Fix MemoryBuffer::getSTDIN to *not* return null if stdin is empty, this is a lame...

[oota-llvm.git] / lib / Support / SourceMgr.cpp

diff --git a/lib/Support/SourceMgr.cpp b/lib/Support/SourceMgr.cpp
index 123531e21db53aa7047344cec3f49a9fb878c55c..4b93f7f99a24b22950db0663ac0004da8b68ade2 100644 (file)
--- a/lib/Support/SourceMgr.cpp
+++ b/lib/Support/SourceMgr.cpp
@@ -18,7 +18,24 @@
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
+namespace {
+  struct LineNoCacheTy {
+    int LastQueryBufferID;
+    const char *LastQuery;
+    unsigned LineNoOfQuery;
+  };
+}
+
+static LineNoCacheTy *getCache(void *Ptr) {
+  return (LineNoCacheTy*)Ptr;
+}
+
+
 SourceMgr::~SourceMgr() {
+  // Delete the line # cache if allocated.
+  if (LineNoCacheTy *Cache = getCache(LineNoCache))
+    delete Cache;
+    
   while (!Buffers.empty()) {
     delete Buffers.back().Buffer;
     Buffers.pop_back();
@@ -71,8 +88,31 @@ unsigned SourceMgr::FindLineNumber(SMLoc Loc, int BufferID) const {
   
   const char *Ptr = Buff->getBufferStart();
 
+  // If we have a line number cache, and if the query is to a later point in the
+  // same file, start searching from the last query location.  This optimizes
+  // for the case when multiple diagnostics come out of one file in order.
+  if (LineNoCacheTy *Cache = getCache(LineNoCache))
+    if (Cache->LastQueryBufferID == BufferID && 
+        Cache->LastQuery <= Loc.getPointer()) {
+      Ptr = Cache->LastQuery;
+      LineNo = Cache->LineNoOfQuery;
+    }
+
+  // Scan for the location being queried, keeping track of the number of lines
+  // we see.
   for (; SMLoc::getFromPointer(Ptr) != Loc; ++Ptr)
     if (*Ptr == '\n') ++LineNo;
+  
+  
+  // Allocate the line number cache if it doesn't exist.
+  if (LineNoCache == 0)
+    LineNoCache = new LineNoCacheTy();
+  
+  // Update the line # cache.
+  LineNoCacheTy &Cache = *getCache(LineNoCache);
+  Cache.LastQueryBufferID = BufferID;
+  Cache.LastQuery = Ptr;
+  Cache.LineNoOfQuery = LineNo;
   return LineNo;
 }
 
@@ -90,17 +130,19 @@ void SourceMgr::PrintIncludeStack(SMLoc IncludeLoc, raw_ostream &OS) const {
 }
 
 
-void SourceMgr::PrintMessage(SMLoc Loc, const std::string &Msg, 
-                             const char *Type) const {
-  raw_ostream &OS = errs();
+/// GetMessage - Return an SMDiagnostic at the specified location with the
+/// specified string.
+///
+/// @param Type - If non-null, the kind of message (e.g., "error") which is
+/// prefixed to the message.
+SMDiagnostic SourceMgr::GetMessage(SMLoc Loc, const std::string &Msg,
+                                   const char *Type) const {
   
   // First thing to do: find the current buffer containing the specified
   // location.
   int CurBuf = FindBufferContainingLoc(Loc);
   assert(CurBuf != -1 && "Invalid or unspecified location!");
   
-  PrintIncludeStack(getBufferInfo(CurBuf).IncludeLoc, OS);
-  
   MemoryBuffer *CurMB = getBufferInfo(CurBuf).Buffer;
   
   
@@ -122,12 +164,21 @@ void SourceMgr::PrintMessage(SMLoc Loc, const std::string &Msg,
   }
   PrintedMsg += Msg;
   
-  
   // Print out the line.
-  SMDiagnostic(CurMB->getBufferIdentifier(), FindLineNumber(Loc, CurBuf),
-               Loc.getPointer()-LineStart, PrintedMsg,
-               std::string(LineStart, LineEnd)).Print(0, OS);
-  
+  return SMDiagnostic(CurMB->getBufferIdentifier(), FindLineNumber(Loc, CurBuf),
+                      Loc.getPointer()-LineStart, PrintedMsg,
+                      std::string(LineStart, LineEnd));
+}
+
+void SourceMgr::PrintMessage(SMLoc Loc, const std::string &Msg, 
+                             const char *Type) const {
+  raw_ostream &OS = errs();
+
+  int CurBuf = FindBufferContainingLoc(Loc);
+  assert(CurBuf != -1 && "Invalid or unspecified location!");
+  PrintIncludeStack(getBufferInfo(CurBuf).IncludeLoc, OS);
+
+  GetMessage(Loc, Msg, Type).Print(0, OS);
 }
 
 //===----------------------------------------------------------------------===//