[clang] 2c9dbcd - [modules] Correctly parse LateParsedTemplates in case of dependent modules.

[Vassil Vassilev via cfe-commits]

Author: Vaibhav Garg
Date: 2020-09-04T11:39:04Z
New Revision: 2c9dbcda4f71497d4a58020bb093af438fb6e967

URL: https://github.com/llvm/llvm-project/commit/2c9dbcda4f71497d4a58020bb093af438fb6e967
DIFF: https://github.com/llvm/llvm-project/commit/2c9dbcda4f71497d4a58020bb093af438fb6e967.diff

LOG: [modules] Correctly parse LateParsedTemplates in case of dependent modules.

While parsing LateParsedTemplates, Clang assumes that the Global DeclID matches
with the Local DeclID of a Decl. This is not the case when we have multiple
dependent modules , each having their own LateParsedTemplate section. In such a
case, a Local/Global DeclID confusion occurs which leads to improper casting of
FunctionDecl's.

This commit creates a Vector to map the LateParsedTemplate section of each
Module with their module file and therefore resolving the Global/Local DeclID
confusion.

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D86514

Added: 
    

Modified: 
    clang/include/clang/Serialization/ASTReader.h
    clang/lib/Serialization/ASTReader.cpp

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/Serialization/ASTReader.h b/clang/include/clang/Serialization/ASTReader.h
index b6892e295ac7..29c4f15e57b0 100644
--- a/clang/include/clang/Serialization/ASTReader.h
+++ b/clang/include/clang/Serialization/ASTReader.h
@@ -900,8 +900,9 @@ class ASTReader
   /// Delete expressions to analyze at the end of translation unit.
   SmallVector<uint64_t, 8> DelayedDeleteExprs;
 
-  // A list of late parsed template function data.
-  SmallVector<uint64_t, 1> LateParsedTemplates;
+  // A list of late parsed template function data with their module files.
+  SmallVector<std::pair<ModuleFile *, SmallVector<uint64_t, 1>>, 4>
+      LateParsedTemplates;
 
   /// The IDs of all decls to be checked for deferred diags.
   ///

diff  --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 55d68a7c6919..6f5fa67117c0 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -3722,7 +3722,9 @@ ASTReader::ReadASTBlock(ModuleFile &F, unsigned ClientLoadCapabilities) {
     }
 
     case LATE_PARSED_TEMPLATE:
-      LateParsedTemplates.append(Record.begin(), Record.end());
+      LateParsedTemplates.emplace_back(
+          std::piecewise_construct, std::forward_as_tuple(&F),
+          std::forward_as_tuple(Record.begin(), Record.end()));
       break;
 
     case OPTIMIZE_PRAGMA_OPTIONS:
@@ -8389,25 +8391,28 @@ void ASTReader::ReadPendingInstantiations(
 void ASTReader::ReadLateParsedTemplates(
     llvm::MapVector<const FunctionDecl *, std::unique_ptr<LateParsedTemplate>>
         &LPTMap) {
-  for (unsigned Idx = 0, N = LateParsedTemplates.size(); Idx < N;
-       /* In loop */) {
-    FunctionDecl *FD = cast<FunctionDecl>(GetDecl(LateParsedTemplates[Idx++]));
+  for (auto &LPT : LateParsedTemplates) {
+    ModuleFile *FMod = LPT.first;
+    RecordDataImpl &LateParsed = LPT.second;
+    for (unsigned Idx = 0, N = LateParsed.size(); Idx < N;
+         /* In loop */) {
+      FunctionDecl *FD =
+          cast<FunctionDecl>(GetLocalDecl(*FMod, LateParsed[Idx++]));
 
-    auto LT = std::make_unique<LateParsedTemplate>();
-    LT->D = GetDecl(LateParsedTemplates[Idx++]);
+      auto LT = std::make_unique<LateParsedTemplate>();
+      LT->D = GetLocalDecl(*FMod, LateParsed[Idx++]);
 
-    ModuleFile *F = getOwningModuleFile(LT->D);
-    assert(F && "No module");
+      ModuleFile *F = getOwningModuleFile(LT->D);
+      assert(F && "No module");
 
-    unsigned TokN = LateParsedTemplates[Idx++];
-    LT->Toks.reserve(TokN);
-    for (unsigned T = 0; T < TokN; ++T)
-      LT->Toks.push_back(ReadToken(*F, LateParsedTemplates, Idx));
+      unsigned TokN = LateParsed[Idx++];
+      LT->Toks.reserve(TokN);
+      for (unsigned T = 0; T < TokN; ++T)
+        LT->Toks.push_back(ReadToken(*F, LateParsed, Idx));
 
-    LPTMap.insert(std::make_pair(FD, std::move(LT)));
+      LPTMap.insert(std::make_pair(FD, std::move(LT)));
+    }
   }
-
-  LateParsedTemplates.clear();
 }
 
 void ASTReader::LoadSelector(Selector Sel) {