[MC][LoongArch] Make .reloc support arbitrary relocation types

Similar to D76746 (ARM), D76754 (AArch64), D77018 (RISCV)  and
llvmorg-11-init-6967-g152d14da64c (x86)

Differential Revision: https://reviews.llvm.org/D132119

4 files changed, 80 insertions, 1 deletions

diff --git a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp
index ea2c92b..dc98475 100644
--- a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp
+++ b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp
@@ -22,6 +22,22 @@
 
 using namespace llvm;
 
+Optional<MCFixupKind> LoongArchAsmBackend::getFixupKind(StringRef Name) const {
+  if (STI.getTargetTriple().isOSBinFormatELF()) {
+    auto Type = llvm::StringSwitch<unsigned>(Name)
+#define ELF_RELOC(X, Y) .Case(#X, Y)
+#include "llvm/BinaryFormat/ELFRelocs/LoongArch.def"
+#undef ELF_RELOC
+                    .Case("BFD_RELOC_NONE", ELF::R_LARCH_NONE)
+                    .Case("BFD_RELOC_32", ELF::R_LARCH_32)
+                    .Case("BFD_RELOC_64", ELF::R_LARCH_64)
+                    .Default(-1u);
+    if (Type != -1u)
+      return static_cast<MCFixupKind>(FirstLiteralRelocationKind + Type);
+  }
+  return None;
+}
+
 const MCFixupKindInfo &
 LoongArchAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
   const static MCFixupKindInfo Infos[] = {
@@ -38,6 +54,11 @@ LoongArchAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
   static_assert((array_lengthof(Infos)) == LoongArch::NumTargetFixupKinds,
                 "Not all fixup kinds added to Infos array");
 
+  // Fixup kinds from .reloc directive are like R_LARCH_NONE. They
+  // do not require any extra processing.
+  if (Kind >= FirstLiteralRelocationKind)
+    return MCAsmBackend::getFixupKindInfo(FK_NONE);
+
   if (Kind < FirstTargetFixupKind)
     return MCAsmBackend::getFixupKindInfo(Kind);
 
@@ -59,6 +80,8 @@ void LoongArchAsmBackend::applyFixup(const MCAssembler &Asm,
 bool LoongArchAsmBackend::shouldForceRelocation(const MCAssembler &Asm,
                                                 const MCFixup &Fixup,
                                                 const MCValue &Target) {
+  if (Fixup.getKind() >= FirstLiteralRelocationKind)
+    return true;
   // TODO: Determine which relocation require special processing at linking
   // time.
   return false;
diff --git a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.h b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.h
index 449554f..a69f8dc 100644
--- a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.h
+++ b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.h
@@ -23,12 +23,14 @@
 namespace llvm {
 
 class LoongArchAsmBackend : public MCAsmBackend {
+  const MCSubtargetInfo &STI;
   uint8_t OSABI;
   bool Is64Bit;
 
 public:
   LoongArchAsmBackend(const MCSubtargetInfo &STI, uint8_t OSABI, bool Is64Bit)
-      : MCAsmBackend(support::little), OSABI(OSABI), Is64Bit(Is64Bit) {}
+      : MCAsmBackend(support::little), STI(STI), OSABI(OSABI),
+        Is64Bit(Is64Bit) {}
   ~LoongArchAsmBackend() override {}
 
   void applyFixup(const MCAssembler &Asm, const MCFixup &Fixup,
@@ -49,6 +51,8 @@ public:
     return LoongArch::NumTargetFixupKinds;
   }
 
+  Optional<MCFixupKind> getFixupKind(StringRef Name) const override;
+
   const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override;
 
   void relaxInstruction(MCInst &Inst,
diff --git a/llvm/test/MC/LoongArch/Relocations/reloc-directive-err.s b/llvm/test/MC/LoongArch/Relocations/reloc-directive-err.s
new file mode 100644
index 0000000..e01209d
--- /dev/null
+++ b/llvm/test/MC/LoongArch/Relocations/reloc-directive-err.s
@@ -0,0 +1,6 @@
+# RUN: llvm-mc --triple=loongarch64 %s |& FileCheck --check-prefix=PRINT %s
+# RUN: not llvm-mc --filetype=obj --triple=loongarch64 %s -o /dev/null |& FileCheck %s
+
+# PRINT: .reloc 0, R_INVALID, 0
+# CHECK: {{.*}}.s:[[# @LINE+1]]:11: error: unknown relocation name
+.reloc 0, R_INVALID, 0
diff --git a/llvm/test/MC/LoongArch/Relocations/reloc-directive.s b/llvm/test/MC/LoongArch/Relocations/reloc-directive.s
new file mode 100644
index 0000000..f900f17c
--- /dev/null
+++ b/llvm/test/MC/LoongArch/Relocations/reloc-directive.s
@@ -0,0 +1,46 @@
+# RUN: llvm-mc --triple=loongarch64 %s | FileCheck --check-prefix=PRINT %s
+# RUN: llvm-mc --filetype=obj --triple=loongarch64 %s \
+# RUN:     | llvm-readobj -r - | FileCheck %s
+
+# PRINT: .reloc 8, R_LARCH_NONE, .data
+# PRINT: .reloc 4, R_LARCH_NONE, foo+4
+# PRINT: .reloc 0, R_LARCH_NONE, 8
+# PRINT: .reloc 0, R_LARCH_32, .data+2
+# PRINT: .reloc 0, R_LARCH_TLS_DTPMOD32, foo+3
+# PRINT: .reloc 0, R_LARCH_IRELATIVE, 5
+# PRINT:      .reloc 0, BFD_RELOC_NONE, 9
+# PRINT-NEXT: .reloc 0, BFD_RELOC_32, 9
+# PRINT-NEXT: .reloc 0, BFD_RELOC_64, 9
+
+.text
+  ret
+  nop
+  nop
+  .reloc 8, R_LARCH_NONE, .data
+  .reloc 4, R_LARCH_NONE, foo+4
+  .reloc 0, R_LARCH_NONE, 8
+
+  .reloc 0, R_LARCH_32, .data+2
+  .reloc 0, R_LARCH_TLS_DTPMOD32, foo+3
+  .reloc 0, R_LARCH_IRELATIVE, 5
+
+  .reloc 0, BFD_RELOC_NONE, 9
+  .reloc 0, BFD_RELOC_32, 9
+  .reloc 0, BFD_RELOC_64, 9
+
+.data
+.globl foo
+foo:
+  .word 0
+  .word 0
+  .word 0
+
+# CHECK:      0x8 R_LARCH_NONE .data 0x0
+# CHECK-NEXT: 0x4 R_LARCH_NONE foo 0x4
+# CHECK-NEXT: 0x0 R_LARCH_NONE - 0x8
+# CHECK-NEXT: 0x0 R_LARCH_32 .data 0x2
+# CHECK-NEXT: 0x0 R_LARCH_TLS_DTPMOD32 foo 0x3
+# CHECK-NEXT: 0x0 R_LARCH_IRELATIVE - 0x5
+# CHECK-NEXT: 0x0 R_LARCH_NONE - 0x9
+# CHECK-NEXT: 0x0 R_LARCH_32 - 0x9
+# CHECK-NEXT: 0x0 R_LARCH_64 - 0x9