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

1 files changed, 5 insertions, 2 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 7b56815040..8cb30495aa 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -305,7 +305,9 @@ class DwarfDebug {
   // A list of all the unique abbreviations in use.
   std::vector<DIEAbbrev *> Abbreviations;
 
-  // Source id map, i.e. pair of source filename and directory,
+  // Stores the current file ID for a given compile unit.
+  DenseMap <unsigned, unsigned> FileIDCUMap;
+  // Source id map, i.e. CUID, source filename and directory,
   // separated by a zero byte, mapped to a unique id.
   StringMap<unsigned, BumpPtrAllocator&> SourceIdMap;
 
@@ -626,7 +628,8 @@ public:
   /// \brief Look up the source id with the given directory and source file
   /// names. If none currently exists, create a new id and insert it in the
   /// SourceIds map.
-  unsigned getOrCreateSourceID(StringRef DirName, StringRef FullName);
+  unsigned getOrCreateSourceID(StringRef DirName, StringRef FullName,
+                               unsigned CUID);
 
   /// \brief Recursively Emits a debug information entry.
   void emitDIE(DIE *Die, std::vector<DIEAbbrev *> *Abbrevs);