From 73af0ec4d0074ce1e9b1677b3525ed92f5fd00c7 Mon Sep 17 00:00:00 2001
From: Oleksandr Usov <a.s.usov@gmail.com>
Date: Mon, 12 Mar 2012 19:14:07 +0000
Subject: Issue #241 - handle depfiles generated by older versions of GCC

Older versions of GCC would produce broken depfiles when -MT or -MQ is used
    gcc43 -MT foo.o -MMD -MF foo.o.d -o foo.o -c foo.c
will result in the following depfile
    foo.o foo.o: <dependencies>

Parse multiple outputs unifying duplicates and correctly report errors if
they are different.
---
 src/depfile_parser.cc      | 16 ++++++++++++----
 src/depfile_parser.in.cc   | 16 ++++++++++++----
 src/depfile_parser_test.cc | 17 +++++++++++++++++
 3 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/src/depfile_parser.cc b/src/depfile_parser.cc
index 8f8f9fe..7219eb0 100644
--- a/src/depfile_parser.cc
+++ b/src/depfile_parser.cc
@@ -32,8 +32,10 @@
 bool DepfileParser::Parse(string* content, string* err) {
   // in: current parser input point.
   // end: end of input.
+  // parsing_targets: whether we are parsing targets or dependencies.
   char* in = &(*content)[0];
   char* end = in + content->size();
+  bool parsing_targets = true;
   while (in < end) {
     // out: current output point (typically same as in, but can fall behind
     // as we de-escape backslashes).
@@ -180,16 +182,22 @@ yy13:
     }
 
     int len = out - filename;
-    if (len > 0 && filename[len - 1] == ':')
+    const bool is_target = parsing_targets;
+    if (len > 0 && filename[len - 1] == ':') {
       len--;  // Strip off trailing colon, if any.
+      parsing_targets = false;
+    }
 
     if (len == 0)
       continue;
 
-    if (!out_.str_) {
-      out_ = StringPiece(filename, len);
-    } else {
+    if (!is_target) {
       ins_.push_back(StringPiece(filename, len));
+    } else if (!out_.str_) {
+      out_ = StringPiece(filename, len);
+    } else if (out_ != StringPiece(filename, len)) {
+      *err = "depfile has multiple output paths.";
+      return false;
     }
   }
   return true;
diff --git a/src/depfile_parser.in.cc b/src/depfile_parser.in.cc
index de1c38f..419ed8d 100644
--- a/src/depfile_parser.in.cc
+++ b/src/depfile_parser.in.cc
@@ -31,8 +31,10 @@
 bool DepfileParser::Parse(string* content, string* err) {
   // in: current parser input point.
   // end: end of input.
+  // parsing_targets: whether we are parsing targets or dependencies.
   char* in = &(*content)[0];
   char* end = in + content->size();
+  bool parsing_targets = true;
   while (in < end) {
     // out: current output point (typically same as in, but can fall behind
     // as we de-escape backslashes).
@@ -87,16 +89,22 @@ bool DepfileParser::Parse(string* content, string* err) {
     }
 
     int len = out - filename;
-    if (len > 0 && filename[len - 1] == ':')
+    const bool is_target = parsing_targets;
+    if (len > 0 && filename[len - 1] == ':') {
       len--;  // Strip off trailing colon, if any.
+      parsing_targets = false;
+    }
 
     if (len == 0)
       continue;
 
-    if (!out_.str_) {
-      out_ = StringPiece(filename, len);
-    } else {
+    if (!is_target) {
       ins_.push_back(StringPiece(filename, len));
+    } else if (!out_.str_) {
+      out_ = StringPiece(filename, len);
+    } else if (out_ != StringPiece(filename, len)) {
+      *err = "depfile has multiple output paths.";
+      return false;
     }
   }
   return true;
diff --git a/src/depfile_parser_test.cc b/src/depfile_parser_test.cc
index 43e677c..883926a 100644
--- a/src/depfile_parser_test.cc
+++ b/src/depfile_parser_test.cc
@@ -102,3 +102,20 @@ TEST_F(DepfileParserTest, Escapes) {
             parser_.out_.AsString());
   ASSERT_EQ(0u, parser_.ins_.size());
 }
+
+TEST_F(DepfileParserTest, UnifyMultupleOutputs) {
+  // check that multiple duplicate targets are properly unified
+  string err;
+  EXPECT_TRUE(Parse("foo foo: x y z", &err));
+  ASSERT_EQ(parser_.out_.AsString(), "foo");
+  ASSERT_EQ(parser_.ins_.size(), 3);
+  EXPECT_EQ("x", parser_.ins_[0].AsString());
+  EXPECT_EQ("y", parser_.ins_[1].AsString());
+  EXPECT_EQ("z", parser_.ins_[2].AsString());
+}
+
+TEST_F(DepfileParserTest, RejectMultipleDifferentOutputs) {
+  // check that multiple different outputs are rejected by the parser
+  string err;
+  EXPECT_FALSE(Parse("foo bar: x y z", &err));
+}
-- 
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