[libclang] Avoid crashing when getting layout info of an undeduced type.

[emilio]

Summary

When the type is not deducible, return an error instead of crashing.

This fixes https://bugs.llvm.org/show_bug.cgi?id=40813.

[Anastasia]

clang/tools/c-index-test/c-index-test.c

1695 ↗

(On Diff #188024)

Should it not return undeduced error in the other case?

[emilio]

clang/tools/c-index-test/c-index-test.c

1695 ↗

(On Diff #188024)

I'm not sure what you mean, can you clarify?

The undeduced error is only returned when you try to access the Auto type which is the return value, not the function type, which has a known layout.

So in the error case, T here is the auto Tie(void*) const; type, and RT is the undeduced auto type, which is what crashed.

We had no way to exercise this in c-index-test, so I changed it to exercise this codepath too. I can add a CHECK for the error code if you want.

[Anastasia]

clang/tools/c-index-test/c-index-test.c

1695 ↗

(On Diff #188024)

Yep, error check would be good since it's covers better changes in your patch.

[emilio]

Add CHECK tests.

[emilio]

Huh, somehow forgot to press "Submit" this morning :)

clang/tools/c-index-test/c-index-test.c

1695 ↗

(On Diff #188024)

Alrighty, done!

[Anastasia]

LGTM! Thanks!

[emilio]

Thank you for all the reviews! :)

include/clang-c/Index.h

  * The version constants for the libclang API.
  * CINDEX_VERSION_MINOR should increase when there are API additions.
  * CINDEX_VERSION_MAJOR is intended for "major" source/ABI breaking changes.
  *
  * The policy about the libclang API was always to keep it source and ABI
  * compatible, thus CINDEX_VERSION_MAJOR is expected to remain stable.
  */
 #define CINDEX_VERSION_MAJOR 0
-#define CINDEX_VERSION_MINOR 52
+#define CINDEX_VERSION_MINOR 53
 
 #define CINDEX_VERSION_ENCODE(major, minor) ( \
       ((major) * 10000)                       \
     + ((minor) *     1))
 
 #define CINDEX_VERSION CINDEX_VERSION_ENCODE( \
     CINDEX_VERSION_MAJOR,                     \
     CINDEX_VERSION_MINOR )
enum CXTypeLayoutError {
   CXTypeLayoutError_Dependent = -3,
   /**
    * The type is not a constant size type.
    */
   CXTypeLayoutError_NotConstantSize = -4,
   /**
    * The Field name is not valid for this record.
    */
-  CXTypeLayoutError_InvalidFieldName = -5
+  CXTypeLayoutError_InvalidFieldName = -5,
+  /**
+   * The type is undeduced.
+   */
+  CXTypeLayoutError_Undeduced = -6
 };
 
 /**
  * Return the alignment of a type in bytes as per C++[expr.alignof]
  *   standard.
  *
  * If the type declaration is invalid, CXTypeLayoutError_Invalid is returned.
  * If the type declaration is an incomplete type, CXTypeLayoutError_Incomplete

test/Index/print-type-size.cpp

 
 plopplop;
 
 // CHECK64: StructDecl=lastValid:[[@LINE+2]]:8 (Definition) [type=CrashTest::lastValid] [typekind=Record] [sizeof=1] [alignof=1]
 // CHECK32: StructDecl=lastValid:[[@LINE+1]]:8 (Definition) [type=CrashTest::lastValid] [typekind=Record] [sizeof=1] [alignof=1]
 struct lastValid {
 };
 
+// CHECK64: CXXMethod=Tie:[[@LINE+3]]:8 (const) [type=auto (void *) const] [typekind=FunctionProto] [sizeof=1] [alignof=4] [resulttype=auto] [resulttypekind=Auto] [resultsizeof=-6] [resultalignof=-6]
+// CHECK32: CXXMethod=Tie:[[@LINE+2]]:8 (const) [type=auto (void *) const] [typekind=FunctionProto] [sizeof=1] [alignof=4] [resulttype=auto] [resulttypekind=Auto] [resultsizeof=-6] [resultalignof=-6]
+class BrowsingContext {
+  auto Tie(void*) const;
+};
+
 }

