Use trampolines for calls to helpers

This is an ARM specific optimization to the compiler
that uses trampoline islands to make calls to runtime
helper functions.  The intention is to reduce the size
of the generated code (by 2 bytes per call) without
affecting performance.

By default this is on when generating an OAT file.  It is
off when compiling to memory.

To switch this off in dex2oat, use the command line option:
--no-helper-trampolines

Enhances disassembler to print the trampoline entry on the
BL instruction like this:

0xb6a850c0: f7ffff9e  bl      -196 (0xb6a85000)  ; pTestSuspend

Bug: 12607709
Change-Id: I9202bdb7cf21252ad807bd48701f1f6ce8e3d0fe

1 files changed, 11 insertions, 3 deletions

diff --git a/compiler/driver/compiler_options.h b/compiler/driver/compiler_options.h
index 20c6bc8..52248a6 100644
--- a/compiler/driver/compiler_options.h
+++ b/compiler/driver/compiler_options.h
@@ -50,7 +50,8 @@ class CompilerOptions {
     small_method_threshold_(kDefaultSmallMethodThreshold),
     tiny_method_threshold_(kDefaultTinyMethodThreshold),
     num_dex_methods_threshold_(kDefaultNumDexMethodsThreshold),
-    generate_gdb_information_(false)
+    generate_gdb_information_(false),
+    generate_helper_trampolines_(false)
 #ifdef ART_SEA_IR_MODE
     , sea_ir_mode_(false)
 #endif
@@ -62,7 +63,8 @@ class CompilerOptions {
                   size_t small_method_threshold,
                   size_t tiny_method_threshold,
                   size_t num_dex_methods_threshold,
-                  bool generate_gdb_information
+                  bool generate_gdb_information,
+                  bool generate_helper_trampolines
 #ifdef ART_SEA_IR_MODE
                   , bool sea_ir_mode
 #endif
@@ -73,7 +75,8 @@ class CompilerOptions {
     small_method_threshold_(small_method_threshold),
     tiny_method_threshold_(tiny_method_threshold),
     num_dex_methods_threshold_(num_dex_methods_threshold),
-    generate_gdb_information_(generate_gdb_information)
+    generate_gdb_information_(generate_gdb_information),
+    generate_helper_trampolines_(generate_helper_trampolines)
 #ifdef ART_SEA_IR_MODE
     , sea_ir_mode_(sea_ir_mode)
 #endif
@@ -140,6 +143,10 @@ class CompilerOptions {
     return generate_gdb_information_;
   }
 
+  bool GenerateHelperTrampolines() const {
+    return generate_helper_trampolines_;
+  }
+
  private:
   CompilerFilter compiler_filter_;
   size_t huge_method_threshold_;
@@ -148,6 +155,7 @@ class CompilerOptions {
   size_t tiny_method_threshold_;
   size_t num_dex_methods_threshold_;
   bool generate_gdb_information_;
+  bool generate_helper_trampolines_;
 
 #ifdef ART_SEA_IR_MODE
   bool sea_ir_mode_;