From 0f962a8e61e1c094a89df17f9d3ad947d31c4e5c Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Wed, 10 Feb 2010 17:16:49 +0000
Subject: [PATCH] Teach AST merging that variables with incomplete array types
 can be merged with variables of constant array types. Also, make sure that we
 call DiagnosticClient's BeginSourceFile/EndSourceFile, so that it has a
 LangOptions to work with.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@95782 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/AST/ASTImporter.cpp     | 27 +++++++++++++++++++++++++++
 lib/Frontend/ASTMerge.cpp   |  6 ++++--
 test/ASTMerge/Inputs/var1.c |  4 ++++
 test/ASTMerge/Inputs/var2.c |  4 ++++
 test/ASTMerge/var.c         |  2 ++
 5 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/lib/AST/ASTImporter.cpp b/lib/AST/ASTImporter.cpp
index 75917cf04c..9fb695e4e1 100644
--- a/lib/AST/ASTImporter.cpp
+++ b/lib/AST/ASTImporter.cpp
@@ -500,6 +500,33 @@ Decl *ASTNodeImporter::VisitVarDecl(VarDecl *D) {
             break;
           }
 
+          if (const IncompleteArrayType *FoundArray
+                = Importer.getToContext().getAsIncompleteArrayType(
+                                                        FoundVar->getType())) {
+            if (const ConstantArrayType *TArray
+                  = Importer.getToContext().getAsConstantArrayType(T)) {
+              if (Importer.getToContext().typesAreCompatible(
+                                               TArray->getElementType(), 
+                                               FoundArray->getElementType())) {
+                FoundVar->setType(T);
+                MergeWithVar = FoundVar;
+                break;
+              }
+            }
+          } else if (const IncompleteArrayType *TArray
+                        = Importer.getToContext().getAsIncompleteArrayType(T)) {
+            if (const ConstantArrayType *FoundArray
+                   = Importer.getToContext().getAsConstantArrayType(
+                                                         FoundVar->getType())) {
+              if (Importer.getToContext().typesAreCompatible(
+                                               TArray->getElementType(), 
+                                               FoundArray->getElementType())) {
+                MergeWithVar = FoundVar;
+                break;
+              }
+            }
+          }
+
           Importer.ToDiag(Loc, diag::err_odr_variable_type_inconsistent)
             << Name << T << FoundVar->getType();
           Importer.ToDiag(FoundVar->getLocation(), diag::note_odr_value_here)
diff --git a/lib/Frontend/ASTMerge.cpp b/lib/Frontend/ASTMerge.cpp
index d51647bb16..f2de09a74c 100644
--- a/lib/Frontend/ASTMerge.cpp
+++ b/lib/Frontend/ASTMerge.cpp
@@ -32,6 +32,8 @@ bool ASTMergeAction::BeginSourceFileAction(CompilerInstance &CI,
 
 void ASTMergeAction::ExecuteAction() {
   CompilerInstance &CI = getCompilerInstance();
+  CI.getDiagnostics().getClient()->BeginSourceFile(
+                                         CI.getASTContext().getLangOptions());
   CI.getDiagnostics().SetArgToStringFn(&FormatASTNodeDiagnosticArgument,
                                        &CI.getASTContext());
   for (unsigned I = 0, N = ASTFiles.size(); I != N; ++I) {
@@ -68,8 +70,8 @@ void ASTMergeAction::ExecuteAction() {
     delete Unit;
   }
 
-
-  return AdaptedAction->ExecuteAction();
+  AdaptedAction->ExecuteAction();
+  CI.getDiagnostics().getClient()->EndSourceFile();
 }
 
 void ASTMergeAction::EndSourceFileAction() {
diff --git a/test/ASTMerge/Inputs/var1.c b/test/ASTMerge/Inputs/var1.c
index 465258988b..4f5cbe16ab 100644
--- a/test/ASTMerge/Inputs/var1.c
+++ b/test/ASTMerge/Inputs/var1.c
@@ -1,3 +1,7 @@
 int *x0;
 float **x1;
 #include "var1.h"
+int xarray0[17];
+int xarray1[];
+int xarray2[18];
+int xarray3[18];
diff --git a/test/ASTMerge/Inputs/var2.c b/test/ASTMerge/Inputs/var2.c
index e93a010cbf..01986e4208 100644
--- a/test/ASTMerge/Inputs/var2.c
+++ b/test/ASTMerge/Inputs/var2.c
@@ -1,3 +1,7 @@
 int *x0;
 double *x1;
 int x2;
+int xarray0[17];
+int xarray1[17];
+int xarray2[];
+int xarray3[17];
diff --git a/test/ASTMerge/var.c b/test/ASTMerge/var.c
index 98ad7ab4a0..06bebd5ee8 100644
--- a/test/ASTMerge/var.c
+++ b/test/ASTMerge/var.c
@@ -7,3 +7,5 @@
 // CHECK: var2.c:3:5: error: external variable 'x2' declared with incompatible types in different translation units ('int' vs. 'double')
 // CHECK: In file included from{{.*}}var1.c:3:
 // CHECK: var1.h:1:8: note: declared here with type 'double'
+// CHECK: error: external variable 'xarray3' declared with incompatible types in different translation units ('int [17]' vs. 'int [18]')
+// CHECK: var1.c:7:5: note: declared here with type 'int [18]'
-- 
2.50.1