1 files changed, 86 insertions, 81 deletions

diff --git a/contrib/llvm/tools/clang/lib/Lex/HeaderMap.cpp b/contrib/llvm/tools/clang/lib/Lex/HeaderMap.cpp
index 09d5384..4cace5b 100644
--- a/contrib/llvm/tools/clang/lib/Lex/HeaderMap.cpp
+++ b/contrib/llvm/tools/clang/lib/Lex/HeaderMap.cpp
@@ -12,48 +12,20 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Lex/HeaderMap.h"
+#include "clang/Lex/HeaderMapTypes.h"
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/FileManager.h"
 #include "llvm/ADT/SmallString.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/MemoryBuffer.h"
-#include <cstdio>
+#include "llvm/Support/SwapByteOrder.h"
+#include "llvm/Support/Debug.h"
+#include <cstring>
 #include <memory>
 using namespace clang;
 
-//===----------------------------------------------------------------------===//
-// Data Structures and Manifest Constants
-//===----------------------------------------------------------------------===//
-
-enum {
-  HMAP_HeaderMagicNumber = ('h' << 24) | ('m' << 16) | ('a' << 8) | 'p',
-  HMAP_HeaderVersion = 1,
-
-  HMAP_EmptyBucketKey = 0
-};
-
-namespace clang {
-struct HMapBucket {
-  uint32_t Key;          // Offset (into strings) of key.
-
-  uint32_t Prefix;     // Offset (into strings) of value prefix.
-  uint32_t Suffix;     // Offset (into strings) of value suffix.
-};
-
-struct HMapHeader {
-  uint32_t Magic;           // Magic word, also indicates byte order.
-  uint16_t Version;         // Version number -- currently 1.
-  uint16_t Reserved;        // Reserved for future use - zero for now.
-  uint32_t StringsOffset;   // Offset to start of string pool.
-  uint32_t NumEntries;      // Number of entries in the string table.
-  uint32_t NumBuckets;      // Number of buckets (always a power of 2).
-  uint32_t MaxValueLength;  // Length of longest result path (excluding nul).
-  // An array of 'NumBuckets' HMapBucket objects follows this header.
-  // Strings follow the buckets, at StringsOffset.
-};
-} // end namespace clang.
-
 /// HashHMapKey - This is the 'well known' hash function required by the file
 /// format, used to look up keys in the hash table.  The hash table uses simple
 /// linear probing based on this function.
@@ -82,15 +54,25 @@ const HeaderMap *HeaderMap::Create(const FileEntry *FE, FileManager &FM) {
   if (FileSize <= sizeof(HMapHeader)) return nullptr;
 
   auto FileBuffer = FM.getBufferForFile(FE);
-  if (!FileBuffer) return nullptr;  // Unreadable file?
-  const char *FileStart = (*FileBuffer)->getBufferStart();
+  if (!FileBuffer || !*FileBuffer)
+    return nullptr;
+  bool NeedsByteSwap;
+  if (!checkHeader(**FileBuffer, NeedsByteSwap))
+    return nullptr;
+  return new HeaderMap(std::move(*FileBuffer), NeedsByteSwap);
+}
+
+bool HeaderMapImpl::checkHeader(const llvm::MemoryBuffer &File,
+                                bool &NeedsByteSwap) {
+  if (File.getBufferSize() <= sizeof(HMapHeader))
+    return false;
+  const char *FileStart = File.getBufferStart();
 
   // We know the file is at least as big as the header, check it now.
   const HMapHeader *Header = reinterpret_cast<const HMapHeader*>(FileStart);
 
   // Sniff it to see if it's a headermap by checking the magic number and
   // version.
-  bool NeedsByteSwap;
   if (Header->Magic == HMAP_HeaderMagicNumber &&
       Header->Version == HMAP_HeaderVersion)
     NeedsByteSwap = false;
@@ -98,12 +80,24 @@ const HeaderMap *HeaderMap::Create(const FileEntry *FE, FileManager &FM) {
            Header->Version == llvm::ByteSwap_16(HMAP_HeaderVersion))
     NeedsByteSwap = true;  // Mixed endianness headermap.
   else
-    return nullptr;  // Not a header map.
-
-  if (Header->Reserved != 0) return nullptr;
-
-  // Okay, everything looks good, create the header map.
-  return new HeaderMap(std::move(*FileBuffer), NeedsByteSwap);
+    return false;  // Not a header map.
+
+  if (Header->Reserved != 0)
+    return false;
+
+  // 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.
+  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)
+    return false;
+
+  // Okay, everything looks good.
+  return true;
 }
 
