This is a rebased version of this patch from back in April:
v2: https://gcc.gnu.org/ml/gcc-patches/2015-04/msg00944.html
which in turn is a rewrite of this one:
v1: https://gcc.gnu.org/ml/gcc-patches/2015-03/msg01087.html
The idea is to more gracefully handle merger conflict markers
in the source code being compiled. Specifically, in the C and
C++ frontends, if we're about to emit an error, see if the
source code is at a merger conflict marker, and if so, emit
a more specific message, so that the user gets this:
foo.c:1:1: error: source file contains patch conflict marker
<<<<<<< HEAD
^
rather than this gobbledegook:
foo.c:1:1: error: expected identifier or '(' before '<<' token
<<<<<<< HEAD
^
It's something of a "fit and finish" cosmetic item, but these
things add up.
Successfully bootstrapped®rtested on x86_64-pc-linux-gnu;
adds 82 new PASSes to g++.sum and 27 new PASSes to gcc.sum.
OK for trunk?
This implementation works by looking at the token stream, which
is slightly clunky; an alternative way of doing it would be to directly
look at the line the error occurs in and to see if it begins with a
conflict marker. Would that be preferable?
gcc/c-family/ChangeLog:
* c-common.h (conflict_marker_get_final_tok_kind): New prototype.
* c-lex.c (conflict_marker_get_final_tok_kind): New function.
gcc/c/ChangeLog:
* c-parser.c (struct c_parser): Expand array "tokens_buf" from 2
to 4.
(c_parser_peek_nth_token): New function.
(c_parser_peek_conflict_marker): New function.
(c_parser_error): Detect patch conflict markers and report them as
such.
gcc/cp/ChangeLog:
* parser.c (cp_lexer_peek_conflict_marker): New function.
(cp_parser_error): Detect patch conflict markers and report them
as such.
gcc/testsuite/ChangeLog:
* c-c++-common/patch-conflict-markers-1.c: New testcase.
* c-c++-common/patch-conflict-markers-2.c: Likewise.
* c-c++-common/patch-conflict-markers-3.c: Likewise.
* c-c++-common/patch-conflict-markers-4.c: Likewise.
* c-c++-common/patch-conflict-markers-5.c: Likewise.
* c-c++-common/patch-conflict-markers-6.c: Likewise.
* c-c++-common/patch-conflict-markers-7.c: Likewise.
* c-c++-common/patch-conflict-markers-8.c: Likewise.
* c-c++-common/patch-conflict-markers-9.c: Likewise.
* g++.dg/patch-conflict-markers-1.C: Likewise.
---
gcc/c-family/c-common.h | 4 ++
gcc/c-family/c-lex.c | 26 +++++++++++
gcc/c/c-parser.c | 53 +++++++++++++++++++++-
gcc/cp/parser.c | 34 ++++++++++++++
.../c-c++-common/patch-conflict-markers-1.c | 9 ++++
.../c-c++-common/patch-conflict-markers-2.c | 2 +
.../c-c++-common/patch-conflict-markers-3.c | 11 +++++
.../c-c++-common/patch-conflict-markers-4.c | 11 +++++
.../c-c++-common/patch-conflict-markers-5.c | 11 +++++
.../c-c++-common/patch-conflict-markers-6.c | 38 ++++++++++++++++
.../c-c++-common/patch-conflict-markers-7.c | 6 +++
.../c-c++-common/patch-conflict-markers-8.c | 4 ++
.../c-c++-common/patch-conflict-markers-9.c | 8 ++++
gcc/testsuite/g++.dg/patch-conflict-markers-1.C | 13 ++++++
14 files changed, 228 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/c-c++-common/patch-conflict-markers-1.c
create mode 100644 gcc/testsuite/c-c++-common/patch-conflict-markers-2.c
create mode 100644 gcc/testsuite/c-c++-common/patch-conflict-markers-3.c
create mode 100644 gcc/testsuite/c-c++-common/patch-conflict-markers-4.c
create mode 100644 gcc/testsuite/c-c++-common/patch-conflict-markers-5.c
create mode 100644 gcc/testsuite/c-c++-common/patch-conflict-markers-6.c
create mode 100644 gcc/testsuite/c-c++-common/patch-conflict-markers-7.c
create mode 100644 gcc/testsuite/c-c++-common/patch-conflict-markers-8.c
create mode 100644 gcc/testsuite/c-c++-common/patch-conflict-markers-9.c
create mode 100644 gcc/testsuite/g++.dg/patch-conflict-markers-1.C
diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index 4b5cac8..7ca9497 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -1090,6 +1090,10 @@ extern void c_genericize (tree);
extern int c_gimplify_expr (tree *, gimple_seq *, gimple_seq *);
extern tree c_build_bind_expr (location_t, tree, tree);
+/* In c-lex.c. */
+extern enum cpp_ttype
+conflict_marker_get_final_tok_kind (enum cpp_ttype tok1_kind);
+
/* In c-pch.c */
extern void pch_init (void);
extern void pch_cpp_save_state (void);
diff --git a/gcc/c-family/c-lex.c b/gcc/c-family/c-lex.c
index c69f4a6..6fc63eb 100644
--- a/gcc/c-family/c-lex.c
+++ b/gcc/c-family/c-lex.c
@@ -1269,3 +1269,29 @@ lex_charconst (const cpp_token *token)
return value;
}
+
+/* Helper function for c_parser_peek_conflict_marker
+ and cp_lexer_peek_conflict_marker.
