ReaderWriter: teach the writer about IMAGE_REL_ARM_ADDR32

This implements the IMAGE_REL_ARM_ADDR32 relocation.  There are still a few more
relocation types that need to resolved before lld can even attempt to link a
trivial program for Windows on ARM.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@225057 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 93 insertions, 4 deletions

diff --git a/lib/ReaderWriter/PECOFF/WriterPECOFF.cpp b/lib/ReaderWriter/PECOFF/WriterPECOFF.cpp
index 06d1c030b..0df42314e 100644
--- a/lib/ReaderWriter/PECOFF/WriterPECOFF.cpp
+++ b/lib/ReaderWriter/PECOFF/WriterPECOFF.cpp
@@ -547,10 +547,31 @@ static uint32_t getSectionStartAddr(uint64_t targetAddr,
   llvm_unreachable("Section missing");
 }
 
-void AtomChunk::applyRelocationsARM(uint8_t *buffer,
-                                    std::map<const Atom *, uint64_t> &atomRva,
-                                    std::vector<uint64_t> &sectionRva,
-                                    uint64_t imageBaseAddress) {
+void AtomChunk::applyRelocationsARM(uint8_t *Buffer,
+                                    std::map<const Atom *, uint64_t> &AtomRVA,
+                                    std::vector<uint64_t> &SectionRVA,
+                                    uint64_t ImageBase) {
+  Buffer = Buffer + _fileOffset;
+  for (const auto *Layout : _atomLayouts) {
+    const DefinedAtom *Atom = cast<DefinedAtom>(Layout->_atom);
+    for (const Reference *R : *Atom) {
+      if (R->kindNamespace() != Reference::KindNamespace::COFF)
+        continue;
+
+      const auto AtomOffset = R->offsetInAtom();
+      const auto FileOffset = Layout->_fileOffset;
+      const auto TargetAddr = AtomRVA[R->target()];
+      auto RelocSite32 =
+          reinterpret_cast<ulittle32_t *>(Buffer + FileOffset + AtomOffset);
+
+      switch (R->kindValue()) {
+      default: llvm_unreachable("unsupported relocation type");
+      case llvm::COFF::IMAGE_REL_ARM_ADDR32:
+        *RelocSite32 = *RelocSite32 + TargetAddr + ImageBase;
+        break;
+      }
+    }
+  }
 }
 
 void AtomChunk::applyRelocationsX86(uint8_t *buffer,
diff --git a/test/pecoff/Inputs/armnt-addr32.obj.yaml b/test/pecoff/Inputs/armnt-addr32.obj.yaml
new file mode 100644
index 000000000..b13026308
--- /dev/null
+++ b/test/pecoff/Inputs/armnt-addr32.obj.yaml
@@ -0,0 +1,39 @@
+---
+header:
+  Machine:         IMAGE_FILE_MACHINE_ARMNT
+  Characteristics: [  ]
+sections:
+  - Name:            .rdata
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]
+    Alignment:       4
+    SectionData:     '0000000000000000'
+    Relocations:
+      - VirtualAddress:  4
+        SymbolName:      i
+        Type:            1
+symbols:
+  - Name:            .rdata
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          8
+      NumberOfRelocations: 1
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          1
+  - Name:            i
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            is
+    Value:           4
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+...
diff --git a/test/pecoff/Inputs/armnt-addr32.s b/test/pecoff/Inputs/armnt-addr32.s
new file mode 100644
index 000000000..c718e9518
--- /dev/null
+++ b/test/pecoff/Inputs/armnt-addr32.s
@@ -0,0 +1,18 @@
+
+@ static const int i = 0;
+@ const int * const is[] = { &i, };
+
+	.syntax unified
+	.thumb
+	.text
+
+	.section .rdata,"rd"
+	.align 2	# @i
+i:
+	.long 0		# 0x0
+
+	.global is	# @is
+	.align 2
+is:
+	.long i
+
diff --git a/test/pecoff/armnt-addr32.test b/test/pecoff/armnt-addr32.test
new file mode 100644
index 000000000..b586bebb2
--- /dev/null
+++ b/test/pecoff/armnt-addr32.test
@@ -0,0 +1,11 @@
+# RUN: yaml2obj -format coff -o %t.obj %p/Inputs/armnt-addr32.obj.yaml
+# RUN: llvm-objdump -s %t.obj | FileCheck %s -check-prefix BEFORE
+# RUN: lld -flavor link /entry:is /subsystem:console /out:%t.exe %t.obj
+# RUN: llvm-objdump -s %t.exe | FileCheck %s -check-prefix AFTER
+
+BEFORE: Contents of section .rdata:
+BEFORE:  0000 00000000 00000000
+
+AFTER: Contents of section .rdata:
+AFTER:  1000 00000000 00104000
+