[llvm] r369557 - [BitcodeReader] Check if we can create a null constant for type.

[Florian Hahn via llvm-commits]

Author: fhahn
Date: Wed Aug 21 11:20:11 2019
New Revision: 369557

URL: http://llvm.org/viewvc/llvm-project?rev=369557&view=rev
Log:
[BitcodeReader] Check if we can create a null constant for type.

We cannot create null constants for certain types, e.g. VoidTy,
FunctionTy or LabelTy. getNullValue asserts if we pass in an
unsupported type. We should also check for opaque types, but I'm not
sure how.

This fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=14795.

Reviewers: t.p.northover, jfb, vsk

Reviewed By: vsk

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65897

Added:
    llvm/trunk/test/Bitcode/invalid-type-for-null-constant.ll
    llvm/trunk/test/Bitcode/invalid-type-for-null-constant.ll.bc   (with props)
Modified:
    llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp

Modified: llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp?rev=369557&r1=369556&r2=369557&view=diff
==============================================================================
--- llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp (original)
+++ llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp Wed Aug 21 11:20:11 2019
@@ -2377,6 +2377,8 @@ Error BitcodeReader::parseConstants() {
       CurTy = flattenPointerTypes(CurFullTy);
       continue;  // Skip the ValueList manipulation.
     case bitc::CST_CODE_NULL:      // NULL
+      if (CurTy->isVoidTy() || CurTy->isFunctionTy() || CurTy->isLabelTy())
+        return error("Invalid type for a constant null value");
       V = Constant::getNullValue(CurTy);
       break;
     case bitc::CST_CODE_INTEGER:   // INTEGER: [intval]

Added: llvm/trunk/test/Bitcode/invalid-type-for-null-constant.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Bitcode/invalid-type-for-null-constant.ll?rev=369557&view=auto
==============================================================================
--- llvm/trunk/test/Bitcode/invalid-type-for-null-constant.ll (added)
+++ llvm/trunk/test/Bitcode/invalid-type-for-null-constant.ll Wed Aug 21 11:20:11 2019
@@ -0,0 +1,6 @@
+; Bitcode with a CST_CODE_NULL with void type.
+
+; RUN: not llvm-dis %s.bc -o - 2>&1 | FileCheck %s
+
+; CHECK: error: Invalid type for a constant null value
+

Added: llvm/trunk/test/Bitcode/invalid-type-for-null-constant.ll.bc
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Bitcode/invalid-type-for-null-constant.ll.bc?rev=369557&view=auto
==============================================================================
Binary file - no diff available.

Propchange: llvm/trunk/test/Bitcode/invalid-type-for-null-constant.ll.bc
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