[lld] [LLD] Merge .hexagon.attributes sections (PR #148098)

[Fangrui Song via llvm-commits]

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@@ -415,4 +422,117 @@ int64_t Hexagon::getImplicitAddend(const uint8_t *buf, RelType type) const {
   }
 }
 
+namespace {
+class HexagonAttributesSection final : public SyntheticSection {
+public:
+  HexagonAttributesSection(Ctx &ctx)
+      : SyntheticSection(ctx, ".hexagon.attributes", SHT_HEXAGON_ATTRIBUTES, 0,
+                         1) {}
+
+  size_t getSize() const override { return size; }
+  void writeTo(uint8_t *buf) override;
+
+  static constexpr StringRef vendor = "hexagon";
+  DenseMap<unsigned, unsigned> intAttr;
+  size_t size = 0;
+};
+} // namespace
+
+static HexagonAttributesSection *
+mergeAttributesSection(Ctx &ctx,
+                       const SmallVector<InputSectionBase *, 0> &sections) {
+  ctx.in.hexagonAttributes = std::make_unique<HexagonAttributesSection>(ctx);
+  auto &merged =
+      static_cast<HexagonAttributesSection &>(*ctx.in.hexagonAttributes);
+
+  // Collect all tags values from attributes section.
+  const auto &attributesTags = HexagonAttrs::getHexagonAttributeTags();
+  for (const InputSectionBase *sec : sections) {
+    HexagonAttributeParser parser;
+    if (Error e = parser.parse(sec->content(), llvm::endianness::little))
+      Warn(ctx) << sec << ": " << std::move(e);
+    for (const auto &tag : attributesTags) {
+      switch (HexagonAttrs::AttrType(tag.attr)) {
+      case HexagonAttrs::ARCH:
+      case HexagonAttrs::HVXARCH:
+        if (auto i = parser.getAttributeValue(tag.attr)) {
+          auto r = merged.intAttr.try_emplace(tag.attr, *i);
+          if (!r.second && r.first->second != *i) {
+            if (r.first->second < *i)
+              r.first->second = *i;
+          }
+        }
+        continue;
+
+      case HexagonAttrs::HVXIEEEFP:
+      case HexagonAttrs::HVXQFLOAT:
+      case HexagonAttrs::ZREG:
+      case HexagonAttrs::AUDIO:
+      case HexagonAttrs::CABAC:
+        if (auto i = parser.getAttributeValue(tag.attr)) {
+          auto r = merged.intAttr.try_emplace(tag.attr, *i);
+          if (!r.second && r.first->second != *i) {
----------------
MaskRay wrote:

drop braces for this single-line single-statement body. We can remove `&& r.first->second != *i`.

https://github.com/llvm/llvm-project/pull/148098