8318671: Potential uninitialized uintx value after JDK-8317683

Reviewed-by: thartmann, shade

src/hotspot/share/compiler/compilerOracle.cpp

@@ -673,20 +673,27 @@ static bool parseMemLimit(const char* line, intx& value, int& bytes_read, char*
   return true;
 }
 
-static bool parseEnumValueAsUintx(enum CompileCommand option, const char* line, uintx& value, int& bytes_read, char* errorbuf, const int buf_size) {
-  if (option == CompileCommand::MemStat) {
-    if (strncasecmp(line, "collect", 7) == 0) {
-      value = (uintx)MemStatAction::collect;
-    } else if (strncasecmp(line, "print", 5) == 0) {
-      value = (uintx)MemStatAction::print;
-      print_final_memstat_report = true;
-    } else {
-      jio_snprintf(errorbuf, buf_size, "MemStat: invalid value expected 'collect' or 'print' (omitting value means 'collect')");
-    }
-    return true; // handled
+static bool parseMemStat(const char* line, uintx& value, int& bytes_read, char* errorbuf, const int buf_size) {
+
+#define IF_ENUM_STRING(S, CMD)                \
+  if (strncasecmp(line, S, strlen(S)) == 0) { \
+    bytes_read += (int)strlen(S);             \
+    CMD                                       \
+    return true;                              \
   }
+
+  IF_ENUM_STRING("collect", {
+    value = (uintx)MemStatAction::collect;
+  });
+  IF_ENUM_STRING("print", {
+    value = (uintx)MemStatAction::print;
+    print_final_memstat_report = true;
+  });
+#undef IF_ENUM_STRING
+
+  jio_snprintf(errorbuf, buf_size, "MemStat: invalid option");
+
   return false;
-#undef HANDLE_VALUE
 }
 
 static void scan_value(enum OptionType type, char* line, int& total_bytes_read,
@@ -714,11 +721,13 @@ static void scan_value(enum OptionType type, char* line, int& total_bytes_read,
     }
   } else if (type == OptionType::Uintx) {
     uintx value;
-    // Is it a named enum?
-    bool success = parseEnumValueAsUintx(option, line, value, bytes_read, errorbuf, buf_size);
-    if (!success) {
-      // Is it a raw number?
-      success = (sscanf(line, "" UINTX_FORMAT "%n", &value, &bytes_read) == 1);
+    bool success = false;
+    if (option == CompileCommand::MemStat) {
+      // Special parsing for MemStat
+      success = parseMemStat(line, value, bytes_read, errorbuf, buf_size);
+    } else {
+      // parse as raw number
+      success = sscanf(line, "" UINTX_FORMAT "%n", &value, &bytes_read) == 1;
     }
     if (success) {
       total_bytes_read += bytes_read;

test/hotspot/jtreg/compiler/compilercontrol/commands/MemStatTest.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8318671
+ * @summary Tests various ways to call memstat
+ * @library /test/lib /
+ *
+ * @run driver compiler.compilercontrol.commands.MemStatTest
+ */
+
+package compiler.compilercontrol.commands;
+
+import jdk.test.lib.process.ProcessTools;
+
+public class MemStatTest {
+    public static void main(String[] args) throws Exception {
+        // default => collect
+        ProcessTools.executeTestJvm("-XX:CompileCommand=MemStat,*.*", "-version")
+                .shouldHaveExitValue(0)
+                .shouldNotContain("CompileCommand: An error occurred during parsing")
+                .shouldContain("CompileCommand: MemStat *.* uintx MemStat = 1"); // should be registered
+        // collect explicit
+        ProcessTools.executeTestJvm("-XX:CompileCommand=MemStat,*.*,collect", "-version")
+                .shouldHaveExitValue(0)
+                .shouldNotContain("CompileCommand: An error occurred during parsing")
+                .shouldContain("CompileCommand: MemStat *.* uintx MemStat = 1"); // should be registered
+        // print explicit
+        ProcessTools.executeTestJvm("-XX:CompileCommand=MemStat,*.*,print", "-version")
+                .shouldHaveExitValue(0)
+                .shouldNotContain("CompileCommand: An error occurred during parsing")
+                .shouldContain("CompileCommand: MemStat *.* uintx MemStat = 2");
+        // invalid suboption
+        ProcessTools.executeTestJvm("-XX:CompileCommand=MemStat,*.*,invalid", "-version")
+                .shouldNotHaveExitValue(0)
+                .shouldContain("CompileCommand: An error occurred during parsing")
+                .shouldContain("Error: Value cannot be read for option 'MemStat'")
+                .shouldNotContain("CompileCommand: MemStat"); // should *NOT* be registered
+    }
+}

test/hotspot/jtreg/serviceability/dcmd/compiler/CompilerMemoryStatisticTest.java

@@ -39,18 +39,6 @@
  * @run main/othervm -XX:CompileCommand=memstat,*.* CompilerMemoryStatisticTest
  */
 
-/*
- * @test CompilerMemoryStatisticTest
- * @summary Test Compiler.memory
- * @requires vm.compiler1.enabled
- * @requires vm.compiler2.enabled
- *
- * @library /test/lib
- * @modules java.base/jdk.internal.misc
- *          java.management
- * @run main/othervm -XX:CompileCommand=memstat,*.*,collect CompilerMemoryStatisticTest
- */
-
 public class CompilerMemoryStatisticTest {
 
     public static void main(String args[]) throws Exception {