[LLD][Xtensa] Improve literal sections placement.

Improve sections sort to place literal section closer to code section which uses literals.
Fix l32r relocation check.

Author: andreisfr

lld/ELF/Arch/Xtensa.cpp

@@ -127,10 +127,12 @@ void Xtensa::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
     // Look at the instruction to determine how to do the relocation.
     uint8_t opcode = loc[0] & 0x0f;
     if (opcode == 0b0001) { // RI16 format: l32r
-      uint64_t val = dest - ((p + 3) & (uint64_t)0xfffffffc);
-      checkInt(loc, static_cast<int64_t>(val) >> 2, 16, rel);
-      checkAlignment(loc, val, 4, rel);
-      write16le(loc + 1, static_cast<int64_t>(val) >> 2);
+      int64_t val = dest - ((p + 3) & (uint64_t)0xfffffffc);
+      if ((val < -262144 || val > -4))
+        reportRangeError(loc, rel, Twine(static_cast<int64_t>(val)), -262141,
+                         -4);
+      checkAlignment(loc, static_cast<uint64_t>(val), 4, rel);
+      write16le(loc + 1, val >> 2);
     } else if (opcode == 0b0101) { // call0, call4, call8, call12 (CALL format)
       uint64_t val = dest - ((p + 4) & (uint64_t)0xfffffffc);
       checkInt(loc, static_cast<int64_t>(val) >> 2, 18, rel);

lld/ELF/Writer.cpp

@@ -31,6 +31,7 @@
 #include "llvm/Support/TimeProfiler.h"
 #include "llvm/Support/xxhash.h"
 #include <climits>
+#include <map>
 
 #define DEBUG_TYPE "lld"
 
@@ -1368,6 +1369,58 @@ sortISDBySectionOrder(InputSectionDescription *isd,
     isd->sections.push_back(isec);
 }
 
+// Sort Xtensa literal sections in OutputSection. For each literal section we try
+// to find by name text(code) section, which uses these literals. The literal
+// section should always be placed before code section.
+// Also we try to place literal section just before code section.
+static void sortSectionXtensa(OutputSection &osec) {
+  for (SectionCommand *b : osec.commands) {
+    if (auto *isd = dyn_cast<InputSectionDescription>(b)) {
+      std::map<std::string, int> orderedNames;
+      SmallVector<std::pair<InputSection *, int>, 0> orderedSections;
+      int sidx = 0;
+
+      for (InputSection *isec : isd->sections) {
+        if (orderedNames.count(isec->name.str())) {
+          orderedSections.push_back({isec, orderedNames[isec->name.str()]});
+          continue;
+        }
+        //Check if current section contains literals
+        if (isec->name.contains(".literal")) {
+          std::string literalName = isec->name.str();
+          std::size_t pos = literalName.find(".literal");
+          std::string textName;
+          // Reconstructing text(code) section name by literal section name
+          if (pos == 0) {
+            textName = ".text";
+          } else {
+            textName = literalName.substr(0, pos);
+          }
+          textName += literalName.substr(pos + 8, std::string::npos);
+          if (orderedNames.count(textName)) {
+            int textIdx = orderedNames[textName];
+            int literalIdx = textIdx - 1;
+            orderedSections.push_back({isec, literalIdx});
+            orderedNames[isec->name.str()] = literalIdx;
+          } else {
+            orderedSections.push_back({isec, sidx});
+            orderedNames[isec->name.str()] = sidx;
+          }
+        } else {
+          orderedSections.push_back({isec, sidx});
+          orderedNames[isec->name.str()] = sidx;
+        }
+        sidx += 2;
+      }
+
+      llvm::sort(orderedSections, llvm::less_second());
+      isd->sections.clear();
+      for (std::pair<InputSection *, int> p : orderedSections)
+        isd->sections.push_back(p.first);
+    }
+  }
+}
+
 static void sortSection(OutputSection &osec,
                         const DenseMap<const InputSectionBase *, int> &order) {
   StringRef name = osec.name;
@@ -1394,7 +1447,7 @@ static void sortSection(OutputSection &osec,
         sortISDBySectionOrder(isd, order, osec.flags & SHF_EXECINSTR);
 
   if (config->emachine == EM_XTENSA) {
-    osec.sort([](InputSectionBase *s) { return s->name.contains(".literal") ? 0 : 1; });
+    sortSectionXtensa(osec);
   }
 
   if (script->hasSectionsCommand)