Add support for __builtin_os_log_format[_buffer_size]

These new builtins support a mechanism for logging OS events, using a
printf-like format string to specify the layout of data in a buffer.
The _buffer_size version of the builtin can be used to determine the size
of the buffer to allocate to hold the data, and then __builtin_os_log_format
can write data into that buffer. This implements format checking to report
mismatches between the format string and the data arguments. Most of this
code was written by Chris Willmore.

Differential Revision: https://reviews.llvm.org/D25888

llvm-svn: 284990

1 files changed, 41 insertions, 2 deletions

diff --git a/clang/lib/Analysis/PrintfFormatString.cpp b/clang/lib/Analysis/PrintfFormatString.cpp
index ac6cef9..ed7193e 100644
--- a/clang/lib/Analysis/PrintfFormatString.cpp
+++ b/clang/lib/Analysis/PrintfFormatString.cpp
@@ -119,6 +119,39 @@ static PrintfSpecifierResult ParsePrintfSpecifier(FormatStringHandler &H,
     return true;
   }
 
+  const char *OSLogVisibilityFlagsStart = nullptr,
+             *OSLogVisibilityFlagsEnd = nullptr;
+  if (*I == '{') {
+    OSLogVisibilityFlagsStart = I++;
+    // Find the end of the modifier.
+    while (I != E && *I != '}') {
+      I++;
+    }
+    if (I == E) {
+      if (Warn)
+        H.HandleIncompleteSpecifier(Start, E - Start);
+      return true;
+    }
+    assert(*I == '}');
+    OSLogVisibilityFlagsEnd = I++;
+
+    // Just see if 'private' or 'public' is the first word. os_log itself will
+    // do any further parsing.
+    const char *P = OSLogVisibilityFlagsStart + 1;
+    while (P < OSLogVisibilityFlagsEnd && isspace(*P))
+      P++;
+    const char *WordStart = P;
+    while (P < OSLogVisibilityFlagsEnd && (isalnum(*P) || *P == '_'))
+      P++;
+    const char *WordEnd = P;
+    StringRef Word(WordStart, WordEnd - WordStart);
+    if (Word == "private") {
+      FS.setIsPrivate(WordStart);
+    } else if (Word == "public") {
+      FS.setIsPublic(WordStart);
+    }
+  }
+
   // Look for flags (if any).
   bool hasMore = true;
   for ( ; I != E; ++I) {
@@ -253,6 +286,10 @@ static PrintfSpecifierResult ParsePrintfSpecifier(FormatStringHandler &H,
     // POSIX specific.
     case 'C': k = ConversionSpecifier::CArg; break;
     case 'S': k = ConversionSpecifier::SArg; break;
+    // Apple extension for os_log
+    case 'P':
+      k = ConversionSpecifier::PArg;
+      break;
     // Objective-C.
     case '@': k = ConversionSpecifier::ObjCObjArg; break;
     // Glibc specific.
@@ -301,7 +338,7 @@ static PrintfSpecifierResult ParsePrintfSpecifier(FormatStringHandler &H,
                                            conversionPosition);
     return true;
   }
-  
+
   PrintfConversionSpecifier CS(conversionPosition, k);
   FS.setConversionSpecifier(CS);
   if (CS.consumesDataArgument() && !FS.usesPositionalArg())
@@ -541,6 +578,7 @@ ArgType PrintfSpecifier::getArgType(ASTContext &Ctx,
         return Ctx.IntTy;
       return ArgType(Ctx.WideCharTy, "wchar_t");
     case ConversionSpecifier::pArg:
+    case ConversionSpecifier::PArg:
       return ArgType::CPointerTy;
     case ConversionSpecifier::ObjCObjArg:
       return ArgType::ObjCPointerTy;
@@ -900,7 +938,7 @@ bool PrintfSpecifier::hasValidPrecision() const {
   if (Precision.getHowSpecified() == OptionalAmount::NotSpecified)
     return true;
 
-  // Precision is only valid with the diouxXaAeEfFgGs conversions
+  // Precision is only valid with the diouxXaAeEfFgGsP conversions
   switch (CS.getKind()) {
   case ConversionSpecifier::dArg:
   case ConversionSpecifier::DArg:
@@ -922,6 +960,7 @@ bool PrintfSpecifier::hasValidPrecision() const {
   case ConversionSpecifier::sArg:
   case ConversionSpecifier::FreeBSDrArg:
   case ConversionSpecifier::FreeBSDyArg:
+  case ConversionSpecifier::PArg:
     return true;
 
   default: