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-rw-r--r--llvm/lib/CodeGen/BasicBlockSections.cpp76
1 files changed, 42 insertions, 34 deletions
diff --git a/llvm/lib/CodeGen/BasicBlockSections.cpp b/llvm/lib/CodeGen/BasicBlockSections.cpp
index 3249022..8b6cf04 100644
--- a/llvm/lib/CodeGen/BasicBlockSections.cpp
+++ b/llvm/lib/CodeGen/BasicBlockSections.cpp
@@ -71,8 +71,8 @@
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
-#include "llvm/CodeGen/BasicBlockSectionsProfileReader.h"
#include "llvm/CodeGen/BasicBlockSectionUtils.h"
+#include "llvm/CodeGen/BasicBlockSectionsProfileReader.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/Passes.h"
@@ -131,9 +131,9 @@ INITIALIZE_PASS(BasicBlockSections, "bbsections-prepare",
// This function updates and optimizes the branching instructions of every basic
// block in a given function to account for changes in the layout.
-static void updateBranches(
- MachineFunction &MF,
- const SmallVector<MachineBasicBlock *, 4> &PreLayoutFallThroughs) {
+static void
+updateBranches(MachineFunction &MF,
+ const SmallVector<MachineBasicBlock *> &PreLayoutFallThroughs) {
const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo();
SmallVector<MachineOperand, 4> Cond;
for (auto &MBB : MF) {
@@ -168,7 +168,7 @@ static void updateBranches(
bool getBBClusterInfoForFunction(
const MachineFunction &MF,
BasicBlockSectionsProfileReader *BBSectionsProfileReader,
- std::vector<Optional<BBClusterInfo>> &V) {
+ DenseMap<unsigned, BBClusterInfo> &V) {
// Find the assoicated cluster information.
std::pair<bool, SmallVector<BBClusterInfo, 4>> P =
@@ -183,13 +183,8 @@ bool getBBClusterInfoForFunction(
return true;
}
- V.resize(MF.getNumBlockIDs());
- for (auto bbClusterInfo : P.second) {
- // Bail out if the cluster information contains invalid MBB numbers.
- if (bbClusterInfo.MBBNumber >= MF.getNumBlockIDs())
- return false;
- V[bbClusterInfo.MBBNumber] = bbClusterInfo;
- }
+ for (const BBClusterInfo &BBCI : P.second)
+ V[BBCI.BBID] = BBCI;
return true;
}
@@ -200,11 +195,12 @@ bool getBBClusterInfoForFunction(
// clusters, they are moved into a single "Exception" section. Eventually,
// clusters are ordered in increasing order of their IDs, with the "Exception"
// and "Cold" succeeding all other clusters.
-// FuncBBClusterInfo represent the cluster information for basic blocks. If this
-// is empty, it means unique sections for all basic blocks in the function.
+// FuncBBClusterInfo represent the cluster information for basic blocks. It
+// maps from BBID of basic blocks to their cluster information. If this is
+// empty, it means unique sections for all basic blocks in the function.
static void
assignSections(MachineFunction &MF,
- const std::vector<Optional<BBClusterInfo>> &FuncBBClusterInfo) {
+ const DenseMap<unsigned, BBClusterInfo> &FuncBBClusterInfo) {
assert(MF.hasBBSections() && "BB Sections is not set for function.");
// This variable stores the section ID of the cluster containing eh_pads (if
// all eh_pads are one cluster). If more than one cluster contain eh_pads, we
@@ -219,15 +215,21 @@ assignSections(MachineFunction &MF,
if (MF.getTarget().getBBSectionsType() == llvm::BasicBlockSection::All ||
FuncBBClusterInfo.empty()) {
// If unique sections are desired for all basic blocks of the function, we
- // set every basic block's section ID equal to its number (basic block
- // id). This further ensures that basic blocks are ordered canonically.
- MBB.setSectionID({static_cast<unsigned int>(MBB.getNumber())});
- } else if (FuncBBClusterInfo[MBB.getNumber()])
- MBB.setSectionID(FuncBBClusterInfo[MBB.getNumber()]->ClusterID);
- else {
- // BB goes into the special cold section if it is not specified in the
- // cluster info map.
