env_log_exec_enter)));