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, 1 insertions, 1 deletions

diff --git a/compiler/common_compiler_test.cc b/compiler/common_compiler_test.cc
index 051cfb6dbc..18233665cd 100644
--- a/compiler/common_compiler_test.cc
+++ b/compiler/common_compiler_test.cc
@@ -314,7 +314,7 @@ void CommonCompilerTest::SetUp() {
                                               method_inliner_map_.get(),
                                               compiler_kind, instruction_set,
                                               instruction_set_features,
-                                              true, new CompilerDriver::DescriptorSet,
+                                              true, new std::set<std::string>,
                                               2, true, true, timer_.get()));
   }
   // We typically don't generate an image in unit tests, disable this optimization by default.