Add R_ARM_REL32 .

src/emucore/elf/ElfFile.hxx

@@ -96,6 +96,7 @@ class ElfFile {
     static constexpr uInt32 STT_NOTYPE = 0x00;
 
     static constexpr uInt32 R_ARM_ABS32 = 0x02;
+    static constexpr uInt32 R_ARM_REL32 = 0x03;
     static constexpr uInt32 R_ARM_THM_CALL = 0x0a;
     static constexpr uInt32 R_ARM_THM_JUMP24 = 0x1e;
     static constexpr uInt32 R_ARM_TARGET1 = 0x26;

src/emucore/elf/ElfLinker.cxx

@@ -438,7 +438,12 @@ void ElfLinker::applyRelocationToSection(const ElfFile::Relocation& relocation,
       "unable to relocate " + symbol.name + " in " + targetSection.name + ": target out of range"
     );
 
-  uInt8* target =
+  const uInt32 targetAddress =
+    getSegmentBase(targetSectionRelocated.segment) +
+    targetSectionRelocated.offset +
+    relocation.offset;
+
+  uInt8* const target =
     getSegmentDataRef(targetSectionRelocated.segment).get() +
     targetSectionRelocated.offset +
     relocation.offset;
@@ -453,6 +458,16 @@ void ElfLinker::applyRelocationToSection(const ElfFile::Relocation& relocation,
         break;
       }
 
+    case ElfFile::R_ARM_REL32:
+      {
+        uInt32 value = relocatedSymbol->value + relocation.addend.value_or(read32(target));
+        value |= (symbol.type == ElfFile::STT_FUNC ? 0x01 : 0);
+
+        write32(target, value - targetAddress);
+
+        break;
+      }
+
     case ElfFile::R_ARM_THM_CALL:
     case ElfFile::R_ARM_THM_JUMP24:
       {

src/emucore/elf/LinkerTest.cxx

@@ -688,6 +688,102 @@ TEST(ElfLinker, RodataSectionsGoToRodata) {
     EXPECT_EQ(segmentRead32(linker, SegmentType::rodata, 0x14), static_cast<uInt32>(0x12345679));
   }
 
