[JITLink] Add support of R_X86_64_32S relocation

[StephenFan]

Summary

This patch supported the R_X86_64_32S relocation and add the Pointer32Signed generic edge kind.

[lhames]

LGTM. Thanks very much Stephen!

llvm/include/llvm/ExecutionEngine/JITLink/ELF_x86_64.h

 #include "llvm/ExecutionEngine/JITLink/JITLink.h"
 
 namespace llvm {
 namespace jitlink {
 
 namespace ELF_x86_64_Edges {
 enum ELFX86RelocationKind : Edge::Kind {
   Branch32 = Edge::FirstRelocation,
+  Pointer32Signed,
   Pointer64,
   PCRel32,
   PCRel32GOTLoad,
   PCRel32GOTLoadRelaxable,
   PCRel32REXGOTLoadRelaxable,
   PCRel64GOT,
   GOTOFF64,
   GOT64,

llvm/include/llvm/ExecutionEngine/JITLink/x86_64.h

enum EdgeKind_x86_64 : Edge::Kind {
   ///   Fixup <- Target + Addend : uint32
   ///
   /// Errors:
   ///   - The target must reside in the low 32-bits of the address space,
   ///     otherwise an out-of-range error will be returned.
   ///
   Pointer32,
 
+  /// A signed 32-bit pointer value relocation
+  ///
+  /// Fixup expression:
+  ///   Fixup <- Target + Addend : int32
+  ///
+  /// Errors:
+  ///   - The target must reside in the signed 32-bits([-2**31, 2**32 - 1]) of
+  ///   the address space, otherwise an out-of-range error will be returned.
+  Pointer32Signed,
+
   /// A 64-bit delta.
   ///
   /// Delta from the fixup to the target.
   ///
   /// Fixup expression:
   ///   Fixup <- Target - Fixup + Addend : int64
   ///
   Delta64,
inline Error applyFixup(LinkGraph &G, Block &B, const Edge &E,
   case Pointer32: {
     uint64_t Value = E.getTarget().getAddress() + E.getAddend();
     if (LLVM_LIKELY(isInRangeForImmU32(Value)))
       *(ulittle32_t *)FixupPtr = Value;
     else
       return makeTargetOutOfRangeError(G, B, E);
     break;
   }
+  case Pointer32Signed: {
+    int64_t Value = E.getTarget().getAddress() + E.getAddend();
+    if (LLVM_LIKELY(isInRangeForImmS32(Value)))
+      *(little32_t *)FixupPtr = Value;
+    else
+      return makeTargetOutOfRangeError(G, B, E);
+    break;
+  }
 
   case BranchPCRel32:
   case BranchPCRel32ToPtrJumpStub:
   case BranchPCRel32ToPtrJumpStubBypassable:
   case PCRel32GOTLoadRelaxable:
   case PCRel32GOTLoadREXRelaxable:
   case PCRel32TLVPLoadREXRelaxable: {
     int64_t Value =

llvm/lib/ExecutionEngine/JITLink/ELF_x86_64.cpp

 // This should become a template as the ELFFile is so a lot of this could become
 // generic
 class ELFLinkGraphBuilder_x86_64 : public ELFLinkGraphBuilder<object::ELF64LE> {
 private:
 
   static Expected<ELF_x86_64_Edges::ELFX86RelocationKind>
   getRelocationKind(const uint32_t Type) {
     switch (Type) {
+    case ELF::R_X86_64_32S:
+      return ELF_x86_64_Edges::ELFX86RelocationKind::Pointer32Signed;
     case ELF::R_X86_64_PC32:
       return ELF_x86_64_Edges::ELFX86RelocationKind::PCRel32;
     case ELF::R_X86_64_PC64:
     case ELF::R_X86_64_GOTPC64:
       return ELF_x86_64_Edges::ELFX86RelocationKind::Delta64;
     case ELF::R_X86_64_64:
       return ELF_x86_64_Edges::ELFX86RelocationKind::Pointer64;
     case ELF::R_X86_64_GOTPCREL:
for (auto &SecRef : Sections) {
         Edge::Kind Kind = Edge::Invalid;
         switch (*ELFRelocKind) {
         case PCRel32:
           Kind = x86_64::Delta32;
           break;
         case Delta64:
           Kind = x86_64::Delta64;
           break;
+        case Pointer32Signed:
+          Kind = x86_64::Pointer32Signed;
+          break;
         case Pointer64:
           Kind = x86_64::Pointer64;
           break;
         case PCRel32GOTLoad: {
           Kind = x86_64::RequestGOTAndTransformToDelta32;
           break;
         }
         case PCRel32REXGOTLoadRelaxable: {
if (auto Err = Ctx->modifyPassConfig(*G, Config))
     return Ctx->notifyFailed(std::move(Err));
 
   ELFJITLinker_x86_64::link(std::move(Ctx), std::move(G), std::move(Config));
 }
 const char *getELFX86RelocationKindName(Edge::Kind R) {
   switch (R) {
   case Branch32:
     return "Branch32";
+  case Pointer32Signed:
+    return "Pointer32Signed";
   case Pointer64:
     return "Pointer64";
   case PCRel32:
     return "PCRel32";
   case PCRel32GOTLoad:
     return "PCRel32GOTLoad";
   case PCRel32GOTLoadRelaxable:
     return "PCRel32GOTLoadRelaxable";

llvm/lib/ExecutionEngine/JITLink/x86_64.cpp

 namespace x86_64 {
 
 const char *getEdgeKindName(Edge::Kind K) {
   switch (K) {
   case Pointer64:
     return "Pointer64";
   case Pointer32:
     return "Pointer32";
+  case Pointer32Signed:
+    return "Pointer32Signed";
   case Delta64:
     return "Delta64";
   case Delta32:
     return "Delta32";
   case NegDelta64:
     return "NegDelta64";
   case NegDelta32:
     return "NegDelta32";

llvm/test/ExecutionEngine/JITLink/X86/ELF_x86_64_absolute_relocations.s

+# RUN: rm -rf %t && mkdir -p %t
+# RUN: llvm-mc -triple=x86_64-unknown-linux -position-independent -filetype=obj \
+# RUN:         -o %t/elf_abs_reloc.o %s
+# RUN: llvm-jitlink -noexec -slab-allocate 100Kb -slab-address 0xfff00000 \
+# RUN:              -define-abs external_data_low=0x1 \
+# RUN:              -define-abs external_data_high=0xffffffff80000000 \
+# RUN:              -check %s %t/elf_abs_reloc.o
+#
+# Test ELF absolute relocations.
+
+
+        .text
+        .file   "testcase.c"
+
+# Empty main entry point.
+        .globl  main
+        .p2align        4, 0x90
+        .type   main,@function
+main:
+        retq
+
+        .size   main, .-main
+
+# R_X86_64_32S handling
+# Test the target value is in range of signed 32-bits imm
+# jitlink-check: decode_operand(test_abs_32S, 4) = external_data_low
+# jitlink-check: decode_operand(test_abs_32S+7, 4)[31:0] = external_data_high[31:0]
+        .globl  test_abs_32S
+        .p2align       4, 0x90
+        .type   test_abs_32S,@function
+test_abs_32S:
+        movl    external_data_low, %eax
+        movl    external_data_high, %esi
+
+         .size   test_abs_32S, .-test_abs_32S