[BOLT] LongJmp: Fix hot text section alignment

[yota9]

Summary

The BinaryEmitter uses opts::AlignText value to align the hot text
section. Also check that the opts::AlignText is at least
equal opts::AlignFunctions for the same reason, as described in D121392.

Vladislav Khmelevsky,
Advanced Software Technology Lab, Huawei

[rafauler]

LGTM

bolt/lib/Passes/LongJmp.cpp

 #include "bolt/Passes/LongJmp.h"
 
 #define DEBUG_TYPE "longjmp"
 
 using namespace llvm;
 
 namespace opts {
 extern cl::OptionCategory BoltOptCategory;
+extern llvm::cl::opt<unsigned> AlignText;
 extern cl::opt<unsigned> AlignFunctions;
 extern cl::opt<bool> UseOldText;
 extern cl::opt<bool> HotFunctionsAtEnd;
 
 static cl::opt<bool>
 GroupStubs("group-stubs",
   cl::desc("share stubs across functions"),
   cl::init(true),
uint64_t LongJmpPass::tentativeLayoutRelocMode(
   CurrentIndex = 0;
   bool ColdLayoutDone = false;
   for (BinaryFunction *Func : SortedFunctions) {
     if (!ColdLayoutDone && CurrentIndex >= LastHotIndex) {
       DotAddress =
           tentativeLayoutRelocColdPart(BC, SortedFunctions, DotAddress);
       ColdLayoutDone = true;
       if (opts::HotFunctionsAtEnd)
-        DotAddress = alignTo(DotAddress, BC.PageAlign);
+        DotAddress = alignTo(DotAddress, opts::AlignText);
     }
 
     DotAddress = alignTo(DotAddress, BinaryFunction::MinAlign);
     uint64_t Pad =
         offsetToAlignment(DotAddress, llvm::Align(Func->getAlignment()));
     if (Pad <= Func->getMaxAlignmentBytes())
       DotAddress += Pad;
     HotAddresses[Func] = DotAddress;
void LongJmpPass::tentativeLayout(
   }
 
   // Relocation mode
   uint64_t EstimatedTextSize = tentativeLayoutRelocMode(BC, SortedFunctions, 0);
 
   // Initial padding
   if (opts::UseOldText && EstimatedTextSize <= BC.OldTextSectionSize) {
     DotAddress = BC.OldTextSectionAddress;
-    uint64_t Pad = offsetToAlignment(DotAddress, llvm::Align(BC.PageAlign));
+    uint64_t Pad = offsetToAlignment(DotAddress, llvm::Align(opts::AlignText));
     if (Pad + EstimatedTextSize <= BC.OldTextSectionSize)
       DotAddress += Pad;
   } else {
-    DotAddress = alignTo(BC.LayoutStartAddress, BC.PageAlign);
+    DotAddress = alignTo(BC.LayoutStartAddress, opts::AlignText);
   }
 
   tentativeLayoutRelocMode(BC, SortedFunctions, DotAddress);
 }
 
 bool LongJmpPass::usesStub(const BinaryFunction &Func,
                            const MCInst &Inst) const {
   const MCSymbol *TgtSym = Func.getBinaryContext().MIB->getTargetSymbol(Inst);

bolt/lib/Rewrite/RewriteInstance.cpp

void RewriteInstance::adjustCommandLineOptions() {
   if (opts::UseOldText && !BC->HasRelocations) {
     errs() << "BOLT-WARNING: cannot use old .text in non-relocation mode\n";
     opts::UseOldText = false;
   }
 
   if (!opts::AlignText.getNumOccurrences())
     opts::AlignText = BC->PageAlign;
 
+  if (opts::AlignText < opts::AlignFunctions)
+    opts::AlignText = (unsigned)opts::AlignFunctions;
+
   if (BC->isX86() && opts::Lite.getNumOccurrences() == 0 && !opts::StrictMode &&
       !opts::UseOldText)
     opts::Lite = true;
 
   if (opts::Lite && opts::UseOldText) {
     errs() << "BOLT-WARNING: cannot combine -lite with -use-old-text. "
               "Disabling -use-old-text.\n";
     opts::UseOldText = false;