[LLD][COFF] Implement ARM64X relocations for the exception table (#123723)

Author: cjacek

lld/COFF/Chunks.cpp

@@ -1167,7 +1167,7 @@ uint32_t ImportThunkChunkARM64EC::extendRanges() {
 }
 
 uint64_t Arm64XRelocVal::get() const {
-  return (sym ? sym->getRVA() : 0) + value;
+  return (sym ? sym->getRVA() : 0) + (chunk ? chunk->getRVA() : 0) + value;
 }
 
 size_t Arm64XDynamicRelocEntry::getSize() const {
@@ -1230,6 +1230,17 @@ void DynamicRelocsChunk::finalize() {
   size = alignTo(size, sizeof(uint32_t));
 }
 
+// Set the reloc value. The reloc entry must be allocated beforehand.
+void DynamicRelocsChunk::set(uint32_t rva, Arm64XRelocVal value) {
+  auto entry =
+      llvm::find_if(arm64xRelocs, [rva](const Arm64XDynamicRelocEntry &e) {
+        return e.offset.get() == rva;
+      });
+  assert(entry != arm64xRelocs.end());
+  assert(!entry->value.get());
+  entry->value = value;
+}
+
 void DynamicRelocsChunk::writeTo(uint8_t *buf) const {
   auto table = reinterpret_cast<coff_dynamic_reloc_table *>(buf);
   table->Version = 1;

lld/COFF/Chunks.h

@@ -840,10 +840,13 @@ class Arm64XRelocVal {
 public:
   Arm64XRelocVal(uint64_t value = 0) : value(value) {}
   Arm64XRelocVal(Defined *sym, int32_t offset = 0) : sym(sym), value(offset) {}
+  Arm64XRelocVal(Chunk *chunk, int32_t offset = 0)
+      : chunk(chunk), value(offset) {}
   uint64_t get() const;
 
 private:
   Defined *sym = nullptr;
+  Chunk *chunk = nullptr;
   uint64_t value;
 };
 
@@ -874,10 +877,12 @@ class DynamicRelocsChunk : public NonSectionChunk {
   void finalize();
 
   void add(llvm::COFF::Arm64XFixupType type, uint8_t size,
-           Arm64XRelocVal offset, Arm64XRelocVal value) {
+           Arm64XRelocVal offset, Arm64XRelocVal value = Arm64XRelocVal()) {
     arm64xRelocs.emplace_back(type, size, offset, value);
   }
 
+  void set(uint32_t rva, Arm64XRelocVal value);
+
 private:
   std::vector<Arm64XDynamicRelocEntry> arm64xRelocs;
   size_t size;

lld/COFF/Writer.cpp

@@ -2392,6 +2392,13 @@ void Writer::setECSymbols() {
       symtab->findUnderscore("__arm64x_native_entrypoint")
           ->replaceKeepingName(altEntrySym, sizeof(SymbolUnion));
     }
+
+    if (hybridPdata.first)
+      ctx.dynamicRelocs->set(
+          dataDirOffset64 + EXCEPTION_TABLE * sizeof(data_directory) +
+              offsetof(data_directory, Size),
+          hybridPdata.last->getRVA() - hybridPdata.first->getRVA() +
+              hybridPdata.last->getSize());
   }
 }
 
@@ -2644,6 +2651,19 @@ void Writer::createDynamicRelocs() {
       Warn(ctx) << "'__chpe_metadata' is missing for ARM64X target";
   }
 
+  if (pdata.first != hybridPdata.first) {
+    ctx.dynamicRelocs->add(IMAGE_DVRT_ARM64X_FIXUP_TYPE_VALUE, sizeof(uint32_t),
+                           dataDirOffset64 +
+                               EXCEPTION_TABLE * sizeof(data_directory) +
+                               offsetof(data_directory, RelativeVirtualAddress),
+                           hybridPdata.first);
+    // The Size value is assigned after addresses are finalized.
+    ctx.dynamicRelocs->add(IMAGE_DVRT_ARM64X_FIXUP_TYPE_VALUE, sizeof(uint32_t),
+                           dataDirOffset64 +
+                               EXCEPTION_TABLE * sizeof(data_directory) +
+                               offsetof(data_directory, Size));
+  }
+
   // Set the hybrid load config to the EC load config.
   ctx.dynamicRelocs->add(IMAGE_DVRT_ARM64X_FIXUP_TYPE_VALUE, sizeof(uint32_t),
                          dataDirOffset64 +

