Use ELF function index to distinguish generated functions.

We replaced LLVMLongName and LLVMStubName with ElfFuncName,
and we are using the simple name: Art0, Art1, ..., ArtN,
as the function name of every generated functions.  This
gives us 3 benefits:

1. We can avoid the ambiguous function name returned by
   LLVMLongName() in some special situation.

2. We don't need to have the art::Method object during
   the executable linking procedure.  Besides, this will
   make bootstrapping easier.

3. Reduce the size of the ELF executable, since we don't
   have to save a long function name, which usually contains
   more than 30 characters.

Change-Id: Ib698062b272458e847ad5545d7acf33a4dc9eb85

1 files changed, 6 insertions, 0 deletions

diff --git a/src/compiler_llvm/compilation_unit.h b/src/compiler_llvm/compilation_unit.h
index eb92ce445a..1db54fc413 100644
--- a/src/compiler_llvm/compilation_unit.h
+++ b/src/compiler_llvm/compilation_unit.h
@@ -73,6 +73,11 @@ class CompilationUnit {
     return ElfImage(elf_image_);
   }
 
+  uint16_t AcquireUniqueElfFuncIndex() {
+    CHECK(num_elf_funcs_ < UINT16_MAX);
+    return num_elf_funcs_++;
+  }
+
   bool WriteBitcodeToFile();
 
   bool Materialize();
@@ -101,6 +106,7 @@ class CompilationUnit {
   std::string bitcode_filename_;
 
   size_t mem_usage_;
+  uint16_t num_elf_funcs_;
 };
 
 } // namespace compiler_llvm