+
+  TEST(ElfLinker, R_ARM_REL32_InsertsTheValueRelativeToTheTargetPosition_text) {
+    ElfFixture fixture(1000);
+    ElfLinker linker(0x00100000, 0x00200000, 0x00300000, fixture);
+
+    fixture
+      .addSection(".text.1", ElfFile::SHT_PROGBITS, 0, 0x10)
+      .addSection(".text.2", ElfFile::SHT_PROGBITS, 0x10, 0x10)
+      .addSymbol("foo", 0x12345678, ElfFile::SHN_ABS)
+      .addRelocation(2, 0, 0x04, ElfFile::R_ARM_REL32);
+
+    linker.link({});
+
+    EXPECT_EQ(segmentRead32(linker, SegmentType::text, 0x14), static_cast<uInt32>(0x12345678 - 0x00100014));
+  }
+
+  TEST(ElfLinker, R_ARM_REL32_InsertsTheValueRelativeToTheTargetPosition_data) {
+    ElfFixture fixture(1000);
+    ElfLinker linker(0x00100000, 0x00200000, 0x00300000, fixture);
+
+    fixture
+      .addSection(".data.1", ElfFile::SHT_PROGBITS, 0, 0x10)
+      .addSection(".data.2", ElfFile::SHT_PROGBITS, 0x10, 0x10)
+      .addSymbol("foo", 0x12345678, ElfFile::SHN_ABS)
+      .addRelocation(2, 0, 0x04, ElfFile::R_ARM_REL32);
+
+    linker.link({});
+
+    EXPECT_EQ(segmentRead32(linker, SegmentType::data, 0x14), static_cast<uInt32>(0x12345678 - 0x00200014));
+  }
+
+  TEST(ElfLinker, R_ARM_REL32_InsertsTheValueRelativeToTheTargetPosition_rodata) {
+    ElfFixture fixture(1000);
+    ElfLinker linker(0x00100000, 0x00200000, 0x00300000, fixture);
+
+    fixture
+      .addSection(".rodata.1", ElfFile::SHT_PROGBITS, 0, 0x10)
+      .addSection(".rodata.2", ElfFile::SHT_PROGBITS, 0x10, 0x10)
+      .addSymbol("foo", 0x12345678, ElfFile::SHN_ABS)
+      .addRelocation(2, 0, 0x04, ElfFile::R_ARM_REL32);
+
+    linker.link({});
+
+    EXPECT_EQ(segmentRead32(linker, SegmentType::rodata, 0x14), static_cast<uInt32>(0x12345678 - 0x00300014));
+  }
+
+  TEST(ElfLinker, R_ARM_REL32_AddsAddendToTarget) {
+    ElfFixture fixture(1000);
+    ElfLinker linker(0x00100000, 0x00200000, 0x00300000, fixture);
+
+    fixture
+      .addSection(".rodata.1", ElfFile::SHT_PROGBITS, 0, 0x10)
+      .addSection(".rodata.2", ElfFile::SHT_PROGBITS, 0x10, 0x10)
+      .addSymbol("foo", 0x12345678, ElfFile::SHN_ABS)
+      .addRelocation(2, 0, 0x04, ElfFile::R_ARM_REL32, -4);
+
+
+    linker.link({});
+
+    EXPECT_EQ(segmentRead32(linker, SegmentType::rodata, 0x14), static_cast<uInt32>(0x12345674 - 0x00300014));
+  }
+
+  TEST(ElfLinker, R_ARM_REL32_UsesExistingValueAsAddend) {
+    ElfFixture fixture(1000);
+
+    ElfLinker linker(0x00100000, 0x00200000, 0x00300000, fixture);
+
+    fixture
+      .addSection(".rodata.1", ElfFile::SHT_PROGBITS, 0, 0x10)
+      .addSection(".rodata.2", ElfFile::SHT_PROGBITS, 0x10, 0x10)
+      .addSymbol("foo", 0x12345678, ElfFile::SHN_ABS)
+      .addRelocation(2, 0, 0x04, ElfFile::R_ARM_REL32)
+      .write32(0x14, -4);
+
+
+    linker.link({});
+
+    EXPECT_EQ(segmentRead32(linker, SegmentType::rodata, 0x14), static_cast<uInt32>(0x12345674 - 0x00300014));
+  }
+
+  TEST(ElfLinker, R_ARM_REL32_SetsBit0IfTargetIsFunction) {
+    ElfFixture fixture(1000);
+    ElfLinker linker(0x00100000, 0x00200000, 0x00300000, fixture);
+
+    fixture
+      .addSection(".rodata.1", ElfFile::SHT_PROGBITS, 0, 0x10)
+      .addSection(".rodata.2", ElfFile::SHT_PROGBITS, 0x10, 0x10)
+      .addSymbol("foo", 0x12345678, ElfFile::SHN_ABS, ElfFile::STT_FUNC)
+      .addRelocation(2, 0, 0x04, ElfFile::R_ARM_REL32);
+
+
+    linker.link({});
+
+    EXPECT_EQ(segmentRead32(linker, SegmentType::rodata, 0x14), static_cast<uInt32>(0x12345679 - 0x00300014));
+  }
+
   TEST(ElfLinker, R_ARM_THM_CALL_PatchesOffset) {
     ElfFixture fixture(1000);
     ElfLinker linker(0x00100000, 0x00200000, 0x00300000, fixture);
@@ -854,7 +950,7 @@ TEST(ElfLinker, RodataSectionsGoToRodata) {
   }
 
   INSTANTIATE_TEST_SUITE_P(RelocationExceptionSuite, RelocationExceptionTest, testing::Values(
-    ElfFile::R_ARM_ABS32, ElfFile::R_ARM_TARGET1,
+    ElfFile::R_ARM_ABS32, ElfFile::R_ARM_TARGET1, ElfFile::R_ARM_REL32,
     ElfFile::R_ARM_THM_CALL, ElfFile::R_ARM_THM_JUMP24
   ));