[PATCH] D151529: [NFC][CLANG] Fix nullptr dereference issue in DeduceTemplateArgumentsByTypeMatch()

[Soumi Manna via Phabricator via cfe-commits]

Manna created this revision.
Manna added a reviewer: erichkeane.
Herald added a project: All.
Manna requested review of this revision.
Herald added a project: clang.

DeduceTemplateArgumentsByTypeMatch() returns null value which is dereferenced 
without checking since  
getAsIncompleteArrayType() returns nullptr and we are dereferencing null 
pointer value for S.Context->getAsIncompleteArrayType(P) when calling 
getElementType().

This patch adds an assert.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D151529

Files:
  clang/lib/Sema/SemaTemplateDeduction.cpp


Index: clang/lib/Sema/SemaTemplateDeduction.cpp
===================================================================
--- clang/lib/Sema/SemaTemplateDeduction.cpp
+++ clang/lib/Sema/SemaTemplateDeduction.cpp
@@ -1703,10 +1703,12 @@
       if (!IAA)
         return Sema::TDK_NonDeducedMismatch;
 
+      const auto *IAP = S.Context.getAsIncompleteArrayType(P);
+      assert(IAP && "Template arguments not of incomplete array type!");
+
       return DeduceTemplateArgumentsByTypeMatch(
-          S, TemplateParams,
-          S.Context.getAsIncompleteArrayType(P)->getElementType(),
-          IAA->getElementType(), Info, Deduced, TDF & TDF_IgnoreQualifiers);
+          S, TemplateParams, IAP->getElementType(), IAA->getElementType(), 
Info,
+          Deduced, TDF & TDF_IgnoreQualifiers);
     }
 
     //     T [integer-constant]



Index: clang/lib/Sema/SemaTemplateDeduction.cpp
===================================================================
--- clang/lib/Sema/SemaTemplateDeduction.cpp
+++ clang/lib/Sema/SemaTemplateDeduction.cpp
@@ -1703,10 +1703,12 @@
       if (!IAA)
         return Sema::TDK_NonDeducedMismatch;
 
+      const auto *IAP = S.Context.getAsIncompleteArrayType(P);
+      assert(IAP && "Template arguments not of incomplete array type!");
+
       return DeduceTemplateArgumentsByTypeMatch(
-          S, TemplateParams,
-          S.Context.getAsIncompleteArrayType(P)->getElementType(),
-          IAA->getElementType(), Info, Deduced, TDF & TDF_IgnoreQualifiers);
+          S, TemplateParams, IAP->getElementType(), IAA->getElementType(), Info,
+          Deduced, TDF & TDF_IgnoreQualifiers);
     }
 
     //     T [integer-constant]

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