diff mbox series

[v3] preprocessor: More escapes for Makefile rules (-M option) [PR41329, PR121450]

Message ID 20250914162315.12947-1-joergboe@snafu.de
State New
Headers
Series [v3] preprocessor: More escapes for Makefile rules (-M option) [PR41329, PR121450] |

Commit Message

joergboe Sept. 14, 2025, 4:23 p.m. UTC 
  This patch adds support for more characters that are special to GNU make in
file-names.
Especially GNU make expects in rules that #, %, :, *, ? and [ characters
are preceded by a backslash to remove their special meaning.

	PR preprocessor/41329

	PR preprocessor/121450

libcpp/ChangeLog:

	* mkdeps.cc (munge): Quote additional characters: %, :, *, ? and [

gcc/testsuite/ChangeLog:

	* g++.dg/modules/dep-1_a.C: Adapt tescase
	* g++.dg/modules/dep-1_b.C: Likewise
	* g++.dg/modules/dep-2.C: Likewise
---
 gcc/testsuite/g++.dg/modules/dep-1_a.C |  4 ++--
 gcc/testsuite/g++.dg/modules/dep-1_b.C |  4 ++--
 gcc/testsuite/g++.dg/modules/dep-2.C   |  6 +++---
 libcpp/mkdeps.cc                       | 28 ++++++++++++++++----------
 4 files changed, 24 insertions(+), 18 deletions(-)

Comments

Joseph Myers Sept. 15, 2025, 7:02 p.m. UTC | #1 
On Sun, 14 Sep 2025, Joerg Boehmer wrote:

> This patch adds support for more characters that are special to GNU make in
> file-names.
> Especially GNU make expects in rules that #, %, :, *, ? and [ characters
> are preceded by a backslash to remove their special meaning.

This does not address my comments on the previous version.
diff mbox series

Patch

diff --git a/gcc/testsuite/g++.dg/modules/dep-1_a.C b/gcc/testsuite/g++.dg/modules/dep-1_a.C
index 3e92eeaef9f..f90c2378702 100644
--- a/gcc/testsuite/g++.dg/modules/dep-1_a.C
+++ b/gcc/testsuite/g++.dg/modules/dep-1_a.C
@@ -4,6 +4,6 @@  export module m:part;
 // { dg-module-cmi m:part }
 
 // All The Backslashes!
-// { dg-final { scan-file dep-1_a.d {\nm:part\.c\+\+-module: gcm.cache/m-part\.gcm} } }
+// { dg-final { scan-file dep-1_a.d {\nm\\:part\.c\+\+-module: gcm.cache/m-part\.gcm} } }
 // { dg-final { scan-file dep-1_a.d {\ngcm.cache/m-part\.gcm:| dep-1_a\.o} } }
-// { dg-final { scan-file dep-1_a.d {\n\.PHONY: m:part\.c\+\+-module} } }
+// { dg-final { scan-file dep-1_a.d {\n\.PHONY: m\\:part\.c\+\+-module} } }
diff --git a/gcc/testsuite/g++.dg/modules/dep-1_b.C b/gcc/testsuite/g++.dg/modules/dep-1_b.C
index 265ebfcda64..1ecb31c230e 100644
--- a/gcc/testsuite/g++.dg/modules/dep-1_b.C
+++ b/gcc/testsuite/g++.dg/modules/dep-1_b.C
@@ -3,8 +3,8 @@  export module m;
 // { dg-module-cmi m }
 
