[LLVM][Alignment] Make functions using log of alignment explicit
Summary:
This patch renames functions that takes or returns alignment as log2, this patch will help with the transition to llvm::Align.
The renaming makes it explicit that we deal with log(alignment) instead of a power of two alignment.
A few renames uncovered dubious assignments:
- `MirParser`/`MirPrinter` was expecting powers of two but `MachineFunction` and `MachineBasicBlock` were using deal with log2(align). This patch fixes it and updates the documentation.
- `MachineBlockPlacement` exposes two flags (`align-all-blocks` and `align-all-nofallthru-blocks`) supposedly interpreted as power of two alignments, internally these values are interpreted as log2(align). This patch updates the documentation,
- `MachineFunctionexposes` exposes `align-all-functions` also interpreted as power of two alignment, internally this value is interpreted as log2(align). This patch updates the documentation,
Reviewers: lattner, thegameg, courbet
Subscribers: dschuff, arsenm, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, javed.absar, hiraditya, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, PkmX, jocewei, jsji, Jim, s.egerton, llvm-commits, courbet
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65945
llvm-svn: 371045
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 220c475..bf0be8e 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -667,7 +667,7 @@
EmitLinkage(&F, CurrentFnSym);
if (MAI->hasFunctionAlignment())
- EmitAlignment(MF->getAlignment(), &F);
+ EmitAlignment(MF->getLogAlignment(), &F);
if (MAI->hasDotTypeDotSizeDirective())
OutStreamer->EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
@@ -2905,8 +2905,8 @@
}
// Emit an alignment directive for this block, if needed.
- if (unsigned Align = MBB.getAlignment())
- EmitAlignment(Align);
+ if (unsigned LogAlign = MBB.getLogAlignment())
+ EmitAlignment(LogAlign);
MCCodePaddingContext Context;
setupCodePaddingContext(MBB, Context);
OutStreamer->EmitCodePaddingBasicBlockStart(Context);
diff --git a/llvm/lib/CodeGen/AsmPrinter/WinException.cpp b/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
index 155e91c..ef5aa04 100644
--- a/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
@@ -203,8 +203,8 @@
// We want our funclet's entry point to be aligned such that no nops will be
// present after the label.
- Asm->EmitAlignment(std::max(Asm->MF->getAlignment(), MBB.getAlignment()),
- &F);
+ Asm->EmitAlignment(
+ std::max(Asm->MF->getLogAlignment(), MBB.getLogAlignment()), &F);
// Now that we've emitted the alignment directive, point at our funclet.
Asm->OutStreamer->EmitLabel(Sym);
diff --git a/llvm/lib/CodeGen/BranchRelaxation.cpp b/llvm/lib/CodeGen/BranchRelaxation.cpp
index 55fbf01..4ee61cf 100644
--- a/llvm/lib/CodeGen/BranchRelaxation.cpp
+++ b/llvm/lib/CodeGen/BranchRelaxation.cpp
@@ -65,13 +65,13 @@
/// block.
unsigned postOffset(const MachineBasicBlock &MBB) const {
unsigned PO = Offset + Size;
- unsigned Align = MBB.getAlignment();
- if (Align == 0)
+ unsigned LogAlign = MBB.getLogAlignment();
+ if (LogAlign == 0)
return PO;
- unsigned AlignAmt = 1 << Align;
- unsigned ParentAlign = MBB.getParent()->getAlignment();
- if (Align <= ParentAlign)
+ unsigned AlignAmt = 1 << LogAlign;
+ unsigned ParentLogAlign = MBB.getParent()->getLogAlignment();
+ if (LogAlign <= ParentLogAlign)
return PO + OffsetToAlignment(PO, AlignAmt);
// The alignment of this MBB is larger than the function's alignment, so we
@@ -128,9 +128,9 @@
#ifndef NDEBUG
unsigned PrevNum = MF->begin()->getNumber();
for (MachineBasicBlock &MBB : *MF) {
- unsigned Align = MBB.getAlignment();
+ unsigned LogAlign = MBB.getLogAlignment();
unsigned Num = MBB.getNumber();
