From: Ted Kremenek <kremenek@apple.com>
Date: Thu, 10 Mar 2011 20:03:42 +0000 (+0000)
Subject: Profiling showed that 'CheckImplicitConversions' was very slow because of the call... 
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=ef9ff88f54ff26ac9782d98a34b74aa424149be1;p=clang

Profiling showed that 'CheckImplicitConversions' was very slow because of the call to getSpellingLoc().  On 'aes.c'
in the LLVM test suite, this function was consuming 7.4% of -fsyntax-only time.  This change fixes this issue
by delaying the check that the warning would be issued within a system macro by as long as possible.  The
main negative of this change is now the logic for this check is done in multiple places in this function instead
of just in one place up front.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@127425 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index cdcab31eef..10773309a3 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -2762,6 +2762,11 @@ std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) {
   return ValueInRange.toString(10);
 }
 
+static bool isFromSystemMacro(Sema &S, SourceLocation loc) {
+  SourceManager &smgr = S.Context.getSourceManager();
+  return loc.isMacroID() && smgr.isInSystemHeader(smgr.getSpellingLoc(loc));
+}
+  
 void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
                              SourceLocation CC, bool *ICContext = 0) {
   if (E->isTypeDependent() || E->isValueDependent()) return;
@@ -2771,11 +2776,12 @@ void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
   if (Source == Target) return;
   if (Target->isDependentType()) return;
 
-  // If the conversion context location is invalid or instantiated
-  // from a system macro, don't complain.
-  if (CC.isInvalid() ||
-      (CC.isMacroID() && S.Context.getSourceManager().isInSystemHeader(
-                           S.Context.getSourceManager().getSpellingLoc(CC))))
+  // If the conversion context location is invalid don't complain.
+  // We also don't want to emit a warning if the issue occurs from the
+  // instantiation of a system macro.  The problem is that 'getSpellingLoc()'
+  // is slow, so we delay this check as long as possible.  Once we detect
+  // we are in that scenario, we just return.
+  if (CC.isInvalid())
     return;
 
   // Never diagnose implicit casts to bool.
@@ -2784,8 +2790,11 @@ void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
 
   // Strip vector types.
   if (isa<VectorType>(Source)) {
-    if (!isa<VectorType>(Target))
+    if (!isa<VectorType>(Target)) {
+      if (isFromSystemMacro(S, CC))
+        return;
       return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar);
+    }
 
     Source = cast<VectorType>(Source)->getElementType().getTypePtr();
     Target = cast<VectorType>(Target)->getElementType().getTypePtr();
@@ -2793,8 +2802,12 @@ void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
 
   // Strip complex types.
   if (isa<ComplexType>(Source)) {
-    if (!isa<ComplexType>(Target))
+    if (!isa<ComplexType>(Target)) {
+      if (isFromSystemMacro(S, CC))
+        return;
+
       return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar);
+    }
 
     Source = cast<ComplexType>(Source)->getElementType().getTypePtr();
     Target = cast<ComplexType>(Target)->getElementType().getTypePtr();
@@ -2822,13 +2835,19 @@ void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
             return;
         }
 
+        if (isFromSystemMacro(S, CC))
+          return;
+
         DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision);
       }
       return;
     }
 
-    // If the target is integral, always warn.
+    // If the target is integral, always warn.    
     if ((TargetBT && TargetBT->isInteger())) {
+      if (isFromSystemMacro(S, CC))
+        return;
+      
       Expr *InnerE = E->IgnoreParenImpCasts();
       if (FloatingLiteral *LiteralExpr = dyn_cast<FloatingLiteral>(InnerE)) {
         DiagnoseImpCast(S, LiteralExpr, T, CC,
@@ -2852,6 +2871,9 @@ void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
     // TODO: this should happen for bitfield stores, too.
     llvm::APSInt Value(32);
     if (E->isIntegerConstantExpr(Value, S.Context)) {
+      if (isFromSystemMacro(S, CC))
+        return;
+
       std::string PrettySourceValue = Value.toString(10);
       std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange);
 
@@ -2863,6 +2885,10 @@ void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
 
     // People want to build with -Wshorten-64-to-32 and not -Wconversion
     // and by god we'll let them.
+    
+    if (isFromSystemMacro(S, CC))
+      return;
+    
     if (SourceRange.Width == 64 && TargetRange.Width == 32)
       return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32);
     return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision);
@@ -2871,6 +2897,10 @@ void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
   if ((TargetRange.NonNegative && !SourceRange.NonNegative) ||
       (!TargetRange.NonNegative && SourceRange.NonNegative &&
        SourceRange.Width == TargetRange.Width)) {
+        
+    if (isFromSystemMacro(S, CC))
+      return;
+
     unsigned DiagID = diag::warn_impcast_integer_sign;
 
     // Traditionally, gcc has warned about this under -Wsign-compare.
@@ -2893,9 +2923,13 @@ void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
            SourceEnum->getDecl()->getTypedefForAnonDecl()) &&
           (TargetEnum->getDecl()->getIdentifier() ||
            TargetEnum->getDecl()->getTypedefForAnonDecl()) &&
-          SourceEnum != TargetEnum)
+          SourceEnum != TargetEnum) {
+        if (isFromSystemMacro(S, CC))
+          return;
+
         return DiagnoseImpCast(S, E, T, CC, 
                                diag::warn_impcast_different_enum_types);
+      }
   
   return;
 }