Avoid O(n^2) string analysis when handling GNU __asm__ statements.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@269716 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/AST/Stmt.cpp b/lib/AST/Stmt.cpp
index 7dfa3a9df13ec98da5b5c3fa1013deffc954926b..f514ed21f474a9f5af75b963d82cb205cabeb384 100644 (file)
--- a/lib/AST/Stmt.cpp
+++ b/lib/AST/Stmt.cpp
@@ -503,6 +503,9 @@ unsigned GCCAsmStmt::AnalyzeAsmString(SmallVectorImpl<AsmStringPiece>&Pieces,
 
   bool HasVariants = !C.getTargetInfo().hasNoAsmVariants();
 
+  unsigned LastAsmStringToken = 0;
+  unsigned LastAsmStringOffset = 0;
+
   while (1) {
     // Done with the string?
     if (CurPtr == StrEnd) {
@@ -589,10 +592,12 @@ unsigned GCCAsmStmt::AnalyzeAsmString(SmallVectorImpl<AsmStringPiece>&Pieces,
 
       // (BeginLoc, EndLoc) represents the range of the operand we are currently
       // processing. Unlike Str, the range includes the leading '%'.
-      SourceLocation BeginLoc =
-          getAsmString()->getLocationOfByte(Percent - StrStart, SM, LO, TI);
-      SourceLocation EndLoc =
-          getAsmString()->getLocationOfByte(CurPtr - StrStart, SM, LO, TI);
+      SourceLocation BeginLoc = getAsmString()->getLocationOfByte(
+          Percent - StrStart, SM, LO, TI, &LastAsmStringToken,
+          &LastAsmStringOffset);
+      SourceLocation EndLoc = getAsmString()->getLocationOfByte(
+          CurPtr - StrStart, SM, LO, TI, &LastAsmStringToken,
+          &LastAsmStringOffset);
 
       Pieces.emplace_back(N, std::move(Str), BeginLoc, EndLoc);
       continue;
@@ -623,10 +628,12 @@ unsigned GCCAsmStmt::AnalyzeAsmString(SmallVectorImpl<AsmStringPiece>&Pieces,
 
       // (BeginLoc, EndLoc) represents the range of the operand we are currently
       // processing. Unlike Str, the range includes the leading '%'.
-      SourceLocation BeginLoc =
-          getAsmString()->getLocationOfByte(Percent - StrStart, SM, LO, TI);
-      SourceLocation EndLoc =
-          getAsmString()->getLocationOfByte(NameEnd + 1 - StrStart, SM, LO, TI);
+      SourceLocation BeginLoc = getAsmString()->getLocationOfByte(
+          Percent - StrStart, SM, LO, TI, &LastAsmStringToken,
+          &LastAsmStringOffset);
+      SourceLocation EndLoc = getAsmString()->getLocationOfByte(
+          NameEnd + 1 - StrStart, SM, LO, TI, &LastAsmStringToken,
+          &LastAsmStringOffset);
 
       Pieces.emplace_back(N, std::move(Str), BeginLoc, EndLoc);