Do not cache hardcoded formats in FormatManager

The cache in FormatCache uses only a type name as key. The hardcoded
formats, synthetic children, etc inspect an entire ValueObject to
determine their eligibility, which isn't modelled in the cache. This
leads to bugs such as the one in this patch (where two similarly named
types in different files have different hardcoded summary
providers). The problem is exaggerated in the Swift language plugin
due to the language's dynamic nature.

rdar://problem/57756763

Differential Revision: https://reviews.llvm.org/D71233

Author: adrian-prantl

lldb/include/lldb/DataFormatters/FormatManager.h

@@ -209,7 +209,8 @@ class FormatManager : public IFormatChangeListener {
   ConstString m_vectortypes_category_name;
 
   template <typename ImplSP>
-  ImplSP GetCached(ValueObject &valobj, lldb::DynamicValueType use_dynamic);
+  ImplSP Get(ValueObject &valobj, lldb::DynamicValueType use_dynamic);
+  template <typename ImplSP> ImplSP GetCached(FormattersMatchData &match_data);
   template <typename ImplSP> ImplSP GetHardcoded(FormattersMatchData &);
 
   TypeCategoryMap &GetCategories() { return m_categories_map; }

lldb/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-caching/Makefile

@@ -0,0 +1,3 @@
+C_SOURCES := a.c b.c
+
+include Makefile.rules

lldb/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-caching/TestDataFormatterCaching.py

@@ -0,0 +1,27 @@
+import lldb
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test.decorators import *
+import lldbsuite.test.lldbutil as lldbutil
+
+
+class TestDataFormatterCaching(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    def setUp(self):
+        TestBase.setUp(self)
+
+    def test_with_run_command(self):
+        """
+        Test that hardcoded summary formatter matches aren't improperly cached.
+        """
+        self.build()
+        target, process, thread, bkpt = lldbutil.run_to_source_breakpoint(
+            self, 'break here', lldb.SBFileSpec('a.c'))
+        valobj = self.frame().FindVariable('f')
+        self.assertEqual(valobj.GetValue(), '4')
+        bkpt_b = target.BreakpointCreateBySourceRegex('break here',
+                                                      lldb.SBFileSpec('b.c'))
+        lldbutil.continue_to_breakpoint(process, bkpt_b)
+        valobj = self.frame().FindVariable('f4')
+        self.assertEqual(valobj.GetSummary(), '(1, 2, 3, 4)')

lldb/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-caching/a.c

@@ -0,0 +1,7 @@
+typedef float float4;
+
+int main() {
+  float4 f = 4.0f;
+  // break here
+  return a(); 
+}

lldb/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-caching/b.c

@@ -0,0 +1,8 @@
+typedef float float4 __attribute__((ext_vector_type(4)));
+void stop() {}
+int a() {
+  float4 f4 = {1, 2, 3, 4};
+  // break here
+  stop();
+  return 0;
+}

lldb/source/DataFormatters/FormatManager.cpp

@@ -622,11 +622,21 @@ ImplSP FormatManager::GetHardcoded(FormattersMatchData &match_data) {
   return retval_sp;
 }
 
-template <typename ImplSP> ImplSP
-FormatManager::GetCached(ValueObject &valobj,
-                         lldb::DynamicValueType use_dynamic) {
-  ImplSP retval_sp;
+template <typename ImplSP>
+ImplSP FormatManager::Get(ValueObject &valobj,
+                          lldb::DynamicValueType use_dynamic) {
   FormattersMatchData match_data(valobj, use_dynamic);
+  if (ImplSP retval_sp = GetCached<ImplSP>(match_data))
+    return retval_sp;
+
+  Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_DATAFORMATTERS));
+  LLDB_LOGF(log, "[%s] Search failed. Giving hardcoded a chance.", __FUNCTION__);
+  return GetHardcoded<ImplSP>(match_data);
+}
+
+template <typename ImplSP>
+ImplSP FormatManager::GetCached(FormattersMatchData &match_data) {
+  ImplSP retval_sp;
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_DATAFORMATTERS));
   if (match_data.GetTypeForCache()) {
     LLDB_LOGF(log, "\n\n[%s] Looking into cache for type %s", __FUNCTION__,
@@ -659,10 +669,6 @@ FormatManager::GetCached(ValueObject &valobj,
       return retval_sp;
     }
   }
-  if (!retval_sp) {
-    LLDB_LOGF(log, "[%s] Search failed. Giving hardcoded a chance.", __FUNCTION__);
-    retval_sp = GetHardcoded<ImplSP>(match_data);
-  }
 
   if (match_data.GetTypeForCache() && (!retval_sp || !retval_sp->NonCacheable())) {
     LLDB_LOGF(log, "[%s] Caching %p for type %s", __FUNCTION__,
@@ -678,25 +684,25 @@ FormatManager::GetCached(ValueObject &valobj,
 lldb::TypeFormatImplSP
 FormatManager::GetFormat(ValueObject &valobj,
                          lldb::DynamicValueType use_dynamic) {
-  return GetCached<lldb::TypeFormatImplSP>(valobj, use_dynamic);
+  return Get<lldb::TypeFormatImplSP>(valobj, use_dynamic);
 }
 
 lldb::TypeSummaryImplSP
 FormatManager::GetSummaryFormat(ValueObject &valobj,
                                 lldb::DynamicValueType use_dynamic) {
-  return GetCached<lldb::TypeSummaryImplSP>(valobj, use_dynamic);
+  return Get<lldb::TypeSummaryImplSP>(valobj, use_dynamic);
 }
 
 lldb::SyntheticChildrenSP
 FormatManager::GetSyntheticChildren(ValueObject &valobj,
                                     lldb::DynamicValueType use_dynamic) {
-  return GetCached<lldb::SyntheticChildrenSP>(valobj, use_dynamic);
+  return Get<lldb::SyntheticChildrenSP>(valobj, use_dynamic);
 }
 
 lldb::TypeValidatorImplSP
 FormatManager::GetValidator(ValueObject &valobj,
                             lldb::DynamicValueType use_dynamic) {
-  return GetCached<lldb::TypeValidatorImplSP>(valobj, use_dynamic);
+  return Get<lldb::TypeValidatorImplSP>(valobj, use_dynamic);
 }
 
 FormatManager::FormatManager()