[RelLookupTableConverter] Drop unnamed_addr to avoid generating GOTPCREL relocations

Author: dianqk

llvm/lib/Transforms/Utils/RelLookupTableConverter.cpp

@@ -110,6 +110,11 @@ static GlobalVariable *createRelLookupTable(Function &Func,
 
   for (Use &Operand : LookupTableArr->operands()) {
     Constant *Element = cast<Constant>(Operand);
+    // Drop unnamed_addr to avoid matching pattern in
+    // `handleIndirectSymViaGOTPCRel`, which creates GOTPCREL relocations not
+    // supported by the GNU linker and LLD versions below 18 on aarch64.
+    if (auto *GlobalElement = dyn_cast<GlobalValue>(Element))
+      GlobalElement->setUnnamedAddr(GlobalValue::UnnamedAddr::None);
     Type *IntPtrTy = M.getDataLayout().getIntPtrType(M.getContext());
     Constant *Base = llvm::ConstantExpr::getPtrToInt(RelLookupTable, IntPtrTy);
     Constant *Target = llvm::ConstantExpr::getPtrToInt(Element, IntPtrTy);

llvm/test/Transforms/RelLookupTableConverter/unnamed_addr.ll

@@ -18,32 +18,32 @@
 @load_relative_2.table = private unnamed_addr constant [4 x ptr] [ptr @y3, ptr @y2, ptr @y1, ptr @y0]
 
 ;.
-; x86_64: @a0 = private unnamed_addr constant i32 0
-; x86_64: @a1 = private unnamed_addr constant i32 1
-; x86_64: @a2 = private unnamed_addr constant i32 2
+; x86_64: @a0 = private constant i32 0
+; x86_64: @a1 = private constant i32 1
+; x86_64: @a2 = private constant i32 2
 ; x86_64: @load_relative_1.table.rel = private unnamed_addr constant [3 x i32] [i32 trunc (i64 sub (i64 ptrtoint (ptr @a0 to i64), i64 ptrtoint (ptr @load_relative_1.table.rel to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr @a1 to i64), i64 ptrtoint (ptr @load_relative_1.table.rel to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr @a2 to i64), i64 ptrtoint (ptr @load_relative_1.table.rel to i64)) to i32)], align 4
 ; x86_64: @x0 = internal unnamed_addr constant i64 0
 ; x86_64: @x1 = internal unnamed_addr constant i64 1
 ; x86_64: @x2 = internal unnamed_addr constant i64 2
 ; x86_64: @x3 = internal unnamed_addr constant i64 3
-; x86_64: @y0 = internal unnamed_addr constant ptr @x3
-; x86_64: @y1 = internal unnamed_addr constant ptr @x2
-; x86_64: @y2 = internal unnamed_addr constant ptr @x1
-; x86_64: @y3 = internal unnamed_addr constant ptr @x0
+; x86_64: @y0 = internal constant ptr @x3
+; x86_64: @y1 = internal constant ptr @x2
+; x86_64: @y2 = internal constant ptr @x1
+; x86_64: @y3 = internal constant ptr @x0
 ; x86_64: @load_relative_2.table.rel = private unnamed_addr constant [4 x i32] [i32 trunc (i64 sub (i64 ptrtoint (ptr @y3 to i64), i64 ptrtoint (ptr @load_relative_2.table.rel to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr @y2 to i64), i64 ptrtoint (ptr @load_relative_2.table.rel to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr @y1 to i64), i64 ptrtoint (ptr @load_relative_2.table.rel to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr @y0 to i64), i64 ptrtoint (ptr @load_relative_2.table.rel to i64)) to i32)], align 4
 ;.
-; aarch64: @a0 = private unnamed_addr constant i32 0
-; aarch64: @a1 = private unnamed_addr constant i32 1
-; aarch64: @a2 = private unnamed_addr constant i32 2
+; aarch64: @a0 = private constant i32 0
+; aarch64: @a1 = private constant i32 1
+; aarch64: @a2 = private constant i32 2
 ; aarch64: @load_relative_1.table.rel = private unnamed_addr constant [3 x i32] [i32 trunc (i64 sub (i64 ptrtoint (ptr @a0 to i64), i64 ptrtoint (ptr @load_relative_1.table.rel to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr @a1 to i64), i64 ptrtoint (ptr @load_relative_1.table.rel to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr @a2 to i64), i64 ptrtoint (ptr @load_relative_1.table.rel to i64)) to i32)], align 4
 ; aarch64: @x0 = internal unnamed_addr constant i64 0
 ; aarch64: @x1 = internal unnamed_addr constant i64 1
 ; aarch64: @x2 = internal unnamed_addr constant i64 2
 ; aarch64: @x3 = internal unnamed_addr constant i64 3
-; aarch64: @y0 = internal unnamed_addr constant ptr @x3
-; aarch64: @y1 = internal unnamed_addr constant ptr @x2
-; aarch64: @y2 = internal unnamed_addr constant ptr @x1
-; aarch64: @y3 = internal unnamed_addr constant ptr @x0
+; aarch64: @y0 = internal constant ptr @x3
+; aarch64: @y1 = internal constant ptr @x2
+; aarch64: @y2 = internal constant ptr @x1
+; aarch64: @y3 = internal constant ptr @x0
 ; aarch64: @load_relative_2.table.rel = private unnamed_addr constant [4 x i32] [i32 trunc (i64 sub (i64 ptrtoint (ptr @y3 to i64), i64 ptrtoint (ptr @load_relative_2.table.rel to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr @y2 to i64), i64 ptrtoint (ptr @load_relative_2.table.rel to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr @y1 to i64), i64 ptrtoint (ptr @load_relative_2.table.rel to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr @y0 to i64), i64 ptrtoint (ptr @load_relative_2.table.rel to i64)) to i32)], align 4
 ;.
 define ptr @load_relative_1(i64 %offset) {