Fix --filetype=iasm non-pc-rel fixup offsets (double counted).

src/IceAssembler.cpp

@@ -132,6 +132,10 @@ void Assembler::emitIASBytes(GlobalContext *Ctx) const {
       Str << "\n";
     }
     Str << "\t.long ";
+    // For PCRel fixups, we write the pc-offset from a symbol into the Buffer
+    // (e.g., -4), but we don't represent that in the fixup's offset.
+    // Otherwise the fixup holds the true offset, and so does the Buffer.
+    // Just load the offset from the buffer.
     NextFixup->emit(Ctx, Buffer.load<RelocOffsetT>(NextFixupLoc));
     if (fixupIsPCRel(NextFixup->kind()))
       Str << " - .";

src/IceELFSection.h

@@ -362,6 +362,8 @@ void ELFRelocationSection::writeData(const GlobalContext &Ctx, ELFStreamer &Str,
       llvm::report_fatal_error("Missing symbol mentioned in reloc");
 
     if (IsELF64) {
+      llvm_unreachable(
+          "Not tested -- check that Fixup.offset() is correct even for pc-rel");
       Elf64_Rela Rela;
       Rela.r_offset = Fixup.position();
       Rela.setSymbolAndType(Symbol->getNumber(), Fixup.kind());

src/IceFixups.cpp

@@ -48,7 +48,8 @@ IceString AssemblerFixup::symbol(const GlobalContext *Ctx) const {
   return Str.str();
 }
 
-void AssemblerFixup::emit(GlobalContext *Ctx, RelocOffsetT BaseOffset) const {
+void AssemblerFixup::emit(GlobalContext *Ctx,
+                          RelocOffsetT OverrideOffset) const {
   if (!BuildDefs::dump())
     return;
   Ostream &Str = Ctx->getStrEmit();
@@ -56,7 +57,7 @@ void AssemblerFixup::emit(GlobalContext *Ctx, RelocOffsetT BaseOffset) const {
     Str << "__Sz_AbsoluteZero";
   else
     Str << symbol(Ctx);
-  RelocOffsetT Offset = offset() + BaseOffset;
+  RelocOffsetT Offset = OverrideOffset;
   if (Offset)
     Str << " + " << Offset;
 }

src/IceFixups.h

@@ -45,7 +45,7 @@ public:
 
   void set_value(const Constant *Value) { value_ = Value; }
 
-  void emit(GlobalContext *Ctx, RelocOffsetT BaseOffset) const;
+  void emit(GlobalContext *Ctx, RelocOffsetT OverrideOffset) const;
 
 private:
   intptr_t position_ = 0;

tests_lit/llvm2ice_tests/ias-data-reloc.ll

+; Tests the integrated assembler for instructions with a reloc + offset.
+
+; RUN: %if --need=target_X8632 --need=allow_dump \
+; RUN:   --command %p2i --target x8632 -i %s --args -O2 \
+; RUN:   | %if --need=target_X8632 --need=allow_dump --command FileCheck %s
+
+@p_global_char = internal global [8 x i8] zeroinitializer, align 8
+
+define internal void @reloc_in_global(i64 %x) {
+entry:
+  %p_global_char.bc = bitcast [8 x i8]* @p_global_char to i64*
+  ; This 64-bit load is split into an i32 store to [p_global_char]
+  ; and an i32 store to [p_global_char + 4] on 32-bit architectures.
+  store i64 %x, i64* %p_global_char.bc, align 1
+  ret void
+}
+; CHECK-LABEL: reloc_in_global
+; CHECK: .long p_global_char + 4