[RISCV] Implement linker relaxation for R_RISCV_QC_ACCESS_16 and R_RISCV_QC_ACCESS_32

include/eld/Readers/ELFSection.h

@@ -320,6 +320,10 @@ class ELFSection : public ELFSectionBase {
   Relocation *findRelocation(uint64_t Offset, Relocation::Type Type,
                              bool Reverse = true) const;
 
+  // Returns true if R is immediately followed by a relocation of the given
+  // type in the section's relocation list.
+  bool hasFollowing(const Relocation *R, Relocation::Type Type) const;
+
   Relocation *createOneReloc();
 
   // Linker Script support for sorting sections.

lib/Readers/ELFSection.cpp

@@ -14,6 +14,7 @@
 #include "eld/Readers/ELFSection.h"
 #include "eld/Object/OutputSectionEntry.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/BinaryFormat/ELF.h"
 #include <sstream>
 
 using namespace eld;
@@ -178,6 +179,15 @@ Relocation *ELFSection::findRelocation(uint64_t Offset, Relocation::Type Type,
   return nullptr;
 }
 
+bool ELFSection::hasFollowing(const Relocation *R,
+                              Relocation::Type Type) const {
+  auto It = std::find(Relocations.begin(), Relocations.end(), R);
+  if (It == Relocations.end())
+    return false;
+  ++It;
+  return It != Relocations.end() && (*It)->type() == Type;
+}
+
 Fragment *ELFSection::getFirstFragmentInRule() const {
   OutputSectionEntry *OE = getOutputSection();
   if (!OE || !OE->size())

lib/Target/RISCV/RISCVHelper.h

@@ -333,6 +333,21 @@ template <typename T> T encodeQCEJ(T Result) {
   return Result;
 }
 
+template <typename T> T encodeQCEI(T Result) {
+  uint32_t Imm9_0 = extractBits(Result, 9, 0) << 20;
+  uint64_t Imm25_10 = static_cast<uint64_t>(extractBits(Result, 25, 10)) << 32;
+  Result = Imm9_0 | Imm25_10;
+  return Result;
+}
+
+template <typename T> T encodeQCES(T Result) {
+  uint32_t Imm4_0 = extractBits(Result, 4, 0) << 7;
+  uint32_t Imm9_5 = extractBits(Result, 9, 5) << 25;
+  uint64_t Imm25_10 = static_cast<uint64_t>(extractBits(Result, 25, 10)) << 32;
+  Result = Imm4_0 | Imm9_5 | Imm25_10;
+  return Result;
+}
+
 /// --------------------------------------------
 /// Fetch Registers and Opcode from Instruction
 /// --------------------------------------------