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+//===- AVR.cpp ------------------------------------------------------------===//
+//
+// The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// AVR is a Harvard-architecture 8-bit micrcontroller designed for small
+// baremetal programs. All AVR-family processors have 32 8-bit registers.
+// The tiniest AVR has 32 byte RAM and 1 KiB program memory, and the largest
+// one supports up to 2^24 data address space and 2^22 code address space.
+//
+// Since it is a baremetal programming, there's usually no loader to load
+// ELF files on AVRs. You are expected to link your program against address
+// 0 and pull out a .text section from the result using objcopy, so that you
+// can write the linked code to on-chip flush memory. You can do that with
+// the following commands:
+//
+// ld.lld -Ttext=0 -o foo foo.o
+// objcopy -O binary --only-section=.text foo output.bin
+//
+// Note that the current AVR support is very preliminary so you can't
+// link any useful program yet, though.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Error.h"
+#include "InputFiles.h"
+#include "Memory.h"
+#include "Symbols.h"
+#include "Target.h"
+#include "llvm/Object/ELF.h"
+#include "llvm/Support/Endian.h"
+
+using namespace llvm;
+using namespace llvm::object;
+using namespace llvm::support::endian;
+using namespace llvm::ELF;
+using namespace lld;
+using namespace lld::elf;
+
+namespace {
+class AVR final : public TargetInfo {
+public:
+ RelExpr getRelExpr(uint32_t Type, const SymbolBody &S,
+ const uint8_t *Loc) const override;
+ void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
+};
+} // namespace
+
+RelExpr AVR::getRelExpr(uint32_t Type, const SymbolBody &S,
+ const uint8_t *Loc) const {
+ switch (Type) {
+ case R_AVR_CALL:
+ return R_ABS;
+ default:
+ error(toString(S.File) + ": unknown relocation type: " + toString(Type));
+ return R_HINT;
+ }
+}
+
+void AVR::relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const {
+ switch (Type) {
+ case R_AVR_CALL: {
+ uint16_t Hi = Val >> 17;
+ uint16_t Lo = Val >> 1;
+ write16le(Loc, read16le(Loc) | ((Hi >> 1) << 4) | (Hi & 1));
+ write16le(Loc + 2, Lo);
+ break;
+ }
+ default:
+ error(getErrorLocation(Loc) + "unrecognized reloc " + toString(Type));
+ }
+}
+
+TargetInfo *elf::createAVRTargetInfo() { return make<AVR>(); }