From c65ae14766f0802fd33d4fa9c1b2a41a2ad1c412 Mon Sep 17 00:00:00 2001
From: Zaara Syeda <syzaara@ca.ibm.com>
Date: Mon, 26 Mar 2018 17:50:52 +0000
Subject: [PATCH] [ELF] GotSection increment NumEntries when Target saves
 GlobalOffsetTable in the .got

When the target saves ElfSym::GlobalOffsetTable in the .got rather than
.got.plt, Target->GotHeaderEntriesNum states the number of extra entries
required in the .got. Rather than having to add Target->GotHeaderEntriesNum to
NumEntries in every function which refers to NumEntries, this patch changes the
initial value of NumEntries in the constructor.

Differential Revision: https://reviews.llvm.org/D44744

llvm-svn: 328559
---
 lld/ELF/SyntheticSections.cpp    | 14 +++++++++++---
 lld/test/ELF/ppc64_entry_point.s |  5 ++++-
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/lld/ELF/SyntheticSections.cpp b/lld/ELF/SyntheticSections.cpp
index c55b4fe8626b..fb5b3238bccc 100644
--- a/lld/ELF/SyntheticSections.cpp
+++ b/lld/ELF/SyntheticSections.cpp
@@ -587,10 +587,18 @@ void EhFrameSection::writeTo(uint8_t *Buf) {
 
 GotSection::GotSection()
     : SyntheticSection(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
-                       Target->GotEntrySize, ".got") {}
+                       Target->GotEntrySize, ".got") {
+  // PPC64 saves the ElfSym::GlobalOffsetTable .TOC. as the first entry in the
+  // .got. If there are no references to .TOC. in the symbol table,
+  // ElfSym::GlobalOffsetTable will not be defined and we won't need to save
+  // .TOC. in the .got. When it is defined, we increase NumEntries by the number
+  // of entries used to emit ElfSym::GlobalOffsetTable.
+  if (ElfSym::GlobalOffsetTable && !Target->GotBaseSymInGotPlt)
+    NumEntries += Target->GotHeaderEntriesNum;
+}
 
 void GotSection::addEntry(Symbol &Sym) {
-  Sym.GotIndex = Target->GotHeaderEntriesNum + NumEntries;
+  Sym.GotIndex = NumEntries;
   ++NumEntries;
 }
 
@@ -622,7 +630,7 @@ uint64_t GotSection::getGlobalDynOffset(const Symbol &B) const {
 }
 
 void GotSection::finalizeContents() {
-  Size = (NumEntries + Target->GotHeaderEntriesNum) * Config->Wordsize;
+  Size = NumEntries * Config->Wordsize;
 }
 
 bool GotSection::empty() const {
diff --git a/lld/test/ELF/ppc64_entry_point.s b/lld/test/ELF/ppc64_entry_point.s
index 733c4cc32bc5..b3bd5ec5a923 100644
--- a/lld/test/ELF/ppc64_entry_point.s
+++ b/lld/test/ELF/ppc64_entry_point.s
@@ -1,7 +1,7 @@
 # REQUIRES: ppc
 # RUN: llvm-mc -filetype=obj -triple=powerpc64le-unknown-linux %s -o %t
 # RUN: ld.lld %t -o %t2
-# RUN: llvm-objdump -d %t2 | FileCheck %s
+# RUN: llvm-objdump -D %t2 | FileCheck %s
 
 .text
 .abiversion 2
@@ -31,3 +31,6 @@ _start:
 // CHECK-NEXT: 10010004:       00 00 84 38     addi 4, 4, 0
 // CHECK-NEXT: 10010008:       02 00 a0 3c     lis 5, 2
 // CHECK-NEXT: 1001000c:       00 80 a5 38     addi 5, 5, -32768
+// CHECK: Disassembly of section .got:
+// CHECK-NEXT: .got:
+// CHECK-NEXT: 10020000:       00 80 02 10