Fix some links to C++11 feature papers in the Coding Standards

[oota-llvm.git] / lib / MC / WinCOFFObjectWriter.cpp

diff --git a/lib/MC/WinCOFFObjectWriter.cpp b/lib/MC/WinCOFFObjectWriter.cpp
index ed19b7ec69dd2519edf40e3ae0cf61ec6ac74cad..381fe0ee03c49538bb4eb5605a052b37decff591 100644 (file)
--- a/lib/MC/WinCOFFObjectWriter.cpp
+++ b/lib/MC/WinCOFFObjectWriter.cpp
@@ -468,24 +468,52 @@ void WinCOFFObjectWriter::DefineSymbol(MCSymbolData const &SymbolData,
   }
 }
 
+// Maximum offsets for different string table entry encodings.
+static const unsigned Max6DecimalOffset = 999999;
+static const unsigned Max7DecimalOffset = 9999999;
+static const uint64_t MaxBase64Offset = 0xFFFFFFFFFULL; // 64^6, including 0
+
+// Encode a string table entry offset in base 64, padded to 6 chars, and
+// prefixed with a double slash: '//AAAAAA', '//AAAAAB', ...
+// Buffer must be at least 8 bytes large. No terminating null appended.
+static void encodeBase64StringEntry(char* Buffer, uint64_t Value) {
+  assert(Value > Max7DecimalOffset && Value <= MaxBase64Offset &&
+         "Illegal section name encoding for value");
+
+  static const char Alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+                                 "abcdefghijklmnopqrstuvwxyz"
+                                 "0123456789+/";
+
+  Buffer[0] = '/';
+  Buffer[1] = '/';
+
+  char* Ptr = Buffer + 7;
+  for (unsigned i = 0; i < 6; ++i) {
+    unsigned Rem = Value % 64;
+    Value /= 64;
+    *(Ptr--) = Alphabet[Rem];
+  }
+}
+
 /// making a section real involves assigned it a number and putting
 /// name into the string table if needed
 void WinCOFFObjectWriter::MakeSectionReal(COFFSection &S, size_t Number) {
   if (S.Name.size() > COFF::NameSize) {
-    const unsigned Max6DecimalSize = 999999;
-    const unsigned Max7DecimalSize = 9999999;
     uint64_t StringTableEntry = Strings.insert(S.Name.c_str());
 
-    if (StringTableEntry <= Max6DecimalSize) {
+    if (StringTableEntry <= Max6DecimalOffset) {
       std::sprintf(S.Header.Name, "/%d", unsigned(StringTableEntry));
-    } else if (StringTableEntry <= Max7DecimalSize) {
+    } else if (StringTableEntry <= Max7DecimalOffset) {
       // With seven digits, we have to skip the terminating null. Because
       // sprintf always appends it, we use a larger temporary buffer.
       char buffer[9] = { };
       std::sprintf(buffer, "/%d", unsigned(StringTableEntry));
       std::memcpy(S.Header.Name, buffer, 8);
+    } else if (StringTableEntry <= MaxBase64Offset) {
+      // Starting with 10,000,000, offsets are encoded as base64.
+      encodeBase64StringEntry(S.Header.Name, StringTableEntry);
     } else {
-      report_fatal_error("COFF string table is greater than 9,999,999 bytes.");
+      report_fatal_error("COFF string table is greater than 64 GB.");
     }
   } else
     std::memcpy(S.Header.Name, S.Name.c_str(), S.Name.size());
@@ -636,6 +664,11 @@ void WinCOFFObjectWriter::RecordRelocation(const MCAssembler &Asm,
 
   const MCSymbol &Symbol = Target.getSymA()->getSymbol();
   const MCSymbol &A = Symbol.AliasedSymbol();
+  if (!Asm.hasSymbolData(A))
+    Asm.getContext().FatalError(
+        Fixup.getLoc(),
+        Twine("symbol '") + A.getName() + "' can not be undefined");
+
   MCSymbolData &A_SD = Asm.getSymbolData(A);
 
   MCSectionData const *SectionData = Fragment->getParent();