- assert(BlockInfo[Num].Offset % (1u << Align) == 0);
+ assert(BlockInfo[Num].Offset % (1u << LogAlign) == 0);
assert(!Num || BlockInfo[PrevNum].postOffset(MBB) <= BlockInfo[Num].Offset);
assert(BlockInfo[Num].Size == computeBlockSize(MBB));
PrevNum = Num;
diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index a8fa2f1..f8c4dd6 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -641,7 +641,7 @@
return error(Loc, Twine("redefinition of machine basic block with id #") +
Twine(ID));
if (Alignment)
- MBB->setAlignment(Alignment);
+ MBB->setLogAlignment(Log2_32(Alignment));
if (HasAddressTaken)
MBB->setHasAddressTaken();
MBB->setIsEHPad(IsLandingPad);
diff --git a/llvm/lib/CodeGen/MIRParser/MIRParser.cpp b/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
index 48ec0b2..2dd4fd3 100644
--- a/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
@@ -393,7 +393,7 @@
}
if (YamlMF.Alignment)
- MF.setAlignment(YamlMF.Alignment);
+ MF.setLogAlignment(Log2_32(YamlMF.Alignment));
MF.setExposesReturnsTwice(YamlMF.ExposesReturnsTwice);
MF.setHasWinCFI(YamlMF.HasWinCFI);
diff --git a/llvm/lib/CodeGen/MIRPrinter.cpp b/llvm/lib/CodeGen/MIRPrinter.cpp
index 7febb11..18efe1f 100644
--- a/llvm/lib/CodeGen/MIRPrinter.cpp
+++ b/llvm/lib/CodeGen/MIRPrinter.cpp
@@ -197,7 +197,7 @@
yaml::MachineFunction YamlMF;
YamlMF.Name = MF.getName();
- YamlMF.Alignment = MF.getAlignment();
+ YamlMF.Alignment = 1UL << MF.getLogAlignment();
YamlMF.ExposesReturnsTwice = MF.exposesReturnsTwice();
YamlMF.HasWinCFI = MF.hasWinCFI();
@@ -629,9 +629,10 @@
OS << "landing-pad";
HasAttributes = true;
}
- if (MBB.getAlignment()) {
+ if (MBB.getLogAlignment()) {
OS << (HasAttributes ? ", " : " (");
- OS << "align " << MBB.getAlignment();
+ OS << "align "
+ << (1UL << MBB.getLogAlignment());
HasAttributes = true;
}
if (HasAttributes)
diff --git a/llvm/lib/CodeGen/MachineBasicBlock.cpp b/llvm/lib/CodeGen/MachineBasicBlock.cpp
index 050934d..bd2ab45 100644
--- a/llvm/lib/CodeGen/MachineBasicBlock.cpp
+++ b/llvm/lib/CodeGen/MachineBasicBlock.cpp
@@ -326,9 +326,9 @@
OS << "landing-pad";
HasAttributes = true;
}
- if (getAlignment()) {
+ if (getLogAlignment()) {
OS << (HasAttributes ? ", " : " (");
- OS << "align " << getAlignment();
+ OS << "align " << getLogAlignment();
HasAttributes = true;
}
if (HasAttributes)
diff --git a/llvm/lib/CodeGen/MachineBlockPlacement.cpp b/llvm/lib/CodeGen/MachineBlockPlacement.cpp
index 641f14d..f2a64fa 100644
--- a/llvm/lib/CodeGen/MachineBlockPlacement.cpp
+++ b/llvm/lib/CodeGen/MachineBlockPlacement.cpp
@@ -79,16 +79,17 @@
STATISTIC(UncondBranchTakenFreq,
"Potential frequency of taking unconditional branches");
-static cl::opt<unsigned> AlignAllBlock("align-all-blocks",
- cl::desc("Force the alignment of all "
- "blocks in the function."),
- cl::init(0), cl::Hidden);
+static cl::opt<unsigned> AlignAllBlock(
+ "align-all-blocks",
+ cl::desc("Force the alignment of all blocks in the function in log2 format "
+ "(e.g 4 means align on 16B boundaries)."),
+ cl::init(0), cl::Hidden);
static cl::opt<unsigned> AlignAllNonFallThruBlocks(
"align-all-nofallthru-blocks",
- cl::desc("Force the alignment of all "
- "blocks that have no fall-through predecessors (i.e. don't add "
- "nops that are executed)."),
+ cl::desc("Force the alignment of all blocks that have no fall-through "
+ "predecessors (i.e. don't add nops that are executed). In log2 "
+ "format (e.g 4 means align on 16B boundaries)."),
cl::init(0), cl::Hidden);
// FIXME: Find a good default for this flag and remove the flag.
@@ -2763,8 +2764,8 @@
if (!L)
continue;
- unsigned Align = TLI->getPrefLoopAlignment(L);
- if (!Align)
+ unsigned LogAlign = TLI->getPrefLoopLogAlignment(L);
+ if (!LogAlign)
continue; // Don't care about loop alignment.
