Bytecode format for LLVM 1.2 no longer explicitly encodes zeros in primitive
type planes. This saves about 5k on 176.gcc, and is needed for a subsequent
patch of mine I'm working on.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10908 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Bytecode/Reader/Reader.cpp b/lib/Bytecode/Reader/Reader.cpp
index 9cc24b3..16b4ee0 100644
--- a/lib/Bytecode/Reader/Reader.cpp
+++ b/lib/Bytecode/Reader/Reader.cpp
@@ -66,10 +66,17 @@
throw std::string("Illegal type reference!");
}
+static inline bool hasImplicitNull(unsigned TyID, bool EncodesPrimitiveZeros) {
+ if (!EncodesPrimitiveZeros)
+ return TyID != Type::LabelTyID && TyID != Type::TypeTyID &&
+ TyID != Type::VoidTyID;
+ return TyID >= Type::FirstDerivedTyID;
+}
+
unsigned BytecodeParser::insertValue(Value *Val, unsigned type,
ValueTable &ValueTab) {
- assert((!isa<Constant>(Val) || Val->getType()->isPrimitiveType() ||
- !cast<Constant>(Val)->isNullValue()) &&
+ assert((!isa<Constant>(Val) || !cast<Constant>(Val)->isNullValue()) ||
+ !hasImplicitNull(type, hasExplicitPrimitiveZeros) &&
"Cannot read null values from bytecode!");
assert(type != Type::TypeTyID && "Types should never be insertValue'd!");
@@ -88,13 +95,12 @@
return ValueTab[type]->size()-1 + HasOffset;
}
-
Value *BytecodeParser::getValue(unsigned type, unsigned oNum, bool Create) {
assert(type != Type::TypeTyID && "getValue() cannot get types!");
assert(type != Type::LabelTyID && "getValue() cannot get blocks!");
unsigned Num = oNum;
- if (type >= FirstDerivedTyID) {
+ if (hasImplicitNull(type, hasExplicitPrimitiveZeros)) {
if (Num == 0)
return Constant::getNullValue(getType(type));
--Num;
@@ -536,6 +542,7 @@
hasOldStyleVarargs = false;
hasVarArgCallPadding = false;
hasInconsistentModuleGlobalInfo = false;
+ hasExplicitPrimitiveZeros = false;
FirstDerivedTyID = 14;
switch (RevisionNum) {
@@ -545,16 +552,15 @@
hasExtendedLinkageSpecs = false;
hasOldStyleVarargs = true;
hasVarArgCallPadding = true;
- hasInconsistentModuleGlobalInfo = true;
-
- break;
+ // FALL THROUGH
case 0: // LLVM 1.0, 1.1 release version
// Compared to rev #2, we added support for weak linkage, a more dense
// encoding, and better varargs support.
// Base LLVM 1.0 bytecode format.
hasInconsistentModuleGlobalInfo = true;
- break;
+ hasExplicitPrimitiveZeros = true;
+ // FALL THROUGH
case 1: // LLVM 1.2 release version
// LLVM 1.2 added explicit support for emitting strings efficiently.
diff --git a/lib/Bytecode/Reader/ReaderInternals.h b/lib/Bytecode/Reader/ReaderInternals.h
index d6a934d..4c0b310 100644
--- a/lib/Bytecode/Reader/ReaderInternals.h
+++ b/lib/Bytecode/Reader/ReaderInternals.h
@@ -97,10 +97,16 @@
bool usesOldStyleVarargs; // Does this module USE old style varargs?
- // LLVM 1.0 & 1.1 had an explicit alignment of data only for the
- // ModuleGlobalInfo block. This was fixed to be like all other blocks in 1.2
+ // Flags to distinguish LLVM 1.0 & 1.1 bytecode formats (revision #0)
+
+ // Revision #0 had an explicit alignment of data only for the ModuleGlobalInfo
+ // block. This was fixed to be like all other blocks in 1.2
bool hasInconsistentModuleGlobalInfo;
+ // Revision #0 also explicitly encoded zero values for primitive types like
+ // int/sbyte/etc.
+ bool hasExplicitPrimitiveZeros;
+
typedef std::vector<ValueList*> ValueTable;
ValueTable Values;
ValueTable ModuleValues;
diff --git a/lib/Bytecode/Writer/SlotCalculator.cpp b/lib/Bytecode/Writer/SlotCalculator.cpp
index 766b000..2c6dd5e 100644
--- a/lib/Bytecode/Writer/SlotCalculator.cpp
+++ b/lib/Bytecode/Writer/SlotCalculator.cpp
@@ -406,6 +406,10 @@
return doInsertValue(D);
}
+static inline bool hasNullValue(unsigned TyID) {
+ return TyID != Type::LabelTyID && TyID != Type::TypeTyID &&
+ TyID != Type::VoidTyID;
+}
// doInsertValue - This is a small helper function to be called only
// be insertValue.
@@ -435,7 +439,7 @@
// If this is the first value to get inserted into the type plane, make sure
// to insert the implicit null value...
- if (Table[Ty].empty() && Ty >= Type::FirstDerivedTyID && BuildBytecodeInfo) {
+ if (Table[Ty].empty() && BuildBytecodeInfo && hasNullValue(Ty)) {
Value *ZeroInitializer = Constant::getNullValue(Typ);
// If we are pushing zeroinit, it will be handled below.
diff --git a/lib/Bytecode/Writer/Writer.cpp b/lib/Bytecode/Writer/Writer.cpp
index 6467921..ff9e8a9 100644
--- a/lib/Bytecode/Writer/Writer.cpp
+++ b/lib/Bytecode/Writer/Writer.cpp
@@ -161,6 +161,11 @@
}
}
+static inline bool hasNullValue(unsigned TyID) {
+ return TyID != Type::LabelTyID && TyID != Type::TypeTyID &&
+ TyID != Type::VoidTyID;
+}
+
void BytecodeWriter::outputConstants(bool isFunction) {
ConstantTotalBytes -= Out.size();
if (isFunction) FunctionConstantTotalBytes -= Out.size();
@@ -190,7 +195,7 @@
if (isFunction) // Don't re-emit module constants
ValNo += Table.getModuleLevel(pno);
- if (pno >= Type::FirstDerivedTyID) {
+ if (hasNullValue(pno)) {
// Skip zero initializer
if (ValNo == 0)
ValNo = 1;