From b41ca8f2aeb085306fc8c1027fa621ce0a398fdc Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Sun, 21 Mar 2010 22:49:54 +0000
Subject: Keep track of the size/modification time of each file source-location
 entry in a precompiled header, so that we can detect modified files even when
 we miss in the stat cache.

llvm-svn: 99149
---
 clang/lib/Frontend/PCHReader.cpp | 17 ++++++++++++-----
 clang/lib/Frontend/PCHWriter.cpp |  7 +++++++
 2 files changed, 19 insertions(+), 5 deletions(-)

(limited to 'clang/lib/Frontend')

diff --git a/clang/lib/Frontend/PCHReader.cpp b/clang/lib/Frontend/PCHReader.cpp
index e659ff047d7..8fd81df098e 100644
--- a/clang/lib/Frontend/PCHReader.cpp
+++ b/clang/lib/Frontend/PCHReader.cpp
@@ -905,11 +905,18 @@ PCHReader::PCHReadResult PCHReader::ReadSLocEntryRecord(unsigned ID) {
       return Failure;
     }
 
-    if (Record.size() < 8) {
+    if (Record.size() < 10) {
       Error("source location entry is incorrect");
       return Failure;
     }
 
+    if ((off_t)Record[4] != File->getSize() ||
+        (time_t)Record[5] != File->getModificationTime()) {
+      Diag(diag::err_fe_pch_file_modified)
+        << Filename;
+      return Failure;
+    }
+
     FileID FID = SourceMgr.createFileID(File,
                                 SourceLocation::getFromRawEncoding(Record[1]),
                                        (SrcMgr::CharacteristicKind)Record[2],
@@ -920,10 +927,10 @@ PCHReader::PCHReadResult PCHReader::ReadSLocEntryRecord(unsigned ID) {
 
     // Reconstruct header-search information for this file.
     HeaderFileInfo HFI;
-    HFI.isImport = Record[4];
-    HFI.DirInfo = Record[5];
-    HFI.NumIncludes = Record[6];
-    HFI.ControllingMacroID = Record[7];
+    HFI.isImport = Record[6];
+    HFI.DirInfo = Record[7];
+    HFI.NumIncludes = Record[8];
+    HFI.ControllingMacroID = Record[9];
     if (Listener)
       Listener->ReadHeaderFileInfo(HFI, File->getUID());
     break;
diff --git a/clang/lib/Frontend/PCHWriter.cpp b/clang/lib/Frontend/PCHWriter.cpp
index 4752cd3ea6e..6c2d1424c80 100644
--- a/clang/lib/Frontend/PCHWriter.cpp
+++ b/clang/lib/Frontend/PCHWriter.cpp
@@ -921,6 +921,9 @@ static unsigned CreateSLocFileAbbrev(llvm::BitstreamWriter &Stream) {
   Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // Include location
   Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // Characteristic
   Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Line directives
+  // FileEntry fields.
+  Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 12)); // Size
+  Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 32)); // Modification time
   // HeaderFileInfo fields.
   Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isImport
   Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // DirInfo
@@ -1063,6 +1066,10 @@ void PCHWriter::WriteSourceManagerBlock(SourceManager &SourceMgr,
         // The source location entry is a file. The blob associated
         // with this entry is the file name.
 
+        // Emit size/modification time for this file.
+        Record.push_back(Content->Entry->getSize());
+        Record.push_back(Content->Entry->getModificationTime());
+
         // Emit header-search information associated with this file.
         HeaderFileInfo HFI;
         HeaderSearch &HS = PP.getHeaderSearchInfo();
-- 
cgit v1.2.3