[ADT] Replace std::isprint by llvm::isPrint.

The standard library functions ::isprint/std::isprint have platform-
and locale-dependent behavior which makes LLVM's output less
predictable. In particular, regression tests my fail depending on the
implementation of these functions.

Implement llvm::isPrint in StringExtras.h with a standard behavior and
replace all uses of ::isprint/std::isprint by a call it llvm::isPrint.
The function is inlined and does not look up language settings so it
should perform better than the standard library's version.

Such a replacement has already been done for isdigit, isalpha, isxdigit
in r314883. gtest does the same in gtest-printers.cc using the following
justification:

    // Returns true if c is a printable ASCII character.  We test the
    // value of c directly instead of calling isprint(), which is buggy on
    // Windows Mobile.
    inline bool IsPrintableAscii(wchar_t c) {
      return 0x20 <= c && c <= 0x7E;
    }

Similar issues have also been encountered by Julia:
https://github.com/JuliaLang/julia/issues/7416

I noticed the problem myself when on Windows isprint('\t') started to
evaluate to true (see https://stackoverflow.com/questions/51435249) and
thus caused several unit tests to fail. The result of isprint doesn't
seem to be well-defined even for ASCII characters. Therefore I suggest
to replace isprint by a platform-independent version.

Differential Revision: https://reviews.llvm.org/D49680

llvm-svn: 338034

5 files changed, 6 insertions, 6 deletions

diff --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
index 1429f647b61..88154bd7b25 100644
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -815,7 +815,7 @@ static void PrintQuotedString(StringRef Data, raw_ostream &OS) {
       continue;
     }
 
-    if (isprint((unsigned char)C)) {
+    if (isPrint((unsigned char)C)) {
       OS << (char)C;
       continue;
     }
diff --git a/llvm/lib/ProfileData/InstrProfReader.cpp b/llvm/lib/ProfileData/InstrProfReader.cpp
index 64f98ad0051..3b704158a5c 100644
--- a/llvm/lib/ProfileData/InstrProfReader.cpp
+++ b/llvm/lib/ProfileData/InstrProfReader.cpp
@@ -129,7 +129,7 @@ bool TextInstrProfReader::hasFormat(const MemoryBuffer &Buffer) {
   StringRef buffer = Buffer.getBufferStart();
   return count == 0 ||
          std::all_of(buffer.begin(), buffer.begin() + count,
-                     [](char c) { return ::isprint(c) || ::isspace(c); });
+                     [](char c) { return isPrint(c) || ::isspace(c); });
 }
 
 // Read the profile variant flag from the header: ":FE" means this is a FE
diff --git a/llvm/lib/Support/StringExtras.cpp b/llvm/lib/Support/StringExtras.cpp
index d566b72a8d0..386d74a4798 100644
--- a/llvm/lib/Support/StringExtras.cpp
+++ b/llvm/lib/Support/StringExtras.cpp
@@ -61,7 +61,7 @@ void llvm::SplitString(StringRef Source,
 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 != '"')
+    if (isPrint(C) && C != '\\' && C != '"')
       Out << C;
     else
       Out << '\\' << hexdigit(C >> 4) << hexdigit(C & 0x0F);
diff --git a/llvm/lib/Support/raw_ostream.cpp b/llvm/lib/Support/raw_ostream.cpp
index b2260c1865e..1dae469958f 100644
--- a/llvm/lib/Support/raw_ostream.cpp
+++ b/llvm/lib/Support/raw_ostream.cpp
@@ -160,7 +160,7 @@ raw_ostream &raw_ostream::write_escaped(StringRef Str,
       *this << '\\' << '"';
       break;
     default:
-      if (std::isprint(c)) {
+      if (isPrint(c)) {
         *this << c;
         break;
       }
@@ -436,7 +436,7 @@ raw_ostream &raw_ostream::operator<<(const FormattedBytes &FB) {
 
       // Print the ASCII char values for each byte on this line
       for (uint8_t Byte : Line) {
-        if (isprint(Byte))
+        if (isPrint(Byte))
           *this << static_cast<char>(Byte);
         else
           *this << '.';
diff --git a/llvm/lib/Support/regengine.inc b/llvm/lib/Support/regengine.inc
index 62d8c267f22..41787aff124 100644
--- a/llvm/lib/Support/regengine.inc
+++ b/llvm/lib/Support/regengine.inc
@@ -1013,7 +1013,7 @@ pchar(int ch)
 {
 	static char pbuf[10];
 
-	if (isprint(ch) || ch == ' ')
+	if (isPrint(ch) || ch == ' ')
 		(void)snprintf(pbuf, sizeof pbuf, "%c", ch);
 	else
 		(void)snprintf(pbuf, sizeof pbuf, "\\%o", ch);