From 9df3605dea17e84f8183581f6103bd0c79e2a606 Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Sat, 1 Jul 2017 13:22:02 +0000
Subject: Vendor import of llvm trunk r306956:
 https://llvm.org/svn/llvm-project/llvm/trunk@306956

---
 lib/Bitcode/Reader/BitcodeReader.cpp | 32 ++++++++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 4 deletions(-)

(limited to 'lib/Bitcode/Reader/BitcodeReader.cpp')

diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 0629c2d326ae9..1ebef31731353 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -5360,8 +5360,9 @@ const std::error_category &llvm::BitcodeErrorCategory() {
   return *ErrorCategory;
 }
 
-static Expected<StringRef> readStrtab(BitstreamCursor &Stream) {
-  if (Stream.EnterSubBlock(bitc::STRTAB_BLOCK_ID))
+static Expected<StringRef> readBlobInRecord(BitstreamCursor &Stream,
+                                            unsigned Block, unsigned RecordID) {
+  if (Stream.EnterSubBlock(Block))
     return error("Invalid record");
 
   StringRef Strtab;
@@ -5382,7 +5383,7 @@ static Expected<StringRef> readStrtab(BitstreamCursor &Stream) {
     case BitstreamEntry::Record:
       StringRef Blob;
       SmallVector<uint64_t, 1> Record;
-      if (Stream.readRecord(Entry.ID, Record, &Blob) == bitc::STRTAB_BLOB)
+      if (Stream.readRecord(Entry.ID, Record, &Blob) == RecordID)
         Strtab = Blob;
       break;
     }
@@ -5450,7 +5451,8 @@ llvm::getBitcodeFileContents(MemoryBufferRef Buffer) {
       }
 
       if (Entry.ID == bitc::STRTAB_BLOCK_ID) {
-        Expected<StringRef> Strtab = readStrtab(Stream);
+        Expected<StringRef> Strtab =
+            readBlobInRecord(Stream, bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB);
         if (!Strtab)
           return Strtab.takeError();
         // This string table is used by every preceding bitcode module that does
@@ -5462,6 +5464,28 @@ llvm::getBitcodeFileContents(MemoryBufferRef Buffer) {
             break;
           I->Strtab = *Strtab;
         }
+        // Similarly, the string table is used by every preceding symbol table;
+        // normally there will be just one unless the bitcode file was created
+        // by binary concatenation.
+        if (!F.Symtab.empty() && F.StrtabForSymtab.empty())
+          F.StrtabForSymtab = *Strtab;
+        continue;
+      }
+
+      if (Entry.ID == bitc::SYMTAB_BLOCK_ID) {
+        Expected<StringRef> SymtabOrErr =
+            readBlobInRecord(Stream, bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB);
+        if (!SymtabOrErr)
+          return SymtabOrErr.takeError();
+
+        // We can expect the bitcode file to have multiple symbol tables if it
+        // was created by binary concatenation. In that case we silently
+        // ignore any subsequent symbol tables, which is fine because this is a
+        // low level function. The client is expected to notice that the number
+        // of modules in the symbol table does not match the number of modules
+        // in the input file and regenerate the symbol table.
+        if (F.Symtab.empty())
+          F.Symtab = *SymtabOrErr;
         continue;
       }
 
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