From e44433c29e59a57ef1fac9cd252a2a98a0afb2e7 Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Mon, 18 Jan 2010 19:28:01 +0000
Subject: [PATCH] =?utf8?q?Print=20fix-it=20hints=20properly=20around=20tab?=
 =?utf8?q?s,=20from=20Christian=20Ad=C3=A5ker!?=
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@93750 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Frontend/TextDiagnosticPrinter.cpp | 36 ++++++++++++++++++++++++++
 test/Misc/tabstop.c                    | 20 ++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/lib/Frontend/TextDiagnosticPrinter.cpp b/lib/Frontend/TextDiagnosticPrinter.cpp
index fcefd4e358..83b4542caa 100644
--- a/lib/Frontend/TextDiagnosticPrinter.cpp
+++ b/lib/Frontend/TextDiagnosticPrinter.cpp
@@ -428,6 +428,42 @@ void TextDiagnosticPrinter::EmitCaretDiagnostic(SourceLocation Loc,
         }
       }
     }
+    // Now that we have the entire fixit line, expand the tabs in it.
+    // Since we don't want to insert spaces in the middle of a word,
+    // find each word and the column it should line up with and insert
+    // spaces until they match.
+    if (!FixItInsertionLine.empty()) {
+      unsigned FixItPos = 0;
+      unsigned LinePos = 0;
+      unsigned TabExpandedCol = 0;
+      unsigned LineLength = LineEnd - LineStart;
+
+      while (FixItPos < FixItInsertionLine.size() && LinePos < LineLength) {
+        // Find the next word in the FixIt line.
+        while (FixItPos < FixItInsertionLine.size() &&
+               FixItInsertionLine[FixItPos] == ' ')
+          ++FixItPos;
+        unsigned CharDistance = FixItPos - TabExpandedCol;
+
+        // Walk forward in the source line, keeping track of
+        // the tab-expanded column.
+        for (unsigned I = 0; I < CharDistance; ++I, ++LinePos)
+          if (LinePos >= LineLength || LineStart[LinePos] != '\t')
+            ++TabExpandedCol;
+          else
+            TabExpandedCol =
+              (TabExpandedCol/DiagOpts->TabStop + 1) * DiagOpts->TabStop;
+
+        // Adjust the fixit line to match this column.
+        FixItInsertionLine.insert(FixItPos, TabExpandedCol-FixItPos, ' ');
+        FixItPos = TabExpandedCol;
+
+        // Walk to the end of the word.
+        while (FixItPos < FixItInsertionLine.size() &&
+               FixItInsertionLine[FixItPos] != ' ')
+          ++FixItPos;
+      }
+    }
   }
 
   // If the source line is too long for our terminal, select only the
diff --git a/test/Misc/tabstop.c b/test/Misc/tabstop.c
index 3fabda76eb..66685c62d1 100644
--- a/test/Misc/tabstop.c
+++ b/test/Misc/tabstop.c
@@ -28,3 +28,23 @@ void* d =	1;
 //CHECK-5: {{^          void\* b = 1;}}
 //CHECK-5: {{^     void\* c = 1;}}
 //CHECK-5: {{^void\* d = 1;}}
+
+// Test code modification hints
+
+void f(void)
+{
+	if (0	& 1	== 1)
+	{}
+}
+
+// CHECK-3: {{^   }}if (0 & 1   == 1)
+// CHECK-3: {{^   }}        (       )
+// CHECK-3: {{^   }}    (    )
+
+// CHECK-4: {{^    }}if (0   & 1 == 1)
+// CHECK-4: {{^    }}          (     )
+// CHECK-4: {{^    }}    (      )
+
+// CHECK-5: {{^     }}if (0     & 1  == 1)
+// CHECK-5: {{^     }}            (      )
+// CHECK-5: {{^     }}    (        )
-- 
2.40.0