diff --git a/bolt/include/bolt/Core/FunctionLayout.h b/bolt/include/bolt/Core/FunctionLayout.h
--- a/bolt/include/bolt/Core/FunctionLayout.h
+++ b/bolt/include/bolt/Core/FunctionLayout.h
@@ -23,6 +23,7 @@
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/iterator.h"
+#include "llvm/ADT/iterator_range.h"
namespace llvm {
namespace bolt {
@@ -100,7 +101,10 @@
const FunctionLayout *Layout;
FragmentIterator(FragmentNum Num, const FunctionLayout *Layout)
- : Num(Num), Layout(Layout) {}
+ : Num(Num), Layout(Layout) {
+ assert(Num.get() <= Layout->fragment_size() &&
+ "Initializing iterator out of bounds");
+ }
public:
bool operator==(const FragmentIterator &Other) const {
@@ -108,15 +112,20 @@
}
FunctionFragment operator*() const {
+ assert(Num.get() < Layout->fragment_size() &&
+ "Dereferencing end() iterator (or past it)");
return FunctionFragment(Num, *Layout);
}
FragmentIterator &operator++() {
+ assert(Num.get() < Layout->fragment_size() &&
+ "Incrementing iterator past end()");
Num = FragmentNum(Num.get() + 1);
return *this;
}
FragmentIterator &operator--() {
+ assert(Num.get() > 0 && "Decrementing iterator past begin()");
Num = FragmentNum(Num.get() - 1);
return *this;
}
@@ -133,8 +142,9 @@
BasicBlockListType Blocks;
/// List of indices dividing block list into fragments. To simplify iteration,
/// we have `Fragments.back()` equals `Blocks.size()`. Hence,
- /// `Fragments.size()` equals `this->size() + 1`.
- FragmentListType Fragments = {0};
+ /// `Fragments.size()` equals `this->size() + 1`. Always contains at least one
+ /// fragment.
+ FragmentListType Fragments = {0, 0};
BasicBlockListType PreviousBlocks;
FragmentListType PreviousFragments;
@@ -188,14 +198,23 @@
/// layout after basic block reordering.
uint64_t getEditDistance() const;
- size_t size() const { return Fragments.size() - 1; }
- bool empty() const { return Fragments.size() == 1; }
- const_iterator begin() const { return {FragmentNum(0), this}; }
- const_iterator end() const { return {FragmentNum(size()), this}; }
- FunctionFragment front() const { return *begin(); }
- FunctionFragment back() const { return *std::prev(end()); }
- FunctionFragment operator[](const FragmentNum Num) const {
- return getFragment(Num);
+ /// True if the function is split into at most 2 fragments. Mostly used for
+ /// checking whether a function can be processed in places that do not support
+ /// multiple fragments yet.
+ bool isHotColdSplit() const { return fragment_size() <= 2; }
+
+ size_t fragment_size() const {
+ assert(Fragments.size() >= 2 &&
+ "Layout should have at least one fragment.");
+ return Fragments.size() - 1;
+ }
+ bool fragment_empty() const { return Fragments.size() == 1; }
+ const_iterator fragment_begin() const { return {FragmentNum(0), this}; }
+ const_iterator fragment_end() const {
+ return {FragmentNum(fragment_size()), this};
+ }
+ iterator_range<const_iterator> fragments() const {
+ return {fragment_begin(), fragment_end()};
}
size_t block_size() const { return Blocks.size(); }
diff --git a/bolt/lib/Core/BinaryEmitter.cpp b/bolt/lib/Core/BinaryEmitter.cpp
--- a/bolt/lib/Core/BinaryEmitter.cpp
+++ b/bolt/lib/Core/BinaryEmitter.cpp
@@ -15,6 +15,7 @@
#include "bolt/Core/BinaryContext.h"
#include "bolt/Core/BinaryFunction.h"
#include "bolt/Core/DebugData.h"
+#include "bolt/Core/FunctionLayout.h"
#include "bolt/Utils/CommandLineOpts.h"
#include "bolt/Utils/Utils.h"
#include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
@@ -396,12 +397,12 @@
if (!EmitCodeOnly && EmitColdPart && BF.hasConstantIsland())
BF.duplicateConstantIslands();
+ const FunctionFragment FF = BF.getLayout().getFragment(
+ EmitColdPart ? FragmentNum::cold() : FragmentNum::hot());
+
// Track the first emitted instruction with debug info.
