Avoid use of std::string where we have const char*.

Removing the ClassHelper caused std::string creation for all calls to
Class::GetDescriptor and a significant performance regression. Make the
std::string an out argument so the caller can maintain it and its life time
while allowing GetDescriptor to return the common const char* case.

Don't generate GC maps when compilation is disabled.

Remove other uses of std::string that are occuring on critical paths.
Use the cheaper SkipClass in CompileMethod in CompilerDriver.
Specialize the utf8 as utf16 comparison code for the common shorter byte
encoding.
Force a bit of inlining, remove some UNLIKELYs (they are prone to pessimizing
code), add some LIKELYs.

x86-64 host 1-thread interpret-only of 57 apks:
Before: 29.539s
After: 23.467s

Regular compile:
Before: 1m35.347s
After: 1m20.056s

Bug: 16853450
Change-Id: Ic705ea24784bee24ab80084d06174cbf87d557ad

1 files changed, 2 insertions, 0 deletions

diff --git a/compiler/dex/verification_results.h b/compiler/dex/verification_results.h
index 7fdf767..0e7923f 100644
--- a/compiler/dex/verification_results.h
+++ b/compiler/dex/verification_results.h
@@ -56,6 +56,8 @@ class VerificationResults {
                                    const uint32_t access_flags);
 
   private:
+    const CompilerOptions* const compiler_options_;
+
     // Verified methods.
     typedef SafeMap<MethodReference, const VerifiedMethod*,
         MethodReferenceComparator> VerifiedMethodMap;