From 2255ce4165f936f695111020fa664b259a875c4a Mon Sep 17 00:00:00 2001
From: Andrew Katson <katsonandrew3.5@gmail.com>
Date: Fri, 5 Nov 2021 09:45:00 -0700
Subject: [PATCH] Ignore --starlark_cpu_profile on Windows.

Closes #14196.

PiperOrigin-RevId: 407843471
---
 .../build/lib/runtime/BlazeCommandDispatcher.java        | 5 +++--
 src/main/java/net/starlark/java/eval/BUILD               | 1 +
 src/main/java/net/starlark/java/eval/CpuProfiler.java    | 9 +++++++--
 src/main/java/net/starlark/java/eval/Starlark.java       | 4 ++--
 .../java/net/starlark/java/eval/CpuProfilerTest.java     | 7 ++++++-
 5 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/src/main/java/com/google/devtools/build/lib/runtime/BlazeCommandDispatcher.java b/src/main/java/com/google/devtools/build/lib/runtime/BlazeCommandDispatcher.java
index 529bc8fc8dee75..e7a0ce81a1fb4d 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/BlazeCommandDispatcher.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/BlazeCommandDispatcher.java
@@ -351,6 +351,7 @@ private BlazeCommandResult execExclusively(
     storedEventHandler.post(profilerStartedEvent);
 
     // Enable Starlark CPU profiling (--starlark_cpu_profile=/tmp/foo.pprof.gz)
+    boolean success = false;
     if (!commonOptions.starlarkCpuProfile.isEmpty()) {
       FileOutputStream out;
       try {
@@ -362,7 +363,7 @@ private BlazeCommandResult execExclusively(
             message, FailureDetails.Command.Code.STARLARK_CPU_PROFILE_FILE_INITIALIZATION_FAILURE);
       }
       try {
-        Starlark.startCpuProfile(out, Duration.ofMillis(10));
+        success = Starlark.startCpuProfile(out, Duration.ofMillis(10));
       } catch (IllegalStateException ex) { // e.g. SIGPROF in use
         String message = Strings.nullToEmpty(ex.getMessage());
         outErr.printErrLn(message);
@@ -591,7 +592,7 @@ private BlazeCommandResult execExclusively(
       }
 
       // Finalize the Starlark CPU profile.
-      if (!commonOptions.starlarkCpuProfile.isEmpty()) {
+      if (!commonOptions.starlarkCpuProfile.isEmpty() && success) {
         try {
           Starlark.stopCpuProfile();
         } catch (IOException ex) {
diff --git a/src/main/java/net/starlark/java/eval/BUILD b/src/main/java/net/starlark/java/eval/BUILD
index 3ee51dfa23a20d..c3b5897ae4b813 100644
--- a/src/main/java/net/starlark/java/eval/BUILD
+++ b/src/main/java/net/starlark/java/eval/BUILD
@@ -57,6 +57,7 @@ java_library(
         "//src/main/java/net/starlark/java/spelling",
         "//src/main/java/net/starlark/java/syntax",
         "//third_party:error_prone_annotations",
+        "//third_party:flogger",
         "//third_party:guava",
         "//third_party:jsr305",
     ],
diff --git a/src/main/java/net/starlark/java/eval/CpuProfiler.java b/src/main/java/net/starlark/java/eval/CpuProfiler.java
index 85f0b24b29e60c..fd2e8bbd1df51e 100644
--- a/src/main/java/net/starlark/java/eval/CpuProfiler.java
+++ b/src/main/java/net/starlark/java/eval/CpuProfiler.java
@@ -17,6 +17,7 @@
 import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.google.common.collect.ImmutableList;
+import com.google.common.flogger.GoogleLogger;
 import java.io.ByteArrayOutputStream;
 import java.io.FileDescriptor;
 import java.io.FileInputStream;
@@ -93,6 +94,8 @@ final class CpuProfiler {
     JNI.load();
   }
 
+  private static final GoogleLogger logger = GoogleLogger.forEnclosingClass();
+
   private final PprofWriter pprof;
 
   private CpuProfiler(OutputStream out, Duration period) {
@@ -126,9 +129,10 @@ static StarlarkThread setStarlarkThread(StarlarkThread thread) {
   }
 
   /** Start the profiler. */
-  static void start(OutputStream out, Duration period) {
+  static boolean start(OutputStream out, Duration period) {
     if (!supported()) {
-      throw new UnsupportedOperationException("this platform does not support Starlark profiling");
+      logger.atWarning().log("--starlark_cpu_profile is unsupported on this platform");
+      return false;
     }
     if (instance != null) {
       throw new IllegalStateException("profiler started twice without intervening stop");
@@ -140,6 +144,7 @@ static void start(OutputStream out, Duration period) {
     }
 
     instance = new CpuProfiler(out, period);
+    return true;
   }
 
   /** Stop the profiler and wait for the log to be written. */
diff --git a/src/main/java/net/starlark/java/eval/Starlark.java b/src/main/java/net/starlark/java/eval/Starlark.java
index d84e17c0a9ee3f..c014a11ece578c 100644
--- a/src/main/java/net/starlark/java/eval/Starlark.java
+++ b/src/main/java/net/starlark/java/eval/Starlark.java
@@ -959,8 +959,8 @@ private static StarlarkFunction newExprFunction(
    * @throws IllegalStateException exception if the Starlark profiler is already running or if the
    *     operating system's profiling resources for this process are already in use.
    */
-  public static void startCpuProfile(OutputStream out, Duration period) {
-    CpuProfiler.start(out, period);
+  public static boolean startCpuProfile(OutputStream out, Duration period) {
+    return CpuProfiler.start(out, period);
   }
 
   /**
diff --git a/src/test/java/net/starlark/java/eval/CpuProfilerTest.java b/src/test/java/net/starlark/java/eval/CpuProfilerTest.java
index 5ce9d9adbcf4b9..d36e537bba4cf0 100644
--- a/src/test/java/net/starlark/java/eval/CpuProfilerTest.java
+++ b/src/test/java/net/starlark/java/eval/CpuProfilerTest.java
@@ -45,7 +45,12 @@ public static void main(String[] args) throws Exception {
     // Start writing profile to temporary file.
     File profile = java.io.File.createTempFile("pprof", ".gz", null);
     OutputStream prof = new FileOutputStream(profile);
-    Starlark.startCpuProfile(prof, Duration.ofMillis(10));
+    boolean success = Starlark.startCpuProfile(prof, Duration.ofMillis(10));
+
+    if (!success) {
+      System.err.println("Failed to start cpu profiler");
+      System.exit(1);
+    }
 
     // This program consumes about 3s of CPU.
     ParserInput input =