tools/c-index-test/c-index-test.c

/* Print if it is an anonymous record or namespace. */
       }
     }
 
     printf("\n");
   }
   return CXChildVisit_Recurse;
 }
 
-static enum CXChildVisitResult PrintTypeSize(CXCursor cursor, CXCursor p,
-                                             CXClientData d) {
-  CXType T;
-  enum CXCursorKind K = clang_getCursorKind(cursor);
-  if (clang_isInvalid(K))
-    return CXChildVisit_Recurse;
-  T = clang_getCursorType(cursor);
-  PrintCursor(cursor, NULL);
-  PrintTypeAndTypeKind(T, " [type=%s] [typekind=%s]");
+static void PrintSingleTypeSize(CXType T, const char *TypeKindFormat,
+                                const char *SizeFormat,
+                                const char *AlignFormat) {
+  PrintTypeAndTypeKind(T, TypeKindFormat);
   /* Print the type sizeof if applicable. */
   {
     long long Size = clang_Type_getSizeOf(T);
     if (Size >= 0 || Size < -1 ) {
-      printf(" [sizeof=%lld]", Size);
+      printf(SizeFormat, Size);
     }
   }
   /* Print the type alignof if applicable. */
   {
     long long Align = clang_Type_getAlignOf(T);
     if (Align >= 0 || Align < -1) {
-      printf(" [alignof=%lld]", Align);
-    }
+      printf(AlignFormat, Align);
+    }
+
+  /* Print the return type if it exists. */
+  {
+    CXType RT = clang_getResultType(T);
+    if (RT.kind != CXType_Invalid)
+      PrintSingleTypeSize(RT, " [resulttype=%s] [resulttypekind=%s]",
+                              " [resultsizeof=%lld]", " [resultalignof=%lld]");
   }
+}
+
+static enum CXChildVisitResult PrintTypeSize(CXCursor cursor, CXCursor p,
+                                             CXClientData d) {
+  CXType T;
+  enum CXCursorKind K = clang_getCursorKind(cursor);
+  if (clang_isInvalid(K))
+    return CXChildVisit_Recurse;
+  T = clang_getCursorType(cursor);
+  PrintCursor(cursor, NULL);
+  PrintSingleTypeSize(T, " [type=%s] [typekind=%s]", " [sizeof=%lld]",
+                      " [alignof=%lld]");
   /* Print the record field offset if applicable. */
   {
     CXString FieldSpelling = clang_getCursorSpelling(cursor);
     const char *FieldName = clang_getCString(FieldSpelling);
     /* recurse to get the first parent record that is not anonymous. */
     unsigned RecordIsAnonymous = 0;
     if (clang_getCursorKind(cursor) == CXCursor_FieldDecl) {
       CXCursor Record;
/* Print the record field offset if applicable. */
     clang_disposeString(FieldSpelling);
   }
   /* Print if its a bitfield */
   {
     int IsBitfield = clang_Cursor_isBitField(cursor);
     if (IsBitfield)
       printf(" [BitFieldSize=%d]", clang_getFieldDeclBitWidth(cursor));
   }
+
   printf("\n");
+
   return CXChildVisit_Recurse;
 }
 
 /******************************************************************************/
 /* Mangling testing.                                                          */
 /******************************************************************************/
 
 static enum CXChildVisitResult PrintMangledName(CXCursor cursor, CXCursor p,

tools/libclang/CXType.cpp

long long clang_Type_getAlignOf(CXType T) {
   //                    or array.
   // [expr.alignof] p3: if reference type, return size of referenced type
   if (QT->isReferenceType())
     QT = QT.getNonReferenceType();
   if (QT->isIncompleteType())
     return CXTypeLayoutError_Incomplete;
   if (QT->isDependentType())
     return CXTypeLayoutError_Dependent;
+  if (const auto *Deduced = dyn_cast<DeducedType>(QT))
+    if (Deduced->getDeducedType().isNull())
+      return CXTypeLayoutError_Undeduced;
   // Exceptions by GCC extension - see ASTContext.cpp:1313 getTypeInfoImpl
   // if (QT->isFunctionType()) return 4; // Bug #15511 - should be 1
   // if (QT->isVoidType()) return 1;
   return Ctx.getTypeAlignInChars(QT).getQuantity();
 }
 
 CXType clang_Type_getClassType(CXType CT) {
   QualType ET = QualType();
long long clang_Type_getSizeOf(CXType T) {
   // [expr.sizeof] p3: pointer ok, function not ok.
   // [gcc extension] lib/AST/ExprConstant.cpp:1372 HandleSizeof : vla == error
   if (QT->isIncompleteType())
     return CXTypeLayoutError_Incomplete;
   if (QT->isDependentType())
     return CXTypeLayoutError_Dependent;
   if (!QT->isConstantSizeType())
     return CXTypeLayoutError_NotConstantSize;
+  if (const auto *Deduced = dyn_cast<DeducedType>(QT))
+    if (Deduced->getDeducedType().isNull())
+      return CXTypeLayoutError_Undeduced;
   // [gcc extension] lib/AST/ExprConstant.cpp:1372
   //                 HandleSizeof : {voidtype,functype} == 1
   // not handled by ASTContext.cpp:1313 getTypeInfoImpl
   if (QT->isVoidType() || QT->isFunctionType())
     return 1;
   return Ctx.getTypeSizeInChars(QT).getQuantity();
 }