// If the block is cold relative to the function entry don't waste space
@@ -2788,7 +2789,7 @@
// Force alignment if all the predecessors are jumps. We already checked
// that the block isn't cold above.
if (!LayoutPred->isSuccessor(ChainBB)) {
- ChainBB->setAlignment(Align);
+ ChainBB->setLogAlignment(LogAlign);
continue;
}
@@ -2800,7 +2801,7 @@
MBPI->getEdgeProbability(LayoutPred, ChainBB);
BlockFrequency LayoutEdgeFreq = MBFI->getBlockFreq(LayoutPred) * LayoutProb;
if (LayoutEdgeFreq <= (Freq * ColdProb))
- ChainBB->setAlignment(Align);
+ ChainBB->setLogAlignment(LogAlign);
}
}
@@ -3062,14 +3063,14 @@
if (AlignAllBlock)
// Align all of the blocks in the function to a specific alignment.
for (MachineBasicBlock &MBB : MF)
- MBB.setAlignment(AlignAllBlock);
+ MBB.setLogAlignment(AlignAllBlock);
else if (AlignAllNonFallThruBlocks) {
// Align all of the blocks that have no fall-through predecessors to a
// specific alignment.
for (auto MBI = std::next(MF.begin()), MBE = MF.end(); MBI != MBE; ++MBI) {
auto LayoutPred = std::prev(MBI);
if (!LayoutPred->isSuccessor(&*MBI))
- MBI->setAlignment(AlignAllNonFallThruBlocks);
+ MBI->setLogAlignment(AlignAllNonFallThruBlocks);
}
}
if (ViewBlockLayoutWithBFI != GVDT_None &&
diff --git a/llvm/lib/CodeGen/MachineFunction.cpp b/llvm/lib/CodeGen/MachineFunction.cpp
index b771dd1..d136ebd 100644
--- a/llvm/lib/CodeGen/MachineFunction.cpp
+++ b/llvm/lib/CodeGen/MachineFunction.cpp
@@ -78,10 +78,11 @@
#define DEBUG_TYPE "codegen"
-static cl::opt<unsigned>
-AlignAllFunctions("align-all-functions",
- cl::desc("Force the alignment of all functions."),
- cl::init(0), cl::Hidden);
+static cl::opt<unsigned> AlignAllFunctions(
+ "align-all-functions",
+ cl::desc("Force the alignment of all functions in log2 format (e.g. 4 "
+ "means align on 16B boundaries)."),
+ cl::init(0), cl::Hidden);
static const char *getPropertyName(MachineFunctionProperties::Property Prop) {
using P = MachineFunctionProperties::Property;
@@ -172,16 +173,16 @@
FrameInfo->ensureMaxAlignment(F.getFnStackAlignment());
ConstantPool = new (Allocator) MachineConstantPool(getDataLayout());
- Alignment = STI->getTargetLowering()->getMinFunctionAlignment();
+ LogAlignment = STI->getTargetLowering()->getMinFunctionLogAlignment();
// FIXME: Shouldn't use pref alignment if explicit alignment is set on F.
// FIXME: Use Function::hasOptSize().
if (!F.hasFnAttribute(Attribute::OptimizeForSize))
- Alignment = std::max(Alignment,
- STI->getTargetLowering()->getPrefFunctionAlignment());
+ LogAlignment = std::max(
+ LogAlignment, STI->getTargetLowering()->getPrefFunctionLogAlignment());
if (AlignAllFunctions)
- Alignment = AlignAllFunctions;
+ LogAlignment = AlignAllFunctions;
JumpTableInfo = nullptr;
diff --git a/llvm/lib/CodeGen/PatchableFunction.cpp b/llvm/lib/CodeGen/PatchableFunction.cpp
index a3fa1b0..07f8859 100644
--- a/llvm/lib/CodeGen/PatchableFunction.cpp
+++ b/llvm/lib/CodeGen/PatchableFunction.cpp
@@ -78,7 +78,7 @@
MIB.add(MO);
FirstActualI->eraseFromParent();
- MF.ensureAlignment(4);
+ MF.ensureLogAlignment(4);
return true;
}
diff --git a/llvm/lib/CodeGen/TargetLoweringBase.cpp b/llvm/lib/CodeGen/TargetLoweringBase.cpp
index e9a7d4b..970b206 100644
--- a/llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -583,9 +583,9 @@
BooleanFloatContents = UndefinedBooleanContent;
BooleanVectorContents = UndefinedBooleanContent;
SchedPreferenceInfo = Sched::ILP;
- MinFunctionAlignment = 0;
- PrefFunctionAlignment = 0;
- PrefLoopAlignment = 0;
+ MinFunctionLogAlignment = 0;
+ PrefFunctionLogAlignment = 0;
+ PrefLoopLogAlignment = 0;
GatherAllAliasesMaxDepth = 18;
MinStackArgumentAlignment = 1;
// TODO: the default will be switched to 0 in the next commit, along