From 933fcab2ad476809967695b9b11087c6b96d6b64 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Thu, 17 Nov 2016 23:16:39 +0000
Subject: [PATCH] Always compute sh_link for SHF_LINK_ORDER sections.

Since the output has a section table too, it is meaningful to compute
the sh_link. In a more practical note, the binutils' strip crashes if
sh_link is not set for SHT_ARM_EXIDX.

llvm-svn: 287280
---
 lld/ELF/OutputSections.cpp         | 20 +++++++-------------
 lld/test/ELF/arm-exidx-canunwind.s |  5 +++--
 lld/test/ELF/arm-exidx-link.s      | 24 ++++++++++++++++++++++++
 lld/test/ELF/arm-exidx-order.s     |  5 +++--
 lld/test/ELF/arm-exidx-output.s    |  5 +++--
 5 files changed, 40 insertions(+), 19 deletions(-)
 create mode 100644 lld/test/ELF/arm-exidx-link.s

diff --git a/lld/ELF/OutputSections.cpp b/lld/ELF/OutputSections.cpp
index f0b1ece..4bf9529 100644
--- a/lld/ELF/OutputSections.cpp
+++ b/lld/ELF/OutputSections.cpp
@@ -400,25 +400,19 @@ OutputSection<ELFT>::OutputSection(StringRef Name, uint32_t Type, uintX_t Flags)
 }
 
 template <class ELFT> void OutputSection<ELFT>::finalize() {
-  if (!Config->Relocatable) {
-    // SHF_LINK_ORDER only has meaning in relocatable objects
-    this->Flags &= ~SHF_LINK_ORDER;
-    return;
-  }
-
-  uint32_t Type = this->Type;
   if ((this->Flags & SHF_LINK_ORDER) && !this->Sections.empty()) {
-    // When doing a relocatable link we must preserve the link order
-    // dependency of sections with the SHF_LINK_ORDER flag. The dependency
-    // is indicated by the sh_link field. We need to translate the
-    // InputSection sh_link to the OutputSection sh_link, all InputSections
-    // in the OutputSection have the same dependency.
+    // We must preserve the link order dependency of sections with the
+    // SHF_LINK_ORDER flag. The dependency is indicated by the sh_link field. We
+    // need to translate the InputSection sh_link to the OutputSection sh_link,
+    // all InputSections in the OutputSection have the same dependency.
     if (auto *D = this->Sections.front()->getLinkOrderDep())
       this->Link = D->OutSec->SectionIndex;
   }
 
-  if (Type != SHT_RELA && Type != SHT_REL)
+  uint32_t Type = this->Type;
+  if (!Config->Relocatable || (Type != SHT_RELA && Type != SHT_REL))
     return;
+
   this->Link = In<ELFT>::SymTab->OutSec->SectionIndex;
   // sh_info for SHT_REL[A] sections should contain the section header index of
   // the section to which the relocation applies.
diff --git a/lld/test/ELF/arm-exidx-canunwind.s b/lld/test/ELF/arm-exidx-canunwind.s
index 7463480..0607ce3 100644
--- a/lld/test/ELF/arm-exidx-canunwind.s
+++ b/lld/test/ELF/arm-exidx-canunwind.s
@@ -76,8 +76,9 @@ _start:
 
 // CHECK-PT:          Name: .ARM.exidx
 // CHECK-PT-NEXT:     Type: SHT_ARM_EXIDX (0x70000001)
-// CHECK-PT-NEXT:     Flags [ (0x2)
-// CHECK-PT-NEXT:       SHF_ALLOC (0x2)
+// CHECK-PT-NEXT:     Flags [
+// CHECK-PT-NEXT:       SHF_ALLOC
+// CHECK-PT-NEXT:       SHF_LINK_ORDER
 // CHECK-PT-NEXT:     ]
 // CHECK-PT-NEXT:     Address: 0x100D4
 // CHECK-PT-NEXT:     Offset: 0xD4
diff --git a/lld/test/ELF/arm-exidx-link.s b/lld/test/ELF/arm-exidx-link.s
new file mode 100644
index 0000000..005bfff
--- /dev/null
+++ b/lld/test/ELF/arm-exidx-link.s
@@ -0,0 +1,24 @@
+// RUN: llvm-mc -filetype=obj -triple=armv7a-none-linux-gnueabi %s -o %t.o
+// RUN: ld.lld %t.o -o %t.so -shared
+// RUN: llvm-readobj -s %t.so | FileCheck %s
+
+// CHECK:      Name: .ARM.exidx
+// CHECK-NEXT: Type: SHT_ARM_EXIDX
+// CHECK-NEXT: Flags [
+// CHECK-NEXT:   SHF_ALLOC
+// CHECK-NEXT:   SHF_LINK_ORDER
+// CHECK-NEXT: ]
+// CHECK-NEXT: Address:
+// CHECK-NEXT: Offset:
+// CHECK-NEXT: Size:
+// CHECK-NEXT: Link: [[INDEX:.*]]
+
+// CHECK:      Index: [[INDEX]]
+// CHECK-NEXT: Name: .text
+
+
+        f:
+	.fnstart
+	bx	lr
+	.cantunwind
+	.fnend
diff --git a/lld/test/ELF/arm-exidx-order.s b/lld/test/ELF/arm-exidx-order.s
index 416c50f..5f6dbeb 100644
--- a/lld/test/ELF/arm-exidx-order.s
+++ b/lld/test/ELF/arm-exidx-order.s
@@ -103,8 +103,9 @@ f3:
 // the .ARM.exidx output section
 // CHECK-PT:          Name: .ARM.exidx
 // CHECK-PT-NEXT:     Type: SHT_ARM_EXIDX (0x70000001)
-// CHECK-PT-NEXT:     Flags [ (0x2)
-// CHECK-PT-NEXT:       SHF_ALLOC (0x2)
+// CHECK-PT-NEXT:     Flags [
+// CHECK-PT-NEXT:       SHF_ALLOC
+// CHECK-PT-NEXT:       SHF_LINK_ORDER
 // CHECK-PT-NEXT:     ]
 // CHECK-PT-NEXT:     Address: 0x100D4
 // CHECK-PT-NEXT:     Offset: 0xD4
diff --git a/lld/test/ELF/arm-exidx-output.s b/lld/test/ELF/arm-exidx-output.s
index 49bbb6c..dca43a3 100644
--- a/lld/test/ELF/arm-exidx-output.s
+++ b/lld/test/ELF/arm-exidx-output.s
@@ -35,8 +35,9 @@ f2:
 // CHECK:         Section {
 // CHECK:         Name: .ARM.exidx
 // CHECK-NEXT:    Type: SHT_ARM_EXIDX (0x70000001)
-// CHECK-NEXT:    Flags [ (0x2)
-// CHECK-NEXT:      SHF_ALLOC (0x2)
+// CHECK-NEXT:    Flags [
+// CHECK-NEXT:      SHF_ALLOC
+// CHECK-NEXT:      SHF_LINK_ORDER
 // CHECK-NEXT:    ]
 
 // CHECK-NOT:     Name: .ARM.exidx.text.f1
-- 
2.7.4