1 files changed, 102 insertions, 1 deletions
diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp
index 40fa195f37909..079dc919928ad 100644
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp
@@ -15,14 +15,18 @@
 #include "RISCVMCTargetDesc.h"
 #include "Utils/RISCVBaseInfo.h"
 #include "llvm/BinaryFormat/ELF.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCSectionELF.h"
 #include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/Support/LEB128.h"
+#include "llvm/Support/RISCVAttributes.h"
 
 using namespace llvm;
 
 // This part is for ELF object output.
 RISCVTargetELFStreamer::RISCVTargetELFStreamer(MCStreamer &S,
                                                const MCSubtargetInfo &STI)
-    : RISCVTargetStreamer(S) {
+    : RISCVTargetStreamer(S), CurrentVendor("riscv") {
   MCAssembler &MCA = getStreamer().getAssembler();
   const FeatureBitset &Features = STI.getFeatureBits();
   auto &MAB = static_cast<RISCVAsmBackend &>(MCA.getBackend());
@@ -62,7 +66,104 @@ MCELFStreamer &RISCVTargetELFStreamer::getStreamer() {
 
 void RISCVTargetELFStreamer::emitDirectiveOptionPush() {}
 void RISCVTargetELFStreamer::emitDirectiveOptionPop() {}
+void RISCVTargetELFStreamer::emitDirectiveOptionPIC() {}
+void RISCVTargetELFStreamer::emitDirectiveOptionNoPIC() {}
 void RISCVTargetELFStreamer::emitDirectiveOptionRVC() {}
 void RISCVTargetELFStreamer::emitDirectiveOptionNoRVC() {}
 void RISCVTargetELFStreamer::emitDirectiveOptionRelax() {}
 void RISCVTargetELFStreamer::emitDirectiveOptionNoRelax() {}
+
+void RISCVTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
+  setAttributeItem(Attribute, Value, /*OverwriteExisting=*/true);
+}
+
+void RISCVTargetELFStreamer::emitTextAttribute(unsigned Attribute,
+                                               StringRef String) {
+  setAttributeItem(Attribute, String, /*OverwriteExisting=*/true);
+}
+
+void RISCVTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
+                                                  unsigned IntValue,
+                                                  StringRef StringValue) {
+  setAttributeItems(Attribute, IntValue, StringValue,
+                    /*OverwriteExisting=*/true);
+}
+
+void RISCVTargetELFStreamer::finishAttributeSection() {
+  if (Contents.empty())
+    return;
+
+  if (AttributeSection) {
+    Streamer.SwitchSection(AttributeSection);
+  } else {
+    MCAssembler &MCA = getStreamer().getAssembler();
+    AttributeSection = MCA.getContext().getELFSection(
+        ".riscv.attributes", ELF::SHT_RISCV_ATTRIBUTES, 0);
+    Streamer.SwitchSection(AttributeSection);
+
+    Streamer.emitInt8(ELFAttrs::Format_Version);
+  }
+
+  // Vendor size + Vendor name + '\0'
+  const size_t VendorHeaderSize = 4 + CurrentVendor.size() + 1;
+
+  // Tag + Tag Size
+  const size_t TagHeaderSize = 1 + 4;
+
+  const size_t ContentsSize = calculateContentSize();
+
+  Streamer.emitInt32(VendorHeaderSize + TagHeaderSize + ContentsSize);
+  Streamer.emitBytes(CurrentVendor);
+  Streamer.emitInt8(0); // '\0'
+
+  Streamer.emitInt8(ELFAttrs::File);
+  Streamer.emitInt32(TagHeaderSize + ContentsSize);
+
+  // Size should have been accounted for already, now
+  // emit each field as its type (ULEB or String).
+  for (AttributeItem item : Contents) {
+    Streamer.emitULEB128IntValue(item.Tag);
+    switch (item.Type) {
+    default:
+      llvm_unreachable("Invalid attribute type");
+    case AttributeType::Numeric:
+      Streamer.emitULEB128IntValue(item.IntValue);
+      break;
+    case AttributeType::Text:
+      Streamer.emitBytes(item.StringValue);
+      Streamer.emitInt8(0); // '\0'
+      break;
+    case AttributeType::NumericAndText:
+      Streamer.emitULEB128IntValue(item.IntValue);
+      Streamer.emitBytes(item.StringValue);
+      Streamer.emitInt8(0); // '\0'
+      break;
+    }
+  }
+
+  Contents.clear();
+}
+
+size_t RISCVTargetELFStreamer::calculateContentSize() const {
+  size_t Result = 0;
+  for (AttributeItem item : Contents) {
+    switch (item.Type) {
+    case AttributeType::Hidden:
+      break;
+    case AttributeType::Numeric:
+      Result += getULEB128Size(item.Tag);
+      Result += getULEB128Size(item.IntValue);
+      break;
+    case AttributeType::Text:
+      Result += getULEB128Size(item.Tag);
+      Result += item.StringValue.size() + 1; // string + '\0'
+      break;
+    case AttributeType::NumericAndText:
+      Result += getULEB128Size(item.Tag);
+      Result += getULEB128Size(item.IntValue);
+      Result += item.StringValue.size() + 1; // string + '\0';
+      break;
+    }
+  }
+  return Result;
+}