Add support for writing bytecode files with compactiontables for bytecode files.
This shrinks the bytecode file for 176.gcc by about 200K (10%), and 254.gap by
about 167K, a 25% reduction. There is still a lot of room for improvement in
the encoding of the compaction table.
llvm-svn: 10915
diff --git a/llvm/lib/Bytecode/Writer/Writer.cpp b/llvm/lib/Bytecode/Writer/Writer.cpp
index ff9e8a9..2fcc863 100644
--- a/llvm/lib/Bytecode/Writer/Writer.cpp
+++ b/llvm/lib/Bytecode/Writer/Writer.cpp
@@ -41,8 +41,6 @@
BytesWritten("bytecodewriter", "Number of bytecode bytes written");
static Statistic<>
ConstantTotalBytes("bytecodewriter", "Bytes of constants total");
-static Statistic<>
-FunctionConstantTotalBytes("bytecodewriter", "Bytes of function constants total");
static Statistic<>
ConstantPlaneHeaderBytes("bytecodewriter", "Constant plane header bytes");
static Statistic<>
@@ -51,6 +49,8 @@
SymTabBytes("bytecodewriter", "Bytes of symbol table");
static Statistic<>
ModuleInfoBytes("bytecodewriter", "Bytes of module info");
+static Statistic<>
+CompactionTableBytes("bytecodewriter", "Bytes of compaction tables");
BytecodeWriter::BytecodeWriter(std::deque<unsigned char> &o, const Module *M)
: Out(o), Table(M, true) {
@@ -168,7 +168,6 @@
void BytecodeWriter::outputConstants(bool isFunction) {
ConstantTotalBytes -= Out.size();
- if (isFunction) FunctionConstantTotalBytes -= Out.size();
BytecodeBlock CPool(BytecodeFormat::ConstantPool, Out,
true /* Elide block if empty */);
@@ -206,7 +205,6 @@
}
}
ConstantTotalBytes += Out.size();
- if (isFunction) FunctionConstantTotalBytes += Out.size();
}
static unsigned getEncodedLinkage(const GlobalValue *GV) {
@@ -257,32 +255,75 @@
ModuleInfoBytes += Out.size();
}
+void BytecodeWriter::outputInstructions(const Function *F) {
+ BytecodeBlock ILBlock(BytecodeFormat::InstructionList, Out);
+ InstructionBytes -= Out.size();
+ for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
+ for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E; ++I)
+ outputInstruction(*I);
+ InstructionBytes += Out.size();
+}
+
void BytecodeWriter::outputFunction(const Function *F) {
BytecodeBlock FunctionBlock(BytecodeFormat::Function, Out);
output_vbr(getEncodedLinkage(F), Out);
- // Only output the constant pool and other goodies if needed...
- if (!F->isExternal()) {
- // Get slot information about the function...
- Table.incorporateFunction(F);
+ // If this is an external function, there is nothing else to emit!
+ if (F->isExternal()) return;
- // Output information about the constants in the function...
+ // Get slot information about the function...
+ Table.incorporateFunction(F);
+
+ if (Table.getCompactionTable().empty()) {
+ // Output information about the constants in the function if the compaction
+ // table is not being used.
outputConstants(true);
-
- { // Output all of the instructions in the body of the function
- BytecodeBlock ILBlock(BytecodeFormat::InstructionList, Out);
- InstructionBytes -= Out.size();
- for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E;++BB)
- for(BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E;++I)
- processInstruction(*I);
- InstructionBytes += Out.size();
- }
-
- // If needed, output the symbol table for the function...
- outputSymbolTable(F->getSymbolTable());
-
- Table.purgeFunction();
+ } else {
+ // Otherwise, emit the compaction table.
+ outputCompactionTable();
}
+
+ // Output all of the instructions in the body of the function
+ outputInstructions(F);
+
+ // If needed, output the symbol table for the function...
+ outputSymbolTable(F->getSymbolTable());
+
+ Table.purgeFunction();
+}
+
+void BytecodeWriter::outputCompactionTablePlane(unsigned PlaneNo,
+ const std::vector<const Value*> &Plane,
+ unsigned StartNo) {
+ unsigned End = Table.getModuleLevel(PlaneNo);
+ if (StartNo == End || End == 0) return; // Nothing to emit
+ assert(StartNo < End && "Cannot emit negative range!");
+ assert(StartNo < Plane.size() && End <= Plane.size());
+
+ output_vbr(unsigned(End-StartNo), Out); // Output the number of things.
+ output_vbr(PlaneNo, Out); // Emit the type plane this is
+
+ // Do not emit the null initializer!
+ if (PlaneNo != Type::TypeTyID) ++StartNo;
+
+ for (unsigned i = StartNo; i != End; ++i)
+ output_vbr(Table.getGlobalSlot(Plane[i]), Out);
+}
+
+void BytecodeWriter::outputCompactionTable() {
+ CompactionTableBytes -= Out.size();
+ BytecodeBlock CTB(BytecodeFormat::CompactionTable, Out, true/*ElideIfEmpty*/);
+ const std::vector<std::vector<const Value*> > &CT =Table.getCompactionTable();
+
+ // First thing is first, emit the type compaction table if there is one.
+ if (CT.size() > Type::TypeTyID)
+ outputCompactionTablePlane(Type::TypeTyID, CT[Type::TypeTyID],
+ Type::FirstDerivedTyID);
+
+ for (unsigned i = 0, e = CT.size(); i != e; ++i)
+ if (i != Type::TypeTyID)
+ outputCompactionTablePlane(i, CT[i], 0);
+ CompactionTableBytes += Out.size();
}
void BytecodeWriter::outputSymbolTable(const SymbolTable &MST) {