[PATCH] D152140: [Clang] Limit FunctionTypeExtraBitfields::NumExceptionType to 16 bits.

[Sander de Smalen via Phabricator via cfe-commits]

sdesmalen updated this revision to Diff 528431.
sdesmalen added a comment.

Use uint16_t instead of unsigned bitfield.
Also removed accessor methods in favour of assert at point of writing 
NumExceptionType.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D152140/new/

https://reviews.llvm.org/D152140

Files:
  clang/include/clang/AST/Type.h
  clang/lib/AST/Type.cpp


Index: clang/lib/AST/Type.cpp
===================================================================
--- clang/lib/AST/Type.cpp
+++ clang/lib/AST/Type.cpp
@@ -3371,7 +3371,10 @@
   // Fill in the exception type array if present.
   if (getExceptionSpecType() == EST_Dynamic) {
     auto &ExtraBits = *getTrailingObjects<FunctionTypeExtraBitfields>();
-    ExtraBits.NumExceptionType = epi.ExceptionSpec.Exceptions.size();
+    auto NumExceptions = epi.ExceptionSpec.Exceptions.size();
+    assert(NumExceptions <= UINT16_MAX &&
+           "Not enough bits to encode exceptions");
+    ExtraBits.NumExceptionType = NumExceptions;
 
     assert(hasExtraBitfields() && "missing trailing extra bitfields!");
     auto *exnSlot =
Index: clang/include/clang/AST/Type.h
===================================================================
--- clang/include/clang/AST/Type.h
+++ clang/include/clang/AST/Type.h
@@ -3953,7 +3953,7 @@
     /// The number of types in the exception specification.
     /// A whole unsigned is not needed here and according to
     /// [implimits] 8 bits would be enough here.
-    unsigned NumExceptionType = 0;
+    uint16_t NumExceptionType = 0;
   };
 
 protected:



Index: clang/lib/AST/Type.cpp
===================================================================
--- clang/lib/AST/Type.cpp
+++ clang/lib/AST/Type.cpp
@@ -3371,7 +3371,10 @@
   // Fill in the exception type array if present.
   if (getExceptionSpecType() == EST_Dynamic) {
     auto &ExtraBits = *getTrailingObjects<FunctionTypeExtraBitfields>();
-    ExtraBits.NumExceptionType = epi.ExceptionSpec.Exceptions.size();
+    auto NumExceptions = epi.ExceptionSpec.Exceptions.size();
+    assert(NumExceptions <= UINT16_MAX &&
+           "Not enough bits to encode exceptions");
+    ExtraBits.NumExceptionType = NumExceptions;
 
     assert(hasExtraBitfields() && "missing trailing extra bitfields!");
     auto *exnSlot =
Index: clang/include/clang/AST/Type.h
===================================================================
--- clang/include/clang/AST/Type.h
+++ clang/include/clang/AST/Type.h
@@ -3953,7 +3953,7 @@
     /// The number of types in the exception specification.
     /// A whole unsigned is not needed here and according to
     /// [implimits] 8 bits would be enough here.
-    unsigned NumExceptionType = 0;
+    uint16_t NumExceptionType = 0;
   };
 
 protected:

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