Data formatters: Look through array element typedefs

Summary:
Motivation: When formatting an array of typedefed chars, we would like to display the array as a string.

The string formatter currently does not trigger because the formatter lookup does not resolve typedefs for array elements (this behavior is inconsistent with pointers, for those we do look through pointee typedefs). This patch tries to make the array formatter lookup somewhat consistent with the pointer formatter lookup.

Reviewers: teemperor, clayborg

Reviewed By: teemperor, clayborg

Subscribers: clayborg, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D72133

3 files changed, 29 insertions, 6 deletions

diff --git a/lldb/source/API/SBType.cpp b/lldb/source/API/SBType.cpp
index 8efc701a79f..33b67ad4c00 100644
--- a/lldb/source/API/SBType.cpp
+++ b/lldb/source/API/SBType.cpp
@@ -212,8 +212,10 @@ SBType SBType::GetArrayElementType() {
 
   if (!IsValid())
     return LLDB_RECORD_RESULT(SBType());
-  return LLDB_RECORD_RESULT(SBType(TypeImplSP(
-      new TypeImpl(m_opaque_sp->GetCompilerType(true).GetArrayElementType()))));
+  CompilerType canonical_type =
+      m_opaque_sp->GetCompilerType(true).GetCanonicalType();
+  return LLDB_RECORD_RESULT(
+      SBType(TypeImplSP(new TypeImpl(canonical_type.GetArrayElementType()))));
 }
 
 SBType SBType::GetArrayType(uint64_t size) {
diff --git a/lldb/source/DataFormatters/FormatManager.cpp b/lldb/source/DataFormatters/FormatManager.cpp
index 08fc56a72ea..d5db3ee75bf 100644
--- a/lldb/source/DataFormatters/FormatManager.cpp
+++ b/lldb/source/DataFormatters/FormatManager.cpp
@@ -230,11 +230,33 @@ void FormatManager::GetPossibleMatches(
     if (non_ptr_type.IsTypedefType()) {
       CompilerType deffed_pointed_type =
           non_ptr_type.GetTypedefedType().GetPointerType();
+      const bool stripped_typedef = true;
       GetPossibleMatches(
           valobj, deffed_pointed_type,
           reason | lldb_private::eFormatterChoiceCriterionNavigatedTypedefs,
           use_dynamic, entries, did_strip_ptr, did_strip_ref,
-          true); // this is not exactly the usual meaning of stripping typedefs
+          stripped_typedef); // this is not exactly the usual meaning of
+                             // stripping typedefs
+    }
+  }
+
+  // For arrays with typedef-ed elements, we add a candidate with the typedef
+  // stripped.
+  uint64_t array_size;
+  if (compiler_type.IsArrayType(nullptr, &array_size, nullptr)) {
+    CompilerType element_type = compiler_type.GetArrayElementType();
+    if (element_type.IsTypedefType()) {
+      // Get the stripped element type and compute the stripped array type
+      // from it.
+      CompilerType deffed_array_type =
+          element_type.GetTypedefedType().GetArrayType(array_size);
+      const bool stripped_typedef = true;
+      GetPossibleMatches(
+          valobj, deffed_array_type,
+          reason | lldb_private::eFormatterChoiceCriterionNavigatedTypedefs,
+          use_dynamic, entries, did_strip_ptr, did_strip_ref,
+          stripped_typedef); // this is not exactly the usual meaning of
+                             // stripping typedefs
     }
   }
 
diff --git a/lldb/source/Symbol/ClangASTContext.cpp b/lldb/source/Symbol/ClangASTContext.cpp
index c846e410acf..0cc83254947 100644
--- a/lldb/source/Symbol/ClangASTContext.cpp
+++ b/lldb/source/Symbol/ClangASTContext.cpp
@@ -3924,7 +3924,7 @@ CompilerType
 ClangASTContext::GetArrayElementType(lldb::opaque_compiler_type_t type,
                                      uint64_t *stride) {
   if (type) {
-    clang::QualType qual_type(GetCanonicalQualType(type));
+    clang::QualType qual_type(GetQualType(type));
 
     const clang::Type *array_eletype =
         qual_type.getTypePtr()->getArrayElementTypeNoTypeQual();
@@ -3932,8 +3932,7 @@ ClangASTContext::GetArrayElementType(lldb::opaque_compiler_type_t type,
     if (!array_eletype)
       return CompilerType();
 
-    CompilerType element_type =
-        GetType(array_eletype->getCanonicalTypeUnqualified());
+    CompilerType element_type = GetType(clang::QualType(array_eletype, 0));
 
     // TODO: the real stride will be >= this value.. find the real one!
     if (stride)