[llvm] r280357 - [IR] Properly handle escape characters in Attribute::getAsString()

[Honggyu Kim via llvm-commits]

Author: honggyu.kim
Date: Thu Sep  1 06:44:06 2016
New Revision: 280357

URL: http://llvm.org/viewvc/llvm-project?rev=280357&view=rev
Log:
[IR] Properly handle escape characters in Attribute::getAsString()

If an attribute name has special characters such as '\01', it is not
properly printed in LLVM assembly language format.  Since the format
expects the special characters are printed as it is, it has to contain
escape characters to make it printable.

Before:
  attributes #0 = { ... "counting-function"="^A__gnu_mcount_nc" ...

After:
  attributes #0 = { ... "counting-function"="\01__gnu_mcount_nc" ...

Reviewers: hfinkel, rengolin, rjmccall, compnerd

Subscribers: nemanjai, mcrosier, hans, shenhan, majnemer, llvm-commits

Differential Revision: https://reviews.llvm.org/D23792


Modified:
    llvm/trunk/include/llvm/ADT/StringExtras.h
    llvm/trunk/lib/IR/AsmWriter.cpp
    llvm/trunk/lib/IR/Attributes.cpp

Modified: llvm/trunk/include/llvm/ADT/StringExtras.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/StringExtras.h?rev=280357&r1=280356&r2=280357&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/StringExtras.h (original)
+++ llvm/trunk/include/llvm/ADT/StringExtras.h Thu Sep  1 06:44:06 2016
@@ -19,6 +19,7 @@
 #include <iterator>
 
 namespace llvm {
+class raw_ostream;
 template<typename T> class SmallVectorImpl;
 
 /// hexdigit - Return the hexadecimal character for the
@@ -150,6 +151,10 @@ static inline StringRef getOrdinalSuffix
   }
 }
 
+/// PrintEscapedString - Print each character of the specified string, escaping
+/// it if it is not printable or if it is an escape char.
+void PrintEscapedString(StringRef Name, raw_ostream &Out);
+
 template <typename IteratorT>
 inline std::string join_impl(IteratorT Begin, IteratorT End,
                              StringRef Separator, std::input_iterator_tag) {

Modified: llvm/trunk/lib/IR/AsmWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/AsmWriter.cpp?rev=280357&r1=280356&r2=280357&view=diff
==============================================================================
--- llvm/trunk/lib/IR/AsmWriter.cpp (original)
+++ llvm/trunk/lib/IR/AsmWriter.cpp Thu Sep  1 06:44:06 2016
@@ -337,9 +337,7 @@ static void PrintCallingConv(unsigned cc
   }
 }
 
-// PrintEscapedString - Print each character of the specified string, escaping
-// it if it is not printable or if it is an escape char.
-static void PrintEscapedString(StringRef Name, raw_ostream &Out) {
+void llvm::PrintEscapedString(StringRef Name, raw_ostream &Out) {
   for (unsigned i = 0, e = Name.size(); i != e; ++i) {
     unsigned char C = Name[i];
     if (isprint(C) && C != '\\' && C != '"')

Modified: llvm/trunk/lib/IR/Attributes.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Attributes.cpp?rev=280357&r1=280356&r2=280357&view=diff
==============================================================================
--- llvm/trunk/lib/IR/Attributes.cpp (original)
+++ llvm/trunk/lib/IR/Attributes.cpp Thu Sep  1 06:44:06 2016
@@ -381,10 +381,18 @@ std::string Attribute::getAsString(bool
     std::string Result;
     Result += (Twine('"') + getKindAsString() + Twine('"')).str();
 
-    StringRef Val = pImpl->getValueAsString();
-    if (Val.empty()) return Result;
+    std::string AttrVal = pImpl->getValueAsString();
+    if (AttrVal.empty()) return Result;
 
-    Result += ("=\"" + Val + Twine('"')).str();
+    // Since some attribute strings contain special characters that cannot be
+    // printable, those have to be escaped to make the attribute value printable
+    // as is.  e.g. "\01__gnu_mcount_nc"
+    {
+      raw_string_ostream OS(Result);
+      OS << "=\"";
+      PrintEscapedString(AttrVal, OS);
+      OS << "\"";
+    }
     return Result;
   }