From 006186b25e2e8fc902211cc08bea285c38cc42f2 Mon Sep 17 00:00:00 2001 From: "Duncan P. N. Exon Smith" Date: Mon, 22 Feb 2016 22:24:22 +0000 Subject: [PATCH] Lex: Check for 0 buckets on header map construction Switch to using `isPowerOf2_32()` to check whether the buckets are a power of two, and as a side benefit reject loading a header map with no buckets. This is a follow-up to r261448. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@261585 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Lex/HeaderMap.cpp | 10 +++++----- unittests/Lex/HeaderMapTest.cpp | 9 +++++++++ 2 files changed, 14 insertions(+), 5 deletions(-) diff --git a/lib/Lex/HeaderMap.cpp b/lib/Lex/HeaderMap.cpp index 67b663158f..be0d477e8b 100644 --- a/lib/Lex/HeaderMap.cpp +++ b/lib/Lex/HeaderMap.cpp @@ -86,10 +86,10 @@ bool HeaderMapImpl::checkHeader(const llvm::MemoryBuffer &File, // Check the number of buckets. It should be a power of two, and there // should be enough space in the file for all of them. - auto NumBuckets = NeedsByteSwap - ? llvm::sys::getSwappedBytes(Header->NumBuckets) - : Header->NumBuckets; - if (NumBuckets & (NumBuckets - 1)) + uint32_t NumBuckets = NeedsByteSwap + ? llvm::sys::getSwappedBytes(Header->NumBuckets) + : Header->NumBuckets; + if (!llvm::isPowerOf2_32(NumBuckets)) return false; if (File.getBufferSize() < sizeof(HMapHeader) + sizeof(HMapBucket) * NumBuckets) @@ -208,7 +208,7 @@ StringRef HeaderMapImpl::lookupFilename(StringRef Filename, unsigned NumBuckets = getEndianAdjustedWord(Hdr.NumBuckets); // Don't probe infinitely. This should be checked before constructing. - assert(!(NumBuckets & (NumBuckets - 1)) && "Expected power of 2"); + assert(llvm::isPowerOf2_32(NumBuckets) && "Expected power of 2"); // Linearly probe the hash table. for (unsigned Bucket = HashHMapKey(Filename);; ++Bucket) { diff --git a/unittests/Lex/HeaderMapTest.cpp b/unittests/Lex/HeaderMapTest.cpp index e892170960..ad0579a236 100644 --- a/unittests/Lex/HeaderMapTest.cpp +++ b/unittests/Lex/HeaderMapTest.cpp @@ -143,6 +143,15 @@ TEST(HeaderMapTest, checkHeader3Buckets) { ASSERT_FALSE(HeaderMapImpl::checkHeader(*File.getBuffer(), NeedsSwap)); } +TEST(HeaderMapTest, checkHeader0Buckets) { + // Create with 1 bucket to avoid 0-sized arrays. + MapFile<1, 1> File; + File.init(); + File.Header.NumBuckets = 0; + bool NeedsSwap; + ASSERT_FALSE(HeaderMapImpl::checkHeader(*File.getBuffer(), NeedsSwap)); +} + TEST(HeaderMapTest, checkHeaderNotEnoughBuckets) { MapFile<1, 1> File; File.init(); -- 2.40.0