Revert "revert r179735, it has no testcases, and doesn't really make sense."

This un-reverts r179735 and reverts commit r180574.

This fixes assertion failures for me locally and should fix the failures
on Windows reported widely on llvm-dev.  We should check if the bots
caught this and if so why not.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180722 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/IR/Attributes.h

@@ -307,7 +307,8 @@ public:
   unsigned getStackAlignment(unsigned Index) const;
 
   /// \brief Return the attributes at the index as a string.
-  std::string getAsString(unsigned Index, bool InAttrGrp = false) const;
+  std::string getAsString(unsigned Index, bool TargetIndependent = true,
+                          bool InAttrGrp = false) const;
 
   typedef ArrayRef<Attribute>::iterator iterator;
 

lib/IR/AsmWriter.cpp

@@ -33,6 +33,7 @@
 #include "llvm/IR/TypeFinder.h"
 #include "llvm/IR/ValueSymbolTable.h"
 #include "llvm/Support/CFG.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Dwarf.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -42,6 +43,12 @@
 #include <cctype>
 using namespace llvm;
 
+static cl::opt<bool>
+OldStyleAttrSyntax("enable-old-style-attr-syntax",
+    cl::desc("Output attributes on functions rather than in attribute groups"),
+    cl::Hidden,
+    cl::init(false));
+
 // Make virtual table appear in this compilation unit.
 AssemblyAnnotationWriter::~AssemblyAnnotationWriter() {}
 
@@ -1378,7 +1385,7 @@ void AssemblyWriter::printModule(const Module *M) {
     printFunction(I);
 
   // Output all attribute groups.
-  if (!Machine.as_empty()) {
+  if (!OldStyleAttrSyntax && !Machine.as_empty()) {
     Out << '\n';
     writeAllAttributeGroups();
   }
@@ -1606,24 +1613,9 @@ void AssemblyWriter::printFunction(const Function *F) {
     Out << "; Materializable\n";
 
   const AttributeSet &Attrs = F->getAttributes();
-  if (Attrs.hasAttributes(AttributeSet::FunctionIndex)) {
+  if (!OldStyleAttrSyntax && Attrs.hasAttributes(AttributeSet::FunctionIndex)) {
     AttributeSet AS = Attrs.getFnAttributes();
-    std::string AttrStr;
-
-    unsigned Idx = 0;
-    for (unsigned E = AS.getNumSlots(); Idx != E; ++Idx)
-      if (AS.getSlotIndex(Idx) == AttributeSet::FunctionIndex)
-        break;
-
-    for (AttributeSet::iterator I = AS.begin(Idx), E = AS.end(Idx);
-         I != E; ++I) {
-      Attribute Attr = *I;
-      if (!Attr.isStringAttribute()) {
-        if (!AttrStr.empty()) AttrStr += ' ';
-        AttrStr += Attr.getAsString();
-      }
-    }
-
+    std::string AttrStr = AS.getAsString(AttributeSet::FunctionIndex, false);
     if (!AttrStr.empty())
       Out << "; Function Attrs: " << AttrStr << '\n';
   }
@@ -1685,8 +1677,15 @@ void AssemblyWriter::printFunction(const Function *F) {
   Out << ')';
   if (F->hasUnnamedAddr())
     Out << " unnamed_addr";
-  if (Attrs.hasAttributes(AttributeSet::FunctionIndex))
-    Out << " #" << Machine.getAttributeGroupSlot(Attrs.getFnAttributes());
+  if (!OldStyleAttrSyntax) {
+    if (Attrs.hasAttributes(AttributeSet::FunctionIndex))
+      Out << " #" << Machine.getAttributeGroupSlot(Attrs.getFnAttributes());
+  } else {
+    AttributeSet AS = Attrs.getFnAttributes();
+    std::string AttrStr = AS.getAsString(AttributeSet::FunctionIndex, false);
+    if (!AttrStr.empty())
+      Out << ' ' << AttrStr;
+  }
   if (F->hasSection()) {
     Out << " section \"";
     PrintEscapedString(F->getSection(), Out);
@@ -2157,7 +2156,8 @@ void AssemblyWriter::writeAllAttributeGroups() {
   for (std::vector<std::pair<AttributeSet, unsigned> >::iterator
          I = asVec.begin(), E = asVec.end(); I != E; ++I)
     Out << "attributes #" << I->second << " = { "
-        << I->first.getAsString(AttributeSet::FunctionIndex, true) << " }\n";
+        << I->first.getAsString(AttributeSet::FunctionIndex, true, true)
+        << " }\n";
 }
 
 //===----------------------------------------------------------------------===//

lib/IR/AttributeImpl.h

@@ -178,7 +178,7 @@ public:
 
   unsigned getAlignment() const;
   unsigned getStackAlignment() const;
-  std::string getAsString(bool InAttrGrp) const;
+  std::string getAsString(bool TargetIndependent, bool InAttrGrp) const;
 
   typedef SmallVectorImpl<Attribute>::iterator       iterator;
   typedef SmallVectorImpl<Attribute>::const_iterator const_iterator;

lib/IR/Attributes.cpp

@@ -483,13 +483,16 @@ unsigned AttributeSetNode::getStackAlignment() const {
   return 0;
 }
 
-std::string AttributeSetNode::getAsString(bool InAttrGrp) const {
+std::string AttributeSetNode::getAsString(bool TargetIndependent,
+                                          bool InAttrGrp) const {
   std::string Str;
   for (SmallVectorImpl<Attribute>::const_iterator I = AttrList.begin(),
          E = AttrList.end(); I != E; ++I) {
-    if (I != AttrList.begin())
-      Str += ' ';
-    Str += I->getAsString(InAttrGrp);
+    if (TargetIndependent || !I->isStringAttribute()) {
+      if (I != AttrList.begin())
+        Str += ' ';
+      Str += I->getAsString(InAttrGrp);
+    }
   }
   return Str;
 }
@@ -845,10 +848,11 @@ unsigned AttributeSet::getStackAlignment(unsigned Index) const {
   return ASN ? ASN->getStackAlignment() : 0;
 }
 
-std::string AttributeSet::getAsString(unsigned Index,
+std::string AttributeSet::getAsString(unsigned Index, bool TargetIndependent,
                                       bool InAttrGrp) const {
   AttributeSetNode *ASN = getAttributes(Index);
-  return ASN ? ASN->getAsString(InAttrGrp) : std::string("");
+  return ASN ? ASN->getAsString(TargetIndependent, InAttrGrp) :
+    std::string("");
 }
 
 /// \brief The attributes for the specified index are returned.