commit f3d7904d20120fb6e4b33cd391b916ca6701e03e
author Javed Absar <javed.absar@arm.com> Thu May 11 12:28:08 2017 +0000
committer Javed Absar <javed.absar@arm.com> Thu May 11 12:28:08 2017 +0000
tree 45229dfdd32c355e31e095a197b3bb53d84f2d85
parent a44fc83d9fa3bcbe45b1ebb2f0aca2a86dba181d

[IR] Allow attributes with global variables

This patch extends llvm-ir to allow attributes to be set on global variables.
An RFC was sent out earlier by my colleague James Molloy: http://lists.llvm.org/pipermail/cfe-dev/2017-March/053100.html
A key part of that proposal was to extend LLVM-IR to carry attributes on global variables.
This generic feature could be useful for multiple purposes.
In our present context, it would be useful to carry user specified sections for bss/rodata/data.

Reviewed by: Jonathan Roelofs, Reid Kleckner
Differential Revision: https://reviews.llvm.org/D32009

llvm-svn: 302794

llvm/lib/Bitcode/Writer/BitcodeWriter.cpp

diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 1b8d81a..1f8b503 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1109,7 +1109,7 @@
     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
     //             linkage, alignment, section, visibility, threadlocal,
     //             unnamed_addr, externally_initialized, dllstorageclass,
-    //             comdat]
+    //             comdat, attributes]
     Vals.push_back(StrtabBuilder.add(GV.getName()));
     Vals.push_back(GV.getName().size());
     Vals.push_back(VE.getTypeID(GV.getValueType()));
@@ -1124,13 +1124,17 @@
         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
         GV.isExternallyInitialized() ||
         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
-        GV.hasComdat()) {
+        GV.hasComdat() ||
+        GV.hasAttributes()) {
       Vals.push_back(getEncodedVisibility(GV));
       Vals.push_back(getEncodedThreadLocalMode(GV));
       Vals.push_back(getEncodedUnnamedAddr(GV));
       Vals.push_back(GV.isExternallyInitialized());
       Vals.push_back(getEncodedDLLStorageClass(GV));
       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
+
+      auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
+      Vals.push_back(VE.getAttributeListID(AL));
     } else {
       AbbrevToUse = SimpleGVarAbbrev;
     }

llvm/lib/Bitcode/Writer/ValueEnumerator.cpp

diff --git a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
index 8611507..fd76400 100644
--- a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -314,10 +314,13 @@
   // Remember what is the cutoff between globalvalue's and other constants.
   unsigned FirstConstant = Values.size();
 
-  // Enumerate the global variable initializers.
-  for (const GlobalVariable &GV : M.globals())
+  // Enumerate the global variable initializers and attributes.
+  for (const GlobalVariable &GV : M.globals()) {
     if (GV.hasInitializer())
       EnumerateValue(GV.getInitializer());
+    if (GV.hasAttributes())
+      EnumerateAttributes(GV.getAttributesAsList(AttributeList::FunctionIndex));
+  }
 
   // Enumerate the aliasees.
   for (const GlobalAlias &GA : M.aliases())