Begin adding experimental support for preserving use-list ordering of bitcode
files. First, add a new block USELIST_BLOCK to the bitcode format. This is
where USELIST_CODE_ENTRYs will be stored. The format of the USELIST_CODE_ENTRYs
have not yet been defined. Add support in the BitcodeReader for parsing the
USELIST_BLOCK.
Part of rdar://9860654 and PR5680.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146078 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index e758f94..48f60bc 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -23,6 +23,7 @@
#include "llvm/Operator.h"
#include "llvm/ValueSymbolTable.h"
#include "llvm/ADT/Triple.h"
+#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
@@ -31,6 +32,12 @@
#include <map>
using namespace llvm;
+static cl::opt<bool>
+EnablePreserveUseListOrdering("enable-bc-uselist-preserve",
+ cl::desc("Turn on experimental support for "
+ "use-list order preservation."),
+ cl::init(false), cl::Hidden);
+
/// These are manifest constants used by the bitcode writer. They do not need to
/// be kept in sync with the reader, but need to be consistent within this file.
enum {
@@ -1571,6 +1578,20 @@
Stream.ExitBlock();
}
+// Emit use-lists.
+static void WriteModuleUseLists(const Module *M, ValueEnumerator &VE,
+ BitstreamWriter &Stream) {
+ Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
+
+ // Emit a bogus record for testing purposes.
+ SmallVector<uint64_t, 64> Record;
+ Record.push_back(0);
+ Stream.EmitRecord(bitc::USELIST_CODE_ENTRY, Record);
+
+ // TODO: Tons.
+
+ Stream.ExitBlock();
+}
/// WriteModule - Emit the specified module to the bitstream.
static void WriteModule(const Module *M, BitstreamWriter &Stream) {
@@ -1616,6 +1637,10 @@
// Emit names for globals/functions etc.
WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
+ // Emit use-lists.
+ if (EnablePreserveUseListOrdering)
+ WriteModuleUseLists(M, VE, Stream);
+
Stream.ExitBlock();
}