From 45e6c195d7f48a9507edb4888db2964f1cd928d7 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Sat, 8 Jan 2011 16:42:36 +0000
Subject: First step in fixing PR8927:

Add a unnamed_addr bit to global variables and functions. This will be used
to indicate that the address is not significant and therefore the constant
or function can be merged with others.

If an optimization pass can show that an address is not used, it can set this.

Examples of things that can have this set by the FE are globals created to
hold string literals and C++ constructors.

Adding unnamed_addr to a non-const global should have no effect unless
an optimization can transform that global into a constant.

Aliases are not allowed to have unnamed_addr since I couldn't figure
out any use for it.

llvm-svn: 123063
---
 llvm/lib/Bitcode/Reader/BitcodeReader.cpp | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

(limited to 'llvm/lib/Bitcode/Reader/BitcodeReader.cpp')

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index e8b998e2a6c..7a71b267eaa 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1422,7 +1422,8 @@ bool BitcodeReader::ParseModule() {
       break;
     }
     // GLOBALVAR: [pointer type, isconst, initid,
-    //             linkage, alignment, section, visibility, threadlocal]
+    //             linkage, alignment, section, visibility, threadlocal,
+    //             unnamed_addr]
     case bitc::MODULE_CODE_GLOBALVAR: {
       if (Record.size() < 6)
         return Error("Invalid MODULE_CODE_GLOBALVAR record");
@@ -1449,6 +1450,10 @@ bool BitcodeReader::ParseModule() {
       if (Record.size() > 7)
         isThreadLocal = Record[7];
 
+      bool UnnamedAddr = false;
+      if (Record.size() > 8)
+        UnnamedAddr = Record[8];
+
       GlobalVariable *NewGV =
         new GlobalVariable(*TheModule, Ty, isConstant, Linkage, 0, "", 0,
                            isThreadLocal, AddressSpace);
@@ -1457,6 +1462,7 @@ bool BitcodeReader::ParseModule() {
         NewGV->setSection(Section);
       NewGV->setVisibility(Visibility);
       NewGV->setThreadLocal(isThreadLocal);
+      NewGV->setUnnamedAddr(UnnamedAddr);
 
       ValueList.push_back(NewGV);
 
@@ -1466,7 +1472,7 @@ bool BitcodeReader::ParseModule() {
       break;
     }
     // FUNCTION:  [type, callingconv, isproto, linkage, paramattr,
-    //             alignment, section, visibility, gc]
+    //             alignment, section, visibility, gc, unnamed_addr]
     case bitc::MODULE_CODE_FUNCTION: {
       if (Record.size() < 8)
         return Error("Invalid MODULE_CODE_FUNCTION record");
@@ -1499,6 +1505,10 @@ bool BitcodeReader::ParseModule() {
           return Error("Invalid GC ID");
         Func->setGC(GCTable[Record[8]-1].c_str());
       }
+      bool UnnamedAddr = false;
+      if (Record.size() > 9)
+        UnnamedAddr = Record[9];
+      Func->setUnnamedAddr(UnnamedAddr);
       ValueList.push_back(Func);
 
       // If this is a function with a body, remember the prototype we are
-- 
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