Debug Info: store the files and directories for each compile unit.

We now emit a line table for each compile unit. To reduce the prologue size
of each line table, the files and directories used by each compile unit are
stored in std::map<unsigned, std::vector< > > instead of std::vector< >.

The prologue for a lto'ed image can be as big as 93K. Duplicating 93K for each
compile unit causes a huge increase of debug info. With this patch, each
prologue will only emit the files required by the compile unit.

rdar://problem/13342023


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176605 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index d9f6b5e..bc3f27c 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -241,7 +241,8 @@
   if (Line == 0)
     return;
   unsigned FileID = DD->getOrCreateSourceID(V.getContext().getFilename(),
-                                            V.getContext().getDirectory());
+                                            V.getContext().getDirectory(),
+                                            getUniqueID());
   assert(FileID && "Invalid file id");
   addUInt(Die, dwarf::DW_AT_decl_file, 0, FileID);
   addUInt(Die, dwarf::DW_AT_decl_line, 0, Line);
@@ -257,7 +258,8 @@
   unsigned Line = G.getLineNumber();
   if (Line == 0)
     return;
-  unsigned FileID = DD->getOrCreateSourceID(G.getFilename(), G.getDirectory());
+  unsigned FileID = DD->getOrCreateSourceID(G.getFilename(), G.getDirectory(),
+                                            getUniqueID());
   assert(FileID && "Invalid file id");
   addUInt(Die, dwarf::DW_AT_decl_file, 0, FileID);
   addUInt(Die, dwarf::DW_AT_decl_line, 0, Line);
@@ -276,7 +278,7 @@
     return;
 
   unsigned FileID = DD->getOrCreateSourceID(SP.getFilename(),
-                                            SP.getDirectory());
+                                            SP.getDirectory(), getUniqueID());
   assert(FileID && "Invalid file id");
   addUInt(Die, dwarf::DW_AT_decl_file, 0, FileID);
   addUInt(Die, dwarf::DW_AT_decl_line, 0, Line);
@@ -293,7 +295,7 @@
   if (Line == 0)
     return;
   unsigned FileID = DD->getOrCreateSourceID(Ty.getFilename(),
-                                            Ty.getDirectory());
+                                            Ty.getDirectory(), getUniqueID());
   assert(FileID && "Invalid file id");
   addUInt(Die, dwarf::DW_AT_decl_file, 0, FileID);
   addUInt(Die, dwarf::DW_AT_decl_line, 0, Line);
@@ -311,7 +313,7 @@
     return;
   DIFile File = Ty.getFile();
   unsigned FileID = DD->getOrCreateSourceID(File.getFilename(),
-                                            File.getDirectory());
+                                            File.getDirectory(), getUniqueID());
   assert(FileID && "Invalid file id");
   addUInt(Die, dwarf::DW_AT_decl_file, 0, FileID);
   addUInt(Die, dwarf::DW_AT_decl_line, 0, Line);
@@ -329,7 +331,8 @@
     return;
   StringRef FN = NS.getFilename();
 
-  unsigned FileID = DD->getOrCreateSourceID(FN, NS.getDirectory());
+  unsigned FileID = DD->getOrCreateSourceID(FN, NS.getDirectory(),
+                                            getUniqueID());
   assert(FileID && "Invalid file id");
   addUInt(Die, dwarf::DW_AT_decl_file, 0, FileID);
   addUInt(Die, dwarf::DW_AT_decl_line, 0, Line);