 //===----------------------------------------------------------------------===//
@@ -112,18 +106,18 @@ const HeaderMap *HeaderMap::Create(const FileEntry *FE, FileManager &FM) {
 
 
 /// getFileName - Return the filename of the headermap.
-const char *HeaderMap::getFileName() const {
+const char *HeaderMapImpl::getFileName() const {
   return FileBuffer->getBufferIdentifier();
 }
 
-unsigned HeaderMap::getEndianAdjustedWord(unsigned X) const {
+unsigned HeaderMapImpl::getEndianAdjustedWord(unsigned X) const {
   if (!NeedsBSwap) return X;
   return llvm::ByteSwap_32(X);
 }
 
 /// getHeader - Return a reference to the file header, in unbyte-swapped form.
 /// This method cannot fail.
-const HMapHeader &HeaderMap::getHeader() const {
+const HMapHeader &HeaderMapImpl::getHeader() const {
   // We know the file is at least as big as the header.  Return it.
   return *reinterpret_cast<const HMapHeader*>(FileBuffer->getBufferStart());
 }
@@ -131,42 +125,43 @@ const HMapHeader &HeaderMap::getHeader() const {
 /// getBucket - Return the specified hash table bucket from the header map,
 /// bswap'ing its fields as appropriate.  If the bucket number is not valid,
 /// this return a bucket with an empty key (0).
-HMapBucket HeaderMap::getBucket(unsigned BucketNo) const {
+HMapBucket HeaderMapImpl::getBucket(unsigned BucketNo) const {
+  assert(FileBuffer->getBufferSize() >=
+             sizeof(HMapHeader) + sizeof(HMapBucket) * BucketNo &&
+         "Expected bucket to be in range");
+
   HMapBucket Result;
   Result.Key = HMAP_EmptyBucketKey;
 
   const HMapBucket *BucketArray =
     reinterpret_cast<const HMapBucket*>(FileBuffer->getBufferStart() +
                                         sizeof(HMapHeader));
-
   const HMapBucket *BucketPtr = BucketArray+BucketNo;
-  if ((const char*)(BucketPtr+1) > FileBuffer->getBufferEnd()) {
-    Result.Prefix = 0;
-    Result.Suffix = 0;
-    return Result;  // Invalid buffer, corrupt hmap.
-  }
 
-  // Otherwise, the bucket is valid.  Load the values, bswapping as needed.
+  // Load the values, bswapping as needed.
   Result.Key    = getEndianAdjustedWord(BucketPtr->Key);
   Result.Prefix = getEndianAdjustedWord(BucketPtr->Prefix);
   Result.Suffix = getEndianAdjustedWord(BucketPtr->Suffix);
   return Result;
 }
 
-/// getString - Look up the specified string in the string table.  If the string
-/// index is not valid, it returns an empty string.
-const char *HeaderMap::getString(unsigned StrTabIdx) const {
+Optional<StringRef> HeaderMapImpl::getString(unsigned StrTabIdx) const {
   // Add the start of the string table to the idx.
   StrTabIdx += getEndianAdjustedWord(getHeader().StringsOffset);
 
   // Check for invalid index.
   if (StrTabIdx >= FileBuffer->getBufferSize())
-    return nullptr;
+    return None;
 
-  // Otherwise, we have a valid pointer into the file.  Just return it.  We know
-  // that the "string" can not overrun the end of the file, because the buffer
-  // is nul terminated by virtue of being a MemoryBuffer.
-  return FileBuffer->getBufferStart()+StrTabIdx;
+  const char *Data = FileBuffer->getBufferStart() + StrTabIdx;
+  unsigned MaxLen = FileBuffer->getBufferSize() - StrTabIdx;
+  unsigned Len = strnlen(Data, MaxLen);
+
+  // Check whether the buffer is null-terminated.
+  if (Len == MaxLen && Data[Len - 1])
+    return None;
+
+  return StringRef(Data, Len);
 }
 
 //===----------------------------------------------------------------------===//
@@ -174,22 +169,28 @@ const char *HeaderMap::getString(unsigned StrTabIdx) const {
 //===----------------------------------------------------------------------===//
 