lld/test/COFF/pdata-arm64ec.test

@@ -6,6 +6,7 @@ Test handlign of hybrid .pdata section on ARM64EC target.
 RUN: llvm-mc -filetype=obj -triple=arm64-windows arm64-func-sym.s -o arm64-func-sym.obj
 RUN: llvm-mc -filetype=obj -triple=arm64ec-windows arm64ec-func-sym.s -o arm64ec-func-sym.obj
 RUN: llvm-mc -filetype=obj -triple=x86_64-windows x86_64-func-sym.s -o x86_64-func-sym.obj
+RUN: llvm-mc -filetype=obj -triple=aarch64-windows %S/Inputs/loadconfig-arm64.s -o loadconfig-arm64.obj
 RUN: llvm-mc -filetype=obj -triple=arm64ec-windows %p/Inputs/loadconfig-arm64ec.s -o loadconfig-arm64ec.obj
 
 Only arm64ec code:
@@ -55,11 +56,21 @@ DATA3: 180005000 00100000 11000001 00200000 0e200000
 Mixed arm64x code:
 
 RUN: lld-link -out:test4.dll -machine:arm64x arm64-func-sym.obj arm64ec-func-sym.obj \
-RUN:          x86_64-func-sym.obj loadconfig-arm64ec.obj -dll -noentry
+RUN:          x86_64-func-sym.obj loadconfig-arm64.obj loadconfig-arm64ec.obj -dll -noentry
 
 RUN: llvm-readobj --headers test4.dll | FileCheck -check-prefix=DIR3 %s
-DIR3:      ExceptionTableRVA: 0x6000
-DIR3-NEXT: ExceptionTableSize: 0x10
+DIR3:      ImageOptionalHeader {
+DIR3:        DataDirectory {
+DIR3:          ExceptionTableRVA: 0x6000
+DIR3-NEXT:     ExceptionTableSize: 0x10
+DIR3:        }
+DIR3:      }
+DIR3:      HybridObject {
+DIR3:        ImageOptionalHeader {
+DIR3:          ExceptionTableRVA: 0x6010
+DIR3-NEXT:     ExceptionTableSize: 0xC
+DIR3:        }
+DIR3:      }
 
 RUN: llvm-objdump -s --section=.pdata test4.dll | FileCheck -check-prefix=DATA4 %s
 DATA4: 180006000 00100000 11000001 00200000 11000001  ......... ......
@@ -74,12 +85,12 @@ RUN: llvm-readobj --headers test5.dll | FileCheck -check-prefix=DIR2 %s
 RUN: llvm-objdump -s --section=.pdata test5.dll | FileCheck -check-prefix=DATA3 %s
 
 RUN: lld-link -out:test6.dll -machine:arm64x arm64ec-func-sym.obj x86_64-func-sym.obj \
-RUN:          arm64-func-sym.obj loadconfig-arm64ec.obj -dll -noentry
+RUN:          arm64-func-sym.obj loadconfig-arm64.obj loadconfig-arm64ec.obj -dll -noentry
 RUN: llvm-readobj --headers test6.dll | FileCheck -check-prefix=DIR3 %s
 RUN: llvm-objdump -s --section=.pdata test6.dll | FileCheck -check-prefix=DATA4 %s
 
 RUN: lld-link -out:test7.dll -machine:arm64x x86_64-func-sym.obj arm64ec-func-sym.obj \
-RUN:          arm64-func-sym.obj loadconfig-arm64ec.obj -dll -noentry
+RUN:          arm64-func-sym.obj loadconfig-arm64.obj loadconfig-arm64ec.obj -dll -noentry
 RUN: llvm-readobj --headers test7.dll | FileCheck -check-prefix=DIR3 %s
 RUN: llvm-objdump -s --section=.pdata test7.dll | FileCheck -check-prefix=DATA4 %s