[PATCH] D41551: [ELF] - Allow relocation to a weak undefined symbol when -z notext is given.

[George Rimar via Phabricator via llvm-commits]

grimar updated this revision to Diff 128095.
grimar added a comment.

- Updated comment.


https://reviews.llvm.org/D41551

Files:
  ELF/Relocations.cpp
  test/ELF/znotext-weak-undef.s


Index: test/ELF/znotext-weak-undef.s
===================================================================
--- test/ELF/znotext-weak-undef.s
+++ test/ELF/znotext-weak-undef.s
@@ -0,0 +1,14 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: ld.lld -z notext -shared %t.o -o %t
+# RUN: llvm-readobj -r %t | FileCheck %s
+
+# CHECK:      Relocations [
+# CHECK-NEXT: ]
+
+.text
+.global foo
+.weak foo
+
+_start:
+mov $foo,%eax
Index: ELF/Relocations.cpp
===================================================================
--- ELF/Relocations.cpp
+++ ELF/Relocations.cpp
@@ -589,33 +589,33 @@
   if (S.Flags & SHF_WRITE)
     return Expr;
 
-  // Or, if we are allowed to create dynamic relocations against
-  // read-only sections (i.e. when "-z notext" is given),
-  // we can create a dynamic relocation as we want, too.
-  if (!Config->ZText) {
-    // We use PLT for relocations that may overflow in runtime,
-    // see comment for getPltExpr().
-    if (Sym.isFunc() && !Target->isPicRel(Type))
-      return getPltExpr(Sym, Expr, IsConstant);
-    return Expr;
-  }
-
   // If a relocation can be applied at link-time, we don't need to
   // create a dynamic relocation in the first place.
   if (IsConstant)
     return Expr;
 
-  // If we got here we know that this relocation would require the dynamic
-  // linker to write a value to read only memory.
-
   // If the relocation is to a weak undef, give up on it and produce a
   // non preemptible 0.
   if (Sym.isUndefWeak()) {
     Sym.IsPreemptible = false;
     IsConstant = true;
     return Expr;
   }
 
+  // If we are allowed to create dynamic relocations against
+  // read-only sections (i.e. when "-z notext" is given),
+  // we can create a dynamic relocation as we want.
+  if (!Config->ZText) {
+    // We use PLT for relocations that may overflow in runtime,
+    // see comment for getPltExpr().
+    if (Sym.isFunc() && !Target->isPicRel(Type))
+      return getPltExpr(Sym, Expr, IsConstant);
+    return Expr;
+  }
+
+  // If we got here we know that this relocation would require the dynamic
+  // linker to write a value to read only memory.
+
   // We can hack around it if we are producing an executable and
   // the refered symbol can be preemepted to refer to the executable.
   if (Config->Shared || (Config->Pic && !isRelExpr(Expr))) {


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