[PATCH] D17664: Move discriminator assignment to the right place.

[Dehao Chen via llvm-commits]

danielcdh created this revision.
danielcdh added reviewers: dnovillo, davidxl.
danielcdh added a subscriber: llvm-commits.

Now discriminator is assigned per-function instead of per-module.

http://reviews.llvm.org/D17664

Files:
  include/llvm/IR/DebugInfoMetadata.h
  lib/IR/DebugInfoMetadata.cpp
  lib/Transforms/Utils/AddDiscriminators.cpp

Index: lib/Transforms/Utils/AddDiscriminators.cpp
===================================================================
--- lib/Transforms/Utils/AddDiscriminators.cpp
+++ lib/Transforms/Utils/AddDiscriminators.cpp
@@ -173,8 +173,10 @@
   typedef std::pair<StringRef, unsigned> Location;
   typedef DenseMap<const BasicBlock *, Metadata *> BBScopeMap;
   typedef DenseMap<Location, BBScopeMap> LocationBBMap;
+  typedef DenseMap<Location, unsigned> LocationDiscriminatorMap;
 
   LocationBBMap LBM;
+  LocationDiscriminatorMap LDM;
 
   // Traverse all instructions in the function. If the source line location
   // of the instruction appears in other basic block, assign a new
@@ -199,8 +201,7 @@
         auto *Scope = DIL->getScope();
         auto *File =
             Builder.createFile(DIL->getFilename(), Scope->getDirectory());
-        NewScope = Builder.createLexicalBlockFile(
-            Scope, File, DIL->computeNewDiscriminator());
+        NewScope = Builder.createLexicalBlockFile(Scope, File, ++LDM[L]);
       }
       I.setDebugLoc(DILocation::get(Ctx, DIL->getLine(), DIL->getColumn(),
                                     NewScope, DIL->getInlinedAt()));
@@ -230,8 +231,10 @@
           auto *Scope = FirstDIL->getScope();
           auto *File = Builder.createFile(FirstDIL->getFilename(),
                                           Scope->getDirectory());
-          auto *NewScope = Builder.createLexicalBlockFile(
-              Scope, File, FirstDIL->computeNewDiscriminator());
+          Location L =
+              std::make_pair(FirstDIL->getFilename(), FirstDIL->getLine());
+          auto *NewScope =
+              Builder.createLexicalBlockFile(Scope, File, ++LDM[L]);
           Current->setDebugLoc(DILocation::get(
               Ctx, CurrentDIL->getLine(), CurrentDIL->getColumn(), NewScope,
               CurrentDIL->getInlinedAt()));
Index: lib/IR/DebugInfoMetadata.cpp
===================================================================
--- lib/IR/DebugInfoMetadata.cpp
+++ lib/IR/DebugInfoMetadata.cpp
@@ -66,23 +66,6 @@
                    Storage, Context.pImpl->DILocations);
 }
 
-unsigned DILocation::computeNewDiscriminator() const {
-  // FIXME: This seems completely wrong.
-  //
-  //  1. If two modules are generated in the same context, then the second
-  //     Module will get different discriminators than it would have if it were
-  //     generated in its own context.
-  //  2. If this function is called after round-tripping to bitcode instead of
-  //     before, it will give a different (and potentially incorrect!) return.
-  //
-  // The discriminator should instead be calculated from local information
-  // where it's actually needed.  This logic should be moved to
-  // AddDiscriminators::runOnFunction(), where it doesn't pollute the
-  // LLVMContext.
-  std::pair<const char *, unsigned> Key(getFilename().data(), getLine());
-  return ++getContext().pImpl->DiscriminatorTable[Key];
-}
-
 unsigned DINode::getFlag(StringRef Flag) {
   return StringSwitch<unsigned>(Flag)
 #define HANDLE_DI_FLAG(ID, NAME) .Case("DIFlag" #NAME, Flag##NAME)
Index: include/llvm/IR/DebugInfoMetadata.h
===================================================================
--- include/llvm/IR/DebugInfoMetadata.h
+++ include/llvm/IR/DebugInfoMetadata.h
@@ -1192,15 +1192,6 @@
   /// instructions that are on different basic blocks.
   inline unsigned getDiscriminator() const;
 
-  /// \brief Compute new discriminator in the given context.
-  ///
-  /// This modifies the \a LLVMContext that \c this is in to increment the next
-  /// discriminator for \c this's line/filename combination.
-  ///
-  /// FIXME: Delete this.  See comments in implementation and at the only call
-  /// site in \a AddDiscriminators::runOnFunction().
-  unsigned computeNewDiscriminator() const;
-
   Metadata *getRawScope() const { return getOperand(0); }
   Metadata *getRawInlinedAt() const {
     if (getNumOperands() == 2)


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