Refactor code so that JIT can parse compiler options.

Currently only the CompilerOptions class. We should also
do it for the CompilerDriver options.

This will fix the flakiness seen on jdwp testing, as the
debuggable flag was not passed to the compiler.

Change-Id: I4218dd5928c9f4fe2d6191ab11e5598e7cf84bcf
diff --git a/runtime/utils.cc b/runtime/utils.cc
index dee4f9c..48dce63 100644
--- a/runtime/utils.cc
+++ b/runtime/utils.cc
@@ -1835,4 +1835,43 @@
   os << "Something went wrong, didn't find the method in the class data.";
 }
 
+static void ParseStringAfterChar(const std::string& s,
+                                 char c,
+                                 std::string* parsed_value,
+                                 UsageFn Usage) {
+  std::string::size_type colon = s.find(c);
+  if (colon == std::string::npos) {
+    Usage("Missing char %c in option %s\n", c, s.c_str());
+  }
+  // Add one to remove the char we were trimming until.
+  *parsed_value = s.substr(colon + 1);
+}
+
+void ParseDouble(const std::string& option,
+                 char after_char,
+                 double min,
+                 double max,
+                 double* parsed_value,
+                 UsageFn Usage) {
+  std::string substring;
+  ParseStringAfterChar(option, after_char, &substring, Usage);
+  bool sane_val = true;
+  double value;
+  if ((false)) {
+    // TODO: this doesn't seem to work on the emulator.  b/15114595
+    std::stringstream iss(substring);
+    iss >> value;
+    // Ensure that we have a value, there was no cruft after it and it satisfies a sensible range.
+    sane_val = iss.eof() && (value >= min) && (value <= max);
+  } else {
+    char* end = nullptr;
+    value = strtod(substring.c_str(), &end);
+    sane_val = *end == '\0' && value >= min && value <= max;
+  }
+  if (!sane_val) {
+    Usage("Invalid double value %s for option %s\n", substring.c_str(), option.c_str());
+  }
+  *parsed_value = value;
+}
+
 }  // namespace art