+ Given a possible patch conflict marker token of kind TOK1_KIND
+ consisting of a pair of characters, get the token kind for the
+ standalone final character. */
+
+enum cpp_ttype
+conflict_marker_get_final_tok_kind (enum cpp_ttype tok1_kind)
+{
+ switch (tok1_kind)
+ {
+ default: gcc_unreachable ();
+ case CPP_LSHIFT:
+ /* "<<" and '<' */
+ return CPP_LESS;
+
+ case CPP_EQ_EQ:
+ /* "==" and '=' */
+ return CPP_EQ;
+
+ case CPP_RSHIFT:
+ /* ">>" and '>' */
+ return CPP_GREATER;
+ }
+}
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index c8c6a2d..a2d7ef6 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -181,8 +181,8 @@ struct GTY(()) c_parser {
/* The look-ahead tokens. */
c_token * GTY((skip)) tokens;
/* Buffer for look-ahead tokens. */
- c_token tokens_buf[2];
- /* How many look-ahead tokens are available (0, 1 or 2, or
+ c_token tokens_buf[4];
+ /* How many look-ahead tokens are available (0 - 4, or
more if parsing from pre-lexed tokens). */
unsigned int tokens_avail;
/* True if a syntax error is being recovered from; false otherwise.
@@ -471,6 +471,20 @@ c_parser_peek_2nd_token (c_parser *parser)
return &parser->tokens[1];
}
+/* Return a pointer to the Nth token from PARSER, reading it
+ in if necessary. The N-1th token is already read in. */
+
+static c_token *
+c_parser_peek_nth_token (c_parser *parser, unsigned int n)
+{
+ if (parser->tokens_avail >= n)
+ return &parser->tokens[n - 1];
+ gcc_assert (parser->tokens_avail == n - 1);
+ c_lex_one_token (parser, &parser->tokens[n - 1]);
+ parser->tokens_avail = n;
+ return &parser->tokens[n - 1];
+}
+
/* Return true if TOKEN can start a type name,
false otherwise. */
static bool
@@ -808,6 +822,30 @@ c_parser_set_source_position_from_token (c_token *token)
}
}
+/* Helper function for c_parser_error.
+ Having peeked a token of kind TOK1_KIND that might signify
+ a patch conflict marker, peek successor tokens to determine
+ if we actually do have a patch conflict marker.
+ Specifically, we consider a run of 7 '<', '=' or '>' characters
+ as a patch conflict marker.
+ These come through the lexer as three pairs and a single,
+ e.g. three CPP_LSHIFT ("<<") and a CPP_LESS ('<'). */
+
+static bool
+c_parser_peek_conflict_marker (c_parser *parser, enum cpp_ttype tok1_kind)
+{
+ c_token *token2 = c_parser_peek_2nd_token (parser);
+ if (token2->type != tok1_kind)
+ return false;
+ c_token *token3 = c_parser_peek_nth_token (parser, 3);
+ if (token3->type != tok1_kind)
+ return false;
+ c_token *token4 = c_parser_peek_nth_token (parser, 4);
+ if (token4->type != conflict_marker_get_final_tok_kind (tok1_kind))
+ return false;
+ return true;
+}
+
/* Issue a diagnostic of the form
FILE:LINE: MESSAGE before TOKEN
where TOKEN is the next token in the input stream of PARSER.
