1 files changed, 9 insertions, 14 deletions
diff --git a/contrib/llvm-project/llvm/lib/CodeGen/MachineFunctionSplitter.cpp b/contrib/llvm-project/llvm/lib/CodeGen/MachineFunctionSplitter.cpp
index fbc071536d22..38c1c56d2823 100644
--- a/contrib/llvm-project/llvm/lib/CodeGen/MachineFunctionSplitter.cpp
+++ b/contrib/llvm-project/llvm/lib/CodeGen/MachineFunctionSplitter.cpp
@@ -35,6 +35,7 @@
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/TargetInstrInfo.h"
 #include "llvm/IR/Function.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Support/CommandLine.h"
@@ -108,6 +109,12 @@ static bool isColdBlock(const MachineBasicBlock &MBB,
                         const MachineBlockFrequencyInfo *MBFI,
                         ProfileSummaryInfo *PSI) {
   std::optional<uint64_t> Count = MBFI->getBlockProfileCount(&MBB);
+
+  // Temporary hack to cope with AArch64's jump table encoding
+  const TargetInstrInfo &TII = *MBB.getParent()->getSubtarget().getInstrInfo();
+  if (!TII.isMBBSafeToSplitToCold(MBB))
+    return false;
+
   // For instrumentation profiles and sample profiles, we use different ways
   // to judge whether a block is cold and should be split.
   if (PSI->hasInstrumentationProfile() || PSI->hasCSInstrumentationProfile()) {
@@ -135,22 +142,10 @@ bool MachineFunctionSplitter::runOnMachineFunction(MachineFunction &MF) {
   if (!UseProfileData && !SplitAllEHCode)
     return false;
 
-  // TODO: We don't split functions where a section attribute has been set
-  // since the split part may not be placed in a contiguous region. It may also
-  // be more beneficial to augment the linker to ensure contiguous layout of
-  // split functions within the same section as specified by the attribute.
-  if (MF.getFunction().hasSection() ||
-      MF.getFunction().hasFnAttribute("implicit-section-name"))
+  const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
+  if (!TII.isFunctionSafeToSplit(MF))
     return false;
 
-  // We don't want to proceed further for cold functions
-  // or functions of unknown hotness. Lukewarm functions have no prefix.
-  std::optional<StringRef> SectionPrefix = MF.getFunction().getSectionPrefix();
-  if (SectionPrefix &&
-      (*SectionPrefix == "unlikely" || *SectionPrefix == "unknown")) {
-    return false;
-  }
-
   // Renumbering blocks here preserves the order of the blocks as
   // sortBasicBlocksAndUpdateBranches uses the numeric identifier to sort
   // blocks. Preserving the order of blocks is essential to retaining decisions