 /// dump - Print the contents of this headermap to stderr.
-void HeaderMap::dump() const {
+LLVM_DUMP_METHOD void HeaderMapImpl::dump() const {
   const HMapHeader &Hdr = getHeader();
   unsigned NumBuckets = getEndianAdjustedWord(Hdr.NumBuckets);
 
-  fprintf(stderr, "Header Map %s:\n  %d buckets, %d entries\n",
-          getFileName(), NumBuckets,
-          getEndianAdjustedWord(Hdr.NumEntries));
+  llvm::dbgs() << "Header Map " << getFileName() << ":\n  " << NumBuckets
+               << ", " << getEndianAdjustedWord(Hdr.NumEntries) << "\n";
+
+  auto getStringOrInvalid = [this](unsigned Id) -> StringRef {
+    if (Optional<StringRef> S = getString(Id))
+      return *S;
+    return "<invalid>";
+  };
 
   for (unsigned i = 0; i != NumBuckets; ++i) {
     HMapBucket B = getBucket(i);
     if (B.Key == HMAP_EmptyBucketKey) continue;
 
-    const char *Key    = getString(B.Key);
-    const char *Prefix = getString(B.Prefix);
-    const char *Suffix = getString(B.Suffix);
-    fprintf(stderr, "  %d. %s -> '%s' '%s'\n", i, Key, Prefix, Suffix);
+    StringRef Key = getStringOrInvalid(B.Key);
+    StringRef Prefix = getStringOrInvalid(B.Prefix);
+    StringRef Suffix = getStringOrInvalid(B.Suffix);
+    llvm::dbgs() << "  " << i << ". " << Key << " -> '" << Prefix << "' '"
+                 << Suffix << "'\n";
   }
 }
 
@@ -199,22 +200,20 @@ const FileEntry *HeaderMap::LookupFile(
     StringRef Filename, FileManager &FM) const {
 
   SmallString<1024> Path;
-  StringRef Dest = lookupFilename(Filename, Path);
+  StringRef Dest = HeaderMapImpl::lookupFilename(Filename, Path);
   if (Dest.empty())
     return nullptr;
 
   return FM.getFile(Dest);
 }
 
-StringRef HeaderMap::lookupFilename(StringRef Filename,
-                                    SmallVectorImpl<char> &DestPath) const {
+StringRef HeaderMapImpl::lookupFilename(StringRef Filename,
+                                        SmallVectorImpl<char> &DestPath) const {
   const HMapHeader &Hdr = getHeader();
   unsigned NumBuckets = getEndianAdjustedWord(Hdr.NumBuckets);
 
-  // If the number of buckets is not a power of two, the headermap is corrupt.
-  // Don't probe infinitely.
-  if (NumBuckets & (NumBuckets-1))
-    return StringRef();
+  // Don't probe infinitely.  This should be checked before constructing.
+  assert(llvm::isPowerOf2_32(NumBuckets) && "Expected power of 2");
 
   // Linearly probe the hash table.
   for (unsigned Bucket = HashHMapKey(Filename);; ++Bucket) {
@@ -222,16 +221,22 @@ StringRef HeaderMap::lookupFilename(StringRef Filename,
     if (B.Key == HMAP_EmptyBucketKey) return StringRef(); // Hash miss.
 
     // See if the key matches.  If not, probe on.
-    if (!Filename.equals_lower(getString(B.Key)))
+    Optional<StringRef> Key = getString(B.Key);
+    if (LLVM_UNLIKELY(!Key))
+      continue;
+    if (!Filename.equals_lower(*Key))
       continue;
 
     // If so, we have a match in the hash table.  Construct the destination
     // path.
-    StringRef Prefix = getString(B.Prefix);
-    StringRef Suffix = getString(B.Suffix);
+    Optional<StringRef> Prefix = getString(B.Prefix);
+    Optional<StringRef> Suffix = getString(B.Suffix);
+
     DestPath.clear();
-    DestPath.append(Prefix.begin(), Prefix.end());
-    DestPath.append(Suffix.begin(), Suffix.end());
+    if (LLVM_LIKELY(Prefix && Suffix)) {
+      DestPath.append(Prefix->begin(), Prefix->end());
+      DestPath.append(Suffix->begin(), Suffix->end());
+    }
     return StringRef(DestPath.begin(), DestPath.size());
   }
 }