 export import :part;
-// { dg-final { scan-file dep-1_b.d {\ndep-1_b\.s gcm.cache/m\.gcm: m:part\.c\+\+-module} } }
+// { dg-final { scan-file dep-1_b.d {\ndep-1_b\.s gcm.cache/m\.gcm: m\\:part\.c\+\+-module} } }
 // { dg-final { scan-file dep-1_b.d {\nm\.c\+\+-module: gcm.cache/m\.gcm} } }
 // { dg-final { scan-file dep-1_b.d {\n\.PHONY: m\.c\+\+-module} } }
 // { dg-final { scan-file dep-1_b.d {\ngcm.cache/m\.gcm:| dep-1_b.o} } }
-// { dg-final { scan-file dep-1_b.d {\nCXX_IMPORTS \+= m:part\.c\+\+-module} } }
+// { dg-final { scan-file dep-1_b.d {\nCXX_IMPORTS \+= m\\:part\.c\+\+-module} } }
diff --git a/gcc/testsuite/g++.dg/modules/dep-2.C b/gcc/testsuite/g++.dg/modules/dep-2.C
index 3c869755785..eca5653f548 100644
--- a/gcc/testsuite/g++.dg/modules/dep-2.C
+++ b/gcc/testsuite/g++.dg/modules/dep-2.C
@@ -5,8 +5,8 @@  module m:part;
 // { dg-module-cmi !m:part }
 
 // All The Backslashes!
-// { dg-final { scan-file dep-2.d {\nm:part\.c\+\+-module: gcm.cache/m-part\.gcm} } }
-// { dg-final { scan-file dep-2.d {\ngcm.cache/m:part\.gcm:| dep-2\.o} } }
-// { dg-final { scan-file dep-2.d {\n\.PHONY: m:part\.c\+\+-module} } }
+// { dg-final { scan-file dep-2.d {\nm\\:part\.c\+\+-module: gcm.cache/m-part\.gcm} } }
+// { dg-final { scan-file dep-2.d {\ngcm.cache/m\\:part\.gcm:| dep-2\.o} } }
+// { dg-final { scan-file dep-2.d {\n\.PHONY: m\\:part\.c\+\+-module} } }
 
 // { dg-final { scan-file dep-2.i {\nmodule m:part;\n} } }
diff --git a/libcpp/mkdeps.cc b/libcpp/mkdeps.cc
index a4bea6e47d4..40fd5062a8a 100644
--- a/libcpp/mkdeps.cc
+++ b/libcpp/mkdeps.cc
@@ -121,10 +121,11 @@  public:
 };
 
 /* Apply Make quoting to STR, TRAIL.  Note that it's not possible to
-   quote all such characters - e.g. \n, %, *, ?, [, \ (in some
+   quote all such characters - e.g. \n, ;, =, |, \ (in some
    contexts), and ~ are not properly handled.  It isn't possible to
    get this right in any current version of Make.  (??? Still true?
-   Old comment referred to 3.76.1.)  */
+   Old comment referred to 4.4.1.) However there are still issues with
+   this special characters in some contexts.  */
 
 static const char *
 munge (const char *str, const char *trail = nullptr)
@@ -157,18 +158,23 @@  munge (const char *str, const char *trail = nullptr)
 
 	    case ' ':
 	    case '\t':
-	      /* GNU make uses a weird quoting scheme for white space.
-		 A space or tab preceded by 2N+1 backslashes
-		 represents N backslashes followed by space; a space
-		 or tab preceded by 2N backslashes represents N
-		 backslashes at the end of a file name; and
-		 backslashes in other contexts should not be
+	    case '#':
+	    case ':':
+	    case '*':
+	    case '?':
+	    case '[':
+	    case '%':
+	      /* GNU make uses a weird quoting scheme for those special
+		 characters in the context of a target or prerequisite.
+		 A special character preceded by 2N+1 backslashes
+		 represents N backslashes and the following character
+		 loses its special meaning; a special
+		 character preceded by 2N backslashes represents N
+		 backslashes and the special meaning of the character is
+		 retained; and backslashes in other contexts should not be
 		 doubled.  */
 	      while (slashes--)
 		buf[dst++] = '\\';
-	      /* FALLTHROUGH  */
-
-	    case '#':
 	      buf[dst++] = '\\';
 	      /* FALLTHROUGH  */