Reviewers: scottb, Description: This patch adds -XcheckOverflow to the compiler, which will generate code that checks every non-long primitive arithmetic operation to see if overflow should have occurred, and throw an assertion error. This catches the case where in production mode (where everything is calculated as a double), a value that would have wrapped around now doesn't, leading to an out-of-range condition which may behave strangely. For example, hash functions frequently rely on overflow.
Please review this at http://gwt-code-reviews.appspot.com/126801 Affected files: dev/core/src/com/google/gwt/dev/Precompile.java dev/core/src/com/google/gwt/dev/jjs/JJSOptions.java dev/core/src/com/google/gwt/dev/jjs/JJSOptionsImpl.java dev/core/src/com/google/gwt/dev/jjs/JavaToJavaScriptCompiler.java dev/core/src/com/google/gwt/dev/jjs/ast/JProgram.java dev/core/src/com/google/gwt/dev/jjs/impl/OverflowDetectionNormalizer.java dev/core/src/com/google/gwt/dev/util/arg/ArgHandlerCheckOverflow.java dev/core/src/com/google/gwt/dev/util/arg/OptionCheckOverflow.java dev/core/super/com/google/gwt/dev/jjs/intrinsic/com/google/gwt/lang/Overflow.java user/src/com/google/gwt/junit/JUnitShell.java -- http://groups.google.com/group/Google-Web-Toolkit-Contributors