@@ -829,6 +867,17 @@ c_parser_error (c_parser *parser, const char *gmsgid)
parser->error = true;
if (!gmsgid)
return;
+
+ /* If this is actually a patch conflict marker, report it as such. */
+ if (token->type == CPP_LSHIFT
+ || token->type == CPP_RSHIFT
+ || token->type == CPP_EQ_EQ)
+ if (c_parser_peek_conflict_marker (parser, token->type))
+ {
+ error_at (token->location, "source file contains patch conflict
marker");
+ return;
+ }
+
/* This diagnostic makes more sense if it is tagged to the line of
the token we just peeked at. */
c_parser_set_source_position_from_token (token);
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 7555bf3..6b6bd29 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -2632,6 +2632,30 @@ cp_parser_is_keyword (cp_token* token, enum rid keyword)
return token->keyword == keyword;
}
+/* Helper function for cp_parser_error.
+ Having peeked a token of kind TOK1_KIND that might signify
+ a patch conflict marker, peek successor tokens to determine
+ if we actually do have a patch conflict marker.
+ Specifically, we consider a run of 7 '<', '=' or '>' characters
+ as a patch conflict marker.
+ These come through the lexer as three pairs and a single,
+ e.g. three CPP_LSHIFT tokens ("<<") and a CPP_LESS token ('<'). */
+
+static bool
+cp_lexer_peek_conflict_marker (cp_lexer *lexer, enum cpp_ttype tok1_kind)
+{
+ cp_token *token2 = cp_lexer_peek_nth_token (lexer, 2);
+ if (token2->type != tok1_kind)
+ return false;
+ cp_token *token3 = cp_lexer_peek_nth_token (lexer, 3);
+ if (token3->type != tok1_kind)
+ return false;
+ cp_token *token4 = cp_lexer_peek_nth_token (lexer, 4);
+ if (token4->type != conflict_marker_get_final_tok_kind (tok1_kind))
+ return false;
+ return true;
+}
+
/* If not parsing tentatively, issue a diagnostic of the form
FILE:LINE: MESSAGE before TOKEN
where TOKEN is the next token in the input stream. MESSAGE
@@ -2656,6 +2680,16 @@ cp_parser_error (cp_parser* parser, const char* gmsgid)
return;
}
+ /* If this is actually a patch conflict marker, report it as such. */
+ if (token->type == CPP_LSHIFT
+ || token->type == CPP_RSHIFT
+ || token->type == CPP_EQ_EQ)
+ if (cp_lexer_peek_conflict_marker (parser->lexer, token->type))
+ {
+ error_at (token->location, "source file contains patch conflict
marker");
+ return;
+ }
+
c_parse_error (gmsgid,
/* Because c_parser_error does not understand
CPP_KEYWORD, keywords are treated like
diff --git a/gcc/testsuite/c-c++-common/patch-conflict-markers-1.c
b/gcc/testsuite/c-c++-common/patch-conflict-markers-1.c
new file mode 100644
index 0000000..71e9fa7
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/patch-conflict-markers-1.c
@@ -0,0 +1,9 @@
+int p;
+
+<<<<<<< HEAD /* { dg-error "patch conflict marker" } */
+extern int some_var;
+======= /* { dg-error "patch conflict marker" } */
+extern short some_var; /* this line would lead to a warning */
+>>>>>>> Some commit message /* { dg-error "patch conflict marker" } */
+
+int q;
diff --git a/gcc/testsuite/c-c++-common/patch-conflict-markers-2.c
b/gcc/testsuite/c-c++-common/patch-conflict-markers-2.c
new file mode 100644
index 0000000..79030ee
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/patch-conflict-markers-2.c
@@ -0,0 +1,2 @@
+/* This should not be flagged as a patch conflict marker. */
+const char *msg = "<<<<<<< ";
diff --git a/gcc/testsuite/c-c++-common/patch-conflict-markers-3.c
b/gcc/testsuite/c-c++-common/patch-conflict-markers-3.c
new file mode 100644
index 0000000..be956b2
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/patch-conflict-markers-3.c
@@ -0,0 +1,11 @@
+/* Ensure we can handle unterminated conflict markers. */
+
+int p;
+
+<<<<<<< HEAD /* { dg-error "patch conflict marker" } */
+
+int q;
