From 87f9577614a90f155dcdf59864d21dbc3f106469 Mon Sep 17 00:00:00 2001
From: Ian Lance Taylor <iant@google.com>
Date: Thu, 18 Oct 2007 17:46:23 +0000
Subject: [PATCH] Correctly handle alignment in merge sections.

---
 gold/merge.cc  | 10 +++++++---
 gold/merge.h   | 18 +++++++++++-------
 gold/output.cc | 19 ++++++++++---------
 gold/output.h  |  6 ++++--
 4 files changed, 32 insertions(+), 21 deletions(-)

diff --git a/gold/merge.cc b/gold/merge.cc
index f31b44e8055..b5c836f5f77 100644
--- a/gold/merge.cc
+++ b/gold/merge.cc
@@ -23,6 +23,7 @@
 #include "gold.h"
 
 #include <cstdlib>
+#include <algorithm>
 
 #include "merge.h"
 
@@ -161,10 +162,11 @@ void
 Output_merge_data::add_constant(const unsigned char* p)
 {
   uint64_t entsize = this->entsize();
-  if (this->len_ + entsize > this->alc_)
+  uint64_t addsize = std::max(entsize, this->addralign());
+  if (this->len_ + addsize > this->alc_)
     {
       if (this->alc_ == 0)
-	this->alc_ = 128 * entsize;
+	this->alc_ = 128 * addsize;
       else
 	this->alc_ *= 2;
       this->p_ = static_cast<unsigned char*>(realloc(this->p_, this->alc_));
@@ -173,7 +175,9 @@ Output_merge_data::add_constant(const unsigned char* p)
     }
 
   memcpy(this->p_ + this->len_, p, entsize);
-  this->len_ += entsize;
+  if (addsize > entsize)
+    memset(this->p_ + this->len_ + entsize, 0, addsize - entsize);
+  this->len_ += addsize;
 }
 
 // Add the input section SHNDX in OBJECT to a merged output section
diff --git a/gold/merge.h b/gold/merge.h
index ab382a11659..cc554f26f4d 100644
--- a/gold/merge.h
+++ b/gold/merge.h
@@ -37,8 +37,8 @@ namespace gold
 class Output_merge_base : public Output_section_data
 {
  public:
-  Output_merge_base(uint64_t entsize)
-    : Output_section_data(1), merge_map_(), entsize_(entsize)
+  Output_merge_base(uint64_t entsize, uint64_t addralign)
+    : Output_section_data(addralign), merge_map_(), entsize_(entsize)
   { }
 
   // Return the output address for an input address.
@@ -90,8 +90,8 @@ class Output_merge_base : public Output_section_data
 class Output_merge_data : public Output_merge_base
 {
  public:
-  Output_merge_data(uint64_t entsize)
-    : Output_merge_base(entsize), p_(NULL), len_(0), alc_(0),
+  Output_merge_data(uint64_t entsize, uint64_t addralign)
+    : Output_merge_base(entsize, addralign), p_(NULL), len_(0), alc_(0),
       hashtable_(128, Merge_data_hash(this), Merge_data_eq(this))
   { }
 
@@ -188,9 +188,13 @@ template<typename Char_type>
 class Output_merge_string : public Output_merge_base
 {
  public:
-  Output_merge_string()
-    : Output_merge_base(sizeof(Char_type)), stringpool_(), merged_strings_()
-  { this->stringpool_.set_no_zero_null(); }
+  Output_merge_string(uint64_t addralign)
+    : Output_merge_base(sizeof(Char_type), addralign), stringpool_(),
+      merged_strings_()
+  {
+    gold_assert(addralign <= sizeof(Char_type));
+    this->stringpool_.set_no_zero_null();
+  }
 
   // Add an input section.
   bool
diff --git a/gold/output.cc b/gold/output.cc
index 9aaa7e97410..acba77ce459 100644
--- a/gold/output.cc
+++ b/gold/output.cc
@@ -1137,17 +1137,18 @@ Output_section::add_merge_input_section(Relobj* object, unsigned int shndx,
 					uint64_t flags, uint64_t entsize,
 					uint64_t addralign)
 {
-  // We only merge constants if the alignment is not more than the
-  // entry size.  This could be handled, but it's unusual.
-  if (addralign > entsize)
+  bool is_string = (flags & elfcpp::SHF_STRINGS) != 0;
+
+  // We only merge strings if the alignment is not more than the
+  // character size.  This could be handled, but it's unusual.
+  if (is_string && addralign > entsize)
     return false;
 
-  bool is_string = (flags & elfcpp::SHF_STRINGS) != 0;
   Input_section_list::iterator p;
   for (p = this->input_sections_.begin();
        p != this->input_sections_.end();
        ++p)
-    if (p->is_merge_section(is_string, entsize))
+    if (p->is_merge_section(is_string, entsize, addralign))
       break;
 
   // We handle the actual constant merging in Output_merge_data or
@@ -1158,13 +1159,13 @@ Output_section::add_merge_input_section(Relobj* object, unsigned int shndx,
     {
       Output_section_data* posd;
       if (!is_string)
-	posd = new Output_merge_data(entsize);
+	posd = new Output_merge_data(entsize, addralign);
       else if (entsize == 1)
-	posd = new Output_merge_string<char>();
+	posd = new Output_merge_string<char>(addralign);
       else if (entsize == 2)
-	posd = new Output_merge_string<uint16_t>();
+	posd = new Output_merge_string<uint16_t>(addralign);
       else if (entsize == 4)
-	posd = new Output_merge_string<uint32_t>();
+	posd = new Output_merge_string<uint32_t>(addralign);
       else
 	return false;
 
diff --git a/gold/output.h b/gold/output.h
index c525a329c03..a615a71150e 100644
--- a/gold/output.h
+++ b/gold/output.h
@@ -1436,12 +1436,14 @@ class Output_section : public Output_data
     // Return whether this is a merge section which matches the
     // parameters.
     bool
-    is_merge_section(bool is_string, uint64_t entsize) const
+    is_merge_section(bool is_string, uint64_t entsize,
+                     uint64_t addralign) const
     {
       return (this->shndx_ == (is_string
 			       ? MERGE_STRING_SECTION_CODE
 			       : MERGE_DATA_SECTION_CODE)
-	      && this->u1_.entsize == entsize);
+	      && this->u1_.entsize == entsize
+              && this->addralign() == addralign);
     }
 
     // Set the output section.
-- 
2.30.2