- MBB.setSectionID(MBBSectionID::ColdSectionID);
+ // set every basic block's section ID equal to its original position in
+ // the layout (which is equal to its number). This ensures that basic
+ // blocks are ordered canonically.
+ MBB.setSectionID(MBB.getNumber());
+ } else {
+ // TODO: Replace `getBBIDOrNumber` with `getBBID` once version 1 is
+ // deprecated.
+ auto I = FuncBBClusterInfo.find(MBB.getBBIDOrNumber());
+ if (I != FuncBBClusterInfo.end()) {
+ MBB.setSectionID(I->second.ClusterID);
+ } else {
+ // BB goes into the special cold section if it is not specified in the
+ // cluster info map.
+ MBB.setSectionID(MBBSectionID::ColdSectionID);
+ }
}
if (MBB.isEHPad() && EHPadsSectionID != MBB.getSectionID() &&
@@ -250,12 +252,14 @@ assignSections(MachineFunction &MF,
void llvm::sortBasicBlocksAndUpdateBranches(
MachineFunction &MF, MachineBasicBlockComparator MBBCmp) {
- SmallVector<MachineBasicBlock *, 4> PreLayoutFallThroughs(
- MF.getNumBlockIDs());
+ [[maybe_unused]] const MachineBasicBlock *EntryBlock = &MF.front();
+ SmallVector<MachineBasicBlock *> PreLayoutFallThroughs(MF.getNumBlockIDs());
for (auto &MBB : MF)
PreLayoutFallThroughs[MBB.getNumber()] = MBB.getFallThrough();
MF.sort(MBBCmp);
+ assert(&MF.front() == EntryBlock &&
+ "Entry block should not be displaced by basic block sections");
// Set IsBeginSection and IsEndSection according to the assigned section IDs.
MF.assignBeginEndSections();
@@ -318,11 +322,14 @@ bool BasicBlockSections::runOnMachineFunction(MachineFunction &MF) {
if (BBSectionsType == BasicBlockSection::List &&
hasInstrProfHashMismatch(MF))
return true;
-
- // Renumber blocks before sorting them for basic block sections. This is
- // useful during sorting, basic blocks in the same section will retain the
- // default order. This renumbering should also be done for basic block
- // labels to match the profiles with the correct blocks.
+ // Renumber blocks before sorting them. This is useful during sorting,
+ // basic blocks in the same section will retain the default order.
+ // This renumbering should also be done for basic block labels to match the
+ // profiles with the correct blocks.
+ // For LLVM_BB_ADDR_MAP versions 2 and higher, this renumbering serves
+ // the different purpose of accessing the original layout positions and
+ // finding the original fallthroughs.
+ // TODO: Change the above comment accordingly when version 1 is deprecated.
MF.RenumberBlocks();
if (BBSectionsType == BasicBlockSection::Labels) {
@@ -332,7 +339,8 @@ bool BasicBlockSections::runOnMachineFunction(MachineFunction &MF) {
BBSectionsProfileReader = &getAnalysis<BasicBlockSectionsProfileReader>();
- std::vector<Optional<BBClusterInfo>> FuncBBClusterInfo;
+ // Map from BBID of blocks to their cluster information.
+ DenseMap<unsigned, BBClusterInfo> FuncBBClusterInfo;
if (BBSectionsType == BasicBlockSection::List &&
!getBBClusterInfoForFunction(MF, BBSectionsProfileReader,
FuncBBClusterInfo))
@@ -372,8 +380,8 @@ bool BasicBlockSections::runOnMachineFunction(MachineFunction &MF) {
// If the two basic block are in the same section, the order is decided by
// their position within the section.
if (XSectionID.Type == MBBSectionID::SectionType::Default)
- return FuncBBClusterInfo[X.getNumber()]->PositionInCluster <
- FuncBBClusterInfo[Y.getNumber()]->PositionInCluster;
+ return FuncBBClusterInfo.lookup(X.getBBIDOrNumber()).PositionInCluster <
+ FuncBBClusterInfo.lookup(Y.getBBIDOrNumber()).PositionInCluster;
return X.getNumber() < Y.getNumber();
};
generated by cgit v1.1 at 2025-09-29 20:43:42 +0000