allow users to enable GDB JIT integration on release builds

Author: vchuravy

doc/src/manual/environment-variables.md

@@ -314,6 +314,12 @@ event listener for just-in-time (JIT) profiling.
     * [OProfile](http://oprofile.sourceforge.net/news/) (`USE_OPROFILE_JITEVENTS` set to `1`
       in the build configuration).
 
+### `ENABLE_GDBLISTENER`
+
+If set to anything besides `0` enables GDB registration of Julia code on release builds.
+On debug builds of Julia this is always enabled. Recommended to use with `-g 2`.
+
+
 ### `JULIA_LLVM_ARGS`
 
 Arguments to be passed to the LLVM backend.

src/codegen.cpp

@@ -7728,10 +7728,9 @@ extern "C" void jl_init_llvm(void)
     std::string DL = jl_data_layout.getStringRepresentation() + "-ni:10:11:12:13";
     jl_data_layout.reset(DL);
 
-// Register GDB event listener
-#ifdef JL_DEBUG_BUILD
-    jl_ExecutionEngine->RegisterJITEventListener(JITEventListener::createGDBRegistrationListener());
-#endif
+    // Register GDB event listener
+    if(jl_using_gdb_jitevents)
+        jl_ExecutionEngine->RegisterJITEventListener(JITEventListener::createGDBRegistrationListener());
 
 #ifdef JL_USE_INTEL_JITEVENTS
     if (jl_using_intel_jitevents)

src/init.c

@@ -436,6 +436,8 @@ char jl_using_oprofile_jitevents = 0; // Non-zero if running under OProfile
 char jl_using_perf_jitevents = 0;
 #endif
 
+char jl_using_gdb_jitevents = 0;
+
 int isabspath(const char *in) JL_NOTSAFEPOINT
 {
 #ifdef _OS_WINDOWS_
@@ -692,6 +694,15 @@ void _julia_init(JL_IMAGE_SEARCH rel)
     }
 #endif
 
+#if defined(JL_DEBUG_BUILD)
+    jl_using_gdb_jitevents = 1;
+# else
+    const char *jit_gdb = getenv("ENABLE_GDBLISTENER");
+    if (jit_gdb && atoi(jit_gdb)) {
+        jl_using_gdb_jitevents = 1;
+    }
+#endif
+
     if ((jl_options.outputo || jl_options.outputbc || jl_options.outputasm) &&
         (jl_options.code_coverage || jl_options.malloc_log)) {
         jl_error("cannot generate code-coverage or track allocation information while generating a .o, .bc, or .s output file");

src/julia_internal.h

@@ -595,6 +595,7 @@ extern char jl_using_oprofile_jitevents;
 #ifdef JL_USE_PERF_JITEVENTS
 extern char jl_using_perf_jitevents;
 #endif
+extern char jl_using_gdb_jitevents;
 extern size_t jl_arr_xtralloc_limit;
 
 // -- init.c -- //