Bug 1569871 - MOZ_PROFILER_STARTUP set to ''/'0'/'N'/'n' does not start the profiler - r=canaltinova

(Also MOZ_BASE_PROFILER_STARTUP.)

This makes it easier to keep that variable setup in the environment, and change
its value to switch between enabling and disabling the profiler.

Differential Revision: https://phabricator.services.mozilla.com/D42447

--HG--
extra : moz-landing-system : lando

mozglue/baseprofiler/core/platform.cpp

@@ -1726,7 +1726,8 @@ static void PrintUsageThenExit(int aExitCode) {
       "  '..._VERBOSE_LOGGING' (most verbose)\n"
       "\n"
       "  MOZ_BASE_PROFILER_STARTUP\n"
-      "  If set to any value, starts the profiler immediately on start-up.\n"
+      "  If set to any value other than '' or '0'/'N'/'n', starts the\n"
+      "  profiler immediately on start-up.\n"
       "  Useful if you want profile code that runs very early.\n"
       "\n"
       "  MOZ_BASE_PROFILER_STARTUP_ENTRIES=<1..>\n"
@@ -2244,7 +2245,10 @@ void profiler_init(void* aStackTop) {
     // created on demand at the first call to PlatformStart().
 
     const char* startupEnv = getenv("MOZ_BASE_PROFILER_STARTUP");
-    if (!startupEnv || startupEnv[0] == '\0') {
+    if (!startupEnv || startupEnv[0] == '\0' ||
+        ((startupEnv[0] == '0' || startupEnv[0] == 'N' ||
+          startupEnv[0] == 'n') &&
+         startupEnv[1] == '\0')) {
       return;
     }
 

tools/profiler/core/platform.cpp

@@ -2274,7 +2274,8 @@ static void PrintUsageThenExit(int aExitCode) {
       "  'prof:3' (least verbose), 'prof:4', 'prof:5' (most verbose).\n"
       "\n"
       "  MOZ_PROFILER_STARTUP\n"
-      "  If set to any value, starts the profiler immediately on start-up.\n"
+      "  If set to any value other than '' or '0'/'N'/'n', starts the\n"
+      "  profiler immediately on start-up.\n"
       "  Useful if you want profile code that runs very early.\n"
       "\n"
       "  MOZ_PROFILER_STARTUP_ENTRIES=<1..>\n"
@@ -2907,7 +2908,10 @@ void profiler_init(void* aStackTop) {
     // created on demand at the first call to PlatformStart().
 
     const char* startupEnv = getenv("MOZ_PROFILER_STARTUP");
-    if (!startupEnv || startupEnv[0] == '\0') {
+    if (!startupEnv || startupEnv[0] == '\0' ||
+        ((startupEnv[0] == '0' || startupEnv[0] == 'N' ||
+          startupEnv[0] == 'n') &&
+         startupEnv[1] == '\0')) {
       return;
     }