+
+<<<<<<< HEAD /* { dg-error "patch conflict marker" } */
+
+int r;
diff --git a/gcc/testsuite/c-c++-common/patch-conflict-markers-4.c
b/gcc/testsuite/c-c++-common/patch-conflict-markers-4.c
new file mode 100644
index 0000000..ec3730c
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/patch-conflict-markers-4.c
@@ -0,0 +1,11 @@
+/* Ensure we can handle mismatched conflict markers. */
+
+int p;
+
+>>>>>>> Some commit message /* { dg-error "patch conflict marker" } */
+
+int q;
+
+>>>>>>> Some other commit message /* { dg-error "patch conflict marker" } */
+
+int r;
diff --git a/gcc/testsuite/c-c++-common/patch-conflict-markers-5.c
b/gcc/testsuite/c-c++-common/patch-conflict-markers-5.c
new file mode 100644
index 0000000..816a97e
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/patch-conflict-markers-5.c
@@ -0,0 +1,11 @@
+/* Ensure we can handle mismatched conflict markers. */
+
+int p;
+
+======= /* { dg-error "patch conflict marker" } */
+
+int q;
+
+======= /* { dg-error "patch conflict marker" } */
+
+int r;
diff --git a/gcc/testsuite/c-c++-common/patch-conflict-markers-6.c
b/gcc/testsuite/c-c++-common/patch-conflict-markers-6.c
new file mode 100644
index 0000000..74ea2d5
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/patch-conflict-markers-6.c
@@ -0,0 +1,38 @@
+/* Branch coverage of patch conflict marker detection:
+ none of these should be reported as patch conflict markers. */
+
+int a0;
+
+<< HEAD /* { dg-error "expected" } */
+
+int a1;
+
+<<<< HEAD /* { dg-error "expected" } */
+
+int a2;
+
+<<<<<< HEAD /* { dg-error "expected" } */
+
+int b0;
+
+== HEAD /* { dg-error "expected" } */
+
+int b1;
+
+==== HEAD /* { dg-error "expected" } */
+
+int b2;
+
+====== HEAD /* { dg-error "expected" } */
+
+int c0;
+
+>> HEAD /* { dg-error "expected" } */
+
+int c1;
+
+>>>> HEAD /* { dg-error "expected" } */
+
+int c2;
+
+>>>>>> HEAD /* { dg-error "expected" } */
diff --git a/gcc/testsuite/c-c++-common/patch-conflict-markers-7.c
b/gcc/testsuite/c-c++-common/patch-conflict-markers-7.c
new file mode 100644
index 0000000..2b5d4e6
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/patch-conflict-markers-7.c
@@ -0,0 +1,6 @@
+/* It's valid to stringize the "<<<<<<<"; don't
+ report it as a patch conflict marker. */
+#define str(s) #s
+const char *s = str(
+<<<<<<<
+);
diff --git a/gcc/testsuite/c-c++-common/patch-conflict-markers-8.c
b/gcc/testsuite/c-c++-common/patch-conflict-markers-8.c
new file mode 100644
index 0000000..90d75b0
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/patch-conflict-markers-8.c
@@ -0,0 +1,4 @@
+/* A macro that's never expanded shouldn't be reported as a patch
+ conflict marker. */
+#define foo \
+<<<<<<<
diff --git a/gcc/testsuite/c-c++-common/patch-conflict-markers-9.c
b/gcc/testsuite/c-c++-common/patch-conflict-markers-9.c
new file mode 100644
index 0000000..5c1e663
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/patch-conflict-markers-9.c
@@ -0,0 +1,8 @@
+/* It's valid to have
+<<<<<<<
+ inside both
+ comments (as above), and within string literals. */
+const char *s = "\
+<<<<<<<";
+
+/* The above shouldn't be reported as errors. */
diff --git a/gcc/testsuite/g++.dg/patch-conflict-markers-1.C
b/gcc/testsuite/g++.dg/patch-conflict-markers-1.C
new file mode 100644
index 0000000..ae19193
--- /dev/null
+++ b/gcc/testsuite/g++.dg/patch-conflict-markers-1.C
@@ -0,0 +1,13 @@
+/* Ensure that we don't complain about patch conflict markers on
+ valid template argument lists, valid in C++11 onwards. */
+// { dg-options "-std=c++11" }
+
+template <typename T>
+struct foo
+{
+ T t;
+};
+
+foo <foo <foo <foo <foo <foo <foo <int
+>>>>>>> f;
+// The above line is valid C++11, and isn't a patch conflict marker
--
1.8.5.3
