[CodeGen][StaticDataSplitter]Support constant pool partitioning (#129781)

This is a follow-up patch of
https://github.com/llvm/llvm-project/pull/125756

In this PR, static-data-splitter pass produces the aggregated profile
counts of constants for constant pools in a global state
(`StateDataProfileInfo`), and asm printer consumes the profile counts to
produce `.hot` or `.unlikely` prefixes.

This implementation covers both x86 and aarch64 asm printer.

1 files changed, 35 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index dd6d85e..4c20c5d 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -1068,6 +1068,41 @@ MCSection *TargetLoweringObjectFileELF::getSectionForConstant(
   return DataRelROSection;
 }
 
+MCSection *TargetLoweringObjectFileELF::getSectionForConstant(
+    const DataLayout &DL, SectionKind Kind, const Constant *C, Align &Alignment,
+    StringRef SectionSuffix) const {
+  // TODO: Share code between this function and
+  // MCObjectInfo::initELFMCObjectFileInfo.
+  if (SectionSuffix.empty())
+    return getSectionForConstant(DL, Kind, C, Alignment);
+
+  auto &Context = getContext();
+  if (Kind.isMergeableConst4() && MergeableConst4Section)
+    return Context.getELFSection(".rodata.cst4." + SectionSuffix,
+                                 ELF::SHT_PROGBITS,
+                                 ELF::SHF_ALLOC | ELF::SHF_MERGE, 4);
+  if (Kind.isMergeableConst8() && MergeableConst8Section)
+    return Context.getELFSection(".rodata.cst8." + SectionSuffix,
+                                 ELF::SHT_PROGBITS,
+                                 ELF::SHF_ALLOC | ELF::SHF_MERGE, 8);
+  if (Kind.isMergeableConst16() && MergeableConst16Section)
+    return Context.getELFSection(".rodata.cst16." + SectionSuffix,
+                                 ELF::SHT_PROGBITS,
+                                 ELF::SHF_ALLOC | ELF::SHF_MERGE, 16);
+  if (Kind.isMergeableConst32() && MergeableConst32Section)
+    return Context.getELFSection(".rodata.cst32." + SectionSuffix,
+                                 ELF::SHT_PROGBITS,
+                                 ELF::SHF_ALLOC | ELF::SHF_MERGE, 32);
+  if (Kind.isReadOnly())
+    return Context.getELFSection(".rodata." + SectionSuffix, ELF::SHT_PROGBITS,
+                                 ELF::SHF_ALLOC);
+
+  assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
+  return Context.getELFSection(".data.rel.ro." + SectionSuffix,
+                               ELF::SHT_PROGBITS,
+                               ELF::SHF_ALLOC | ELF::SHF_WRITE);
+}
+
 /// Returns a unique section for the given machine basic block.
 MCSection *TargetLoweringObjectFileELF::getSectionForMachineBasicBlock(
     const Function &F, const MachineBasicBlock &MBB,