[ASTImporter] Lookup SearchName instead of Name

[szepet]

Summary

When the SearchName is already calculated we should use that for the lookup.
That is why the check for a found TypedefNameDecl can be relevant in the for loop and we (probably) have to iterate over fewer decls.
I havent added test cases because it does not produce a bug since in the isStrucuralMatch function calls to the StructuralEquivalenceContext::Finish() function and in case of unnamed decls it checks for TypeDefName and returns false (without any warning message).

[a.sidorin]

Looks good. Thank you!
Could you try to write a test using the fact that new code covers typedefs for anonymous structures?

[szepet]

Test case added.

[a.sidorin]

LGTM, thank you!

lib/AST/ASTImporter.cpp

if (!SearchName && D->getTypedefNameForAnonDecl()) {
     IDNS = Decl::IDNS_Ordinary;
   } else if (Importer.getToContext().getLangOpts().CPlusPlus)
     IDNS |= Decl::IDNS_Ordinary;
   
   // We may already have an enum of the same name; try to find and match it.
   if (!DC->isFunctionOrMethod() && SearchName) {
     SmallVector<NamedDecl *, 4> ConflictingDecls;
     SmallVector<NamedDecl *, 2> FoundDecls;
-    DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
+    DC->getRedeclContext()->localUncachedLookup(SearchName, FoundDecls);
     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
         continue;
       
       Decl *Found = FoundDecls[I];
       if (TypedefNameDecl *Typedef = dyn_cast<TypedefNameDecl>(Found)) {
         if (const TagType *Tag = Typedef->getUnderlyingType()->getAs<TagType>())
           Found = Tag->getDecl();
Decl *ASTNodeImporter::VisitRecordDecl(RecordDecl *D) {
   } else if (Importer.getToContext().getLangOpts().CPlusPlus)
     IDNS |= Decl::IDNS_Ordinary;
 
   // We may already have a record of the same name; try to find and match it.
   RecordDecl *AdoptDecl = nullptr;
   if (!DC->isFunctionOrMethod()) {
     SmallVector<NamedDecl *, 4> ConflictingDecls;
     SmallVector<NamedDecl *, 2> FoundDecls;
-    DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
+    DC->getRedeclContext()->localUncachedLookup(SearchName, FoundDecls);
     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
         continue;
       
       Decl *Found = FoundDecls[I];
       if (TypedefNameDecl *Typedef = dyn_cast<TypedefNameDecl>(Found)) {
         if (const TagType *Tag = Typedef->getUnderlyingType()->getAs<TagType>())
           Found = Tag->getDecl();

test/ASTMerge/struct/Inputs/struct1.c

struct DeepError {
   struct DeeperError { int i; int f; } *Deeper;
 } xDeep;
 
 // Matches
 struct {
   Int i;
   float f;
 } x11;
+
+// Matches
+typedef struct {
+  Int i;
+  float f;
+} S12;
+
+S12 x12;
+
+// Mismatch
+typedef struct {
+  Float i; // Mismatch here.
+  float f;
+} S13;
+
+S13 x13;

test/ASTMerge/struct/Inputs/struct2.c

struct DeepError {
   struct DeeperError { int i; float f; } *Deeper;
 } xDeep;
 
 // Matches
 struct {
   int i;
   float f;
 } x11;
+
+// Matches
+typedef struct {
+  int i;
+  float f;
+} S12;
+
+S12 x12;
+
+// Mismatch
+typedef struct {
+  int i; // Mismatch here.
+  float f;
+} S13;
+
+S13 x13;

test/ASTMerge/struct/test.c

 // CHECK: struct1.c:56:10: warning: type 'struct DeeperError' has incompatible definitions in different translation units
 // CHECK: struct1.c:56:35: note: field 'f' has type 'int' here
 // CHECK: struct2.c:53:37: note: field 'f' has type 'float' here
 // CHECK: struct1.c:54:8: warning: type 'struct DeepError' has incompatible definitions in different translation units
 // CHECK: struct1.c:56:41: note: field 'Deeper' has type 'struct DeeperError *' here
 // CHECK: struct2.c:53:43: note: field 'Deeper' has type 'struct DeeperError *' here
 // CHECK: struct2.c:54:3: error: external variable 'xDeep' declared with incompatible types in different translation units ('struct DeepError' vs. 'struct DeepError')
 // CHECK: struct1.c:57:3: note: declared here with type 'struct DeepError'
-// CHECK: 8 warnings and 7 errors generated
+// CHECK: struct1.c:74:9: warning: type 'S13' has incompatible definitions in different translation units
+// CHECK: struct1.c:75:9: note: field 'i' has type 'Float' (aka 'float') here
+// CHECK: struct2.c:72:7: note: field 'i' has type 'int' here
+// CHECK: struct2.c:76:5: error: external variable 'x13' declared with incompatible types in different translation units ('S13' vs. 'S13')
+// CHECK: struct1.c:79:5: note: declared here with type 'S13'
+// CHECK: 9 warnings and 8 errors generated