bool FirstInstr = true;
- for (BinaryBasicBlock *BB : BF.getLayout().blocks()) {
- if (EmitColdPart != BB->isCold())
- continue;
-
+ for (BinaryBasicBlock *const BB : FF) {
if ((opts::AlignBlocks || opts::PreserveBlocksAlignment) &&
BB->getAlignment() > 1)
Streamer.emitCodeAlignment(BB->getAlignment(), &*BC.STI,
diff --git a/bolt/lib/Core/BinaryFunction.cpp b/bolt/lib/Core/BinaryFunction.cpp
--- a/bolt/lib/Core/BinaryFunction.cpp
+++ b/bolt/lib/Core/BinaryFunction.cpp
@@ -503,10 +503,10 @@
}
StringRef SplitPointMsg = "";
- for (const FunctionFragment F : Layout) {
+ for (const FunctionFragment FF : Layout.fragments()) {
OS << SplitPointMsg;
SplitPointMsg = "------- HOT-COLD SPLIT POINT -------\n\n";
- for (const BinaryBasicBlock *BB : F) {
+ for (const BinaryBasicBlock *BB : FF) {
OS << BB->getName() << " (" << BB->size()
<< " instructions, align : " << BB->getAlignment() << ")\n";
@@ -2782,12 +2782,12 @@
const char *Sep = "";
(void)Sep;
- for (const FunctionFragment F : Layout) {
+ for (const FunctionFragment FF : Layout.fragments()) {
// Hot-cold border: at start of each region (with a different FDE) we need
// to reset the CFI state.
int32_t State = 0;
- for (BinaryBasicBlock *BB : F) {
+ for (BinaryBasicBlock *BB : FF) {
const int32_t CFIStateAtExit = BB->getCFIStateAtExit();
// We need to recover the correct state if it doesn't match expected
diff --git a/bolt/lib/Core/FunctionLayout.cpp b/bolt/lib/Core/FunctionLayout.cpp
--- a/bolt/lib/Core/FunctionLayout.cpp
+++ b/bolt/lib/Core/FunctionLayout.cpp
@@ -20,7 +20,7 @@
FunctionFragment FunctionLayout::addFragment() {
Fragments.emplace_back(Blocks.size());
- return back();
+ return getFragment(FragmentNum(Blocks.size() - 1));
}
FunctionFragment FunctionLayout::getFragment(FragmentNum Num) const {
@@ -33,21 +33,14 @@
}
void FunctionLayout::addBasicBlock(BinaryBasicBlock *BB) {
- if (empty())
- addFragment();
-
BB->setLayoutIndex(Blocks.size());
Blocks.emplace_back(BB);
++Fragments.back();
-
assert(Fragments.back() == Blocks.size());
}
void FunctionLayout::insertBasicBlocks(BinaryBasicBlock *InsertAfter,
ArrayRef<BinaryBasicBlock *> NewBlocks) {
- if (empty())
- addFragment();
-
const block_iterator InsertBeforePos =
InsertAfter ? std::next(findBasicBlockPos(InsertAfter)) : Blocks.begin();
Blocks.insert(InsertBeforePos, NewBlocks.begin(), NewBlocks.end());
@@ -66,9 +59,9 @@
};
FragmentListType NewFragments;
NewFragments.emplace_back(0);
- for (const FunctionFragment F : *this) {
- unsigned ErasedBlocks = count_if(F, IsErased);
- unsigned NewFragment = NewFragments.back() + F.size() - ErasedBlocks;
+ for (const FunctionFragment FF : fragments()) {
+ unsigned ErasedBlocks = count_if(FF, IsErased);
+ unsigned NewFragment = NewFragments.back() + FF.size() - ErasedBlocks;
NewFragments.emplace_back(NewFragment);
}
llvm::erase_if(Blocks, IsErased);
@@ -77,8 +70,8 @@
void FunctionLayout::updateLayoutIndices() const {
unsigned BlockIndex = 0;
- for (const FunctionFragment F : *this) {
- for (BinaryBasicBlock *const BB : F)
+ for (const FunctionFragment FF : fragments()) {
+ for (BinaryBasicBlock *const BB : FF)
BB->setLayoutIndex(BlockIndex++);
}
}
@@ -88,7 +81,7 @@
PreviousFragments = std::move(Fragments);
Blocks.clear();
- Fragments = {0};
+ Fragments = {0, 0};
if (NewLayout.empty())
return;
@@ -99,12 +92,12 @@
for (const auto &BB : enumerate(Blocks)) {
unsigned FragmentNum = BB.value()->getFragmentNum().get();
- assert(FragmentNum + 1 >= size() &&
+ assert(FragmentNum >= fragment_size() - 1 &&
"Blocks must be arranged such that fragments are monotonically "
"increasing.");
// Add empty fragments if necessary
- for (unsigned I = size(); I <= FragmentNum; ++I) {
+ for (unsigned I = fragment_size(); I <= FragmentNum; ++I) {
addFragment();
Fragments[I] = BB.index();
}
@@ -123,9 +116,9 @@
void FunctionLayout::clear() {
Blocks = {};
- Fragments = {0};
+ Fragments = {0, 0};
PreviousBlocks = {};
- PreviousFragments = {0};
+ PreviousFragments = {0, 0};
}
BinaryBasicBlock *FunctionLayout::getBasicBlockAfter(const BinaryBasicBlock *BB,
@@ -147,7 +140,7 @@
bool FunctionLayout::isSplit() const {
unsigned NonEmptyFragCount = llvm::count_if(
- *this, [](const FunctionFragment &F) { return !F.empty(); });
+ fragments(), [](const FunctionFragment &FF) { return !FF.empty(); });
return NonEmptyFragCount >= 2;
}