Properly de-duplicate debug symbol names.

The simple approach was good up till now, but the interpreter
methods names are not near the compiled methods name, so use
proper full map to ensure we do not store the same name twice.

Bug: 71579677
Test: testrunner.py --host -t 137
Change-Id: I529a3b097ed20a68ad46454b47a8f8c3223f534d

1 files changed, 9 insertions, 11 deletions

diff --git a/compiler/linker/elf_builder.h b/compiler/linker/elf_builder.h
index 3145497091..1c875189c5 100644
--- a/compiler/linker/elf_builder.h
+++ b/compiler/linker/elf_builder.h
@@ -18,6 +18,7 @@
 #define ART_COMPILER_LINKER_ELF_BUILDER_H_
 
 #include <vector>
+#include <unordered_map>
 
 #include "arch/instruction_set.h"
 #include "arch/mips/instruction_set_features_mips.h"
@@ -309,27 +310,24 @@ class ElfBuilder FINAL {
                   /* info */ 0,
                   align,
                   /* entsize */ 0),
-          current_offset_(0),
-          last_offset_(0) {
+          current_offset_(0) {
     }
 
     Elf_Word Write(const std::string& name) {
       if (current_offset_ == 0) {
         DCHECK(name.empty());
-      } else if (name == last_name_) {
-        return last_offset_;  // Very simple string de-duplication.
       }
-      last_name_ = name;
-      last_offset_ = current_offset_;
-      this->WriteFully(name.c_str(), name.length() + 1);
-      current_offset_ += name.length() + 1;
-      return last_offset_;
+      auto res = written_names_.emplace(name, current_offset_);
+      if (res.second) {  // Inserted.
+        this->WriteFully(name.c_str(), name.length() + 1);
+        current_offset_ += name.length() + 1;
+      }
+      return res.first->second;  // Offset.
     }
 
    private:
     Elf_Word current_offset_;
-    std::string last_name_;
-    Elf_Word last_offset_;
+    std::unordered_map<std::string, Elf_Word> written_names_;  // Dedup strings.
   };
 
   // Writer of .dynsym and .symtab sections.