public inbox for gdb-patches@sourceware.org
 help / color / mirror / Atom feed
* [PATCH v2] gdb: Fix issue with Clang CLI macros
@ 2022-10-17 10:26 Bruno Larsen
  2022-10-17 12:32 ` Simon Marchi
  2022-10-17 13:22 ` Simon Marchi
  0 siblings, 2 replies; 6+ messages in thread
From: Bruno Larsen @ 2022-10-17 10:26 UTC (permalink / raw)
  To: gdb-patches

Clang up to the current version adds macros that were defined in the
command line or by "other means", according to the Dwarf specification,
after the last DW_MACRO_end_file, instead of before the first
DW_MACRO_start_file, as the specification dictates.  When GDB reads the
macros after the last file is closed, the macros never end up "in scope"
and so we can't print them.  This has been submitted as a bug to Clang
developers, and PR macros/29034 was opened for GDB to keep track of
this.

Seeing as there is no expected date for it to be fixed, a workaround was
added for all current versions of Clang.  The workaround detects when
the main file would be closed and if the producer is clang, and turns
that operation into a noop, so we keep a reference to the current_file
as those macros are read.

A test case was added to confirm the functionality.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29034
---
 gdb/dwarf2/cu.h                               |   1 +
 gdb/dwarf2/macro.c                            |  18 +++-
 gdb/dwarf2/macro.h                            |   2 +-
 gdb/dwarf2/read.c                             |  15 ++-
 gdb/dwarf2/read.h                             |   2 +
 gdb/producer.c                                |  26 +++++
 gdb/producer.h                                |   4 +
 gdb/testsuite/gdb.dwarf2/clang_cli_macros.exp | 101 ++++++++++++++++++
 8 files changed, 163 insertions(+), 6 deletions(-)
 create mode 100644 gdb/testsuite/gdb.dwarf2/clang_cli_macros.exp

diff --git a/gdb/dwarf2/cu.h b/gdb/dwarf2/cu.h
index 23cb3d21b2e..51638e71b19 100644
--- a/gdb/dwarf2/cu.h
+++ b/gdb/dwarf2/cu.h
@@ -264,6 +264,7 @@ struct dwarf2_cu
   bool producer_is_icc : 1;
   bool producer_is_icc_lt_14 : 1;
   bool producer_is_codewarrior : 1;
+  bool producer_is_clang : 1;
 
   /* When true, the file that we're processing is known to have
      debugging info for C++ namespaces.  GCC 3.3.x did not produce
diff --git a/gdb/dwarf2/macro.c b/gdb/dwarf2/macro.c
index 38c0fdfec73..c753dc300f2 100644
--- a/gdb/dwarf2/macro.c
+++ b/gdb/dwarf2/macro.c
@@ -445,7 +445,7 @@ dwarf_decode_macro_bytes (dwarf2_per_objfile *per_objfile,
 			  struct dwarf2_section_info *str_section,
 			  struct dwarf2_section_info *str_offsets_section,
 			  gdb::optional<ULONGEST> str_offsets_base,
-			  htab_t include_hash)
+			  htab_t include_hash, struct dwarf2_cu *cu)
 {
   struct objfile *objfile = per_objfile->objfile;
   enum dwarf_macro_record_type macinfo_type;
@@ -672,6 +672,16 @@ dwarf_decode_macro_bytes (dwarf2_per_objfile *per_objfile,
 	  if (! current_file)
 	    complaint (_("macro debug info has an unmatched "
 			 "`close_file' directive"));
+	  else if (current_file->included_by == nullptr
+		   && producer_is_clang (cu))
+	    {
+	      /* Clang, until the current version, misplaces macro definitions,
+		 putting them after the last DW_MACRO_end_file instead of
+		 before the first DW_MACRO_start_file.  */
+	      /* FIXME: Since at the time of writing there is no clang version
+		 with this bug fixed, we check for any clang producer.  This
+		 should be changed to producer_is_clang_lt_XX when possible. */
+	    }
 	  else
 	    {
 	      current_file = current_file->included_by;
@@ -751,7 +761,7 @@ dwarf_decode_macro_bytes (dwarf2_per_objfile *per_objfile,
 					  current_file, lh, section,
 					  section_is_gnu, is_dwz, offset_size,
 					  str_section, str_offsets_section,
-					  str_offsets_base, include_hash);
+					  str_offsets_base, include_hash, cu);
 
 		htab_remove_elt (include_hash, (void *) new_mac_ptr);
 	      }
@@ -795,7 +805,7 @@ dwarf_decode_macros (dwarf2_per_objfile *per_objfile,
 		     unsigned int offset, struct dwarf2_section_info *str_section,
 		     struct dwarf2_section_info *str_offsets_section,
 		     gdb::optional<ULONGEST> str_offsets_base,
-		     int section_is_gnu)
+		     int section_is_gnu, struct dwarf2_cu *cu)
 {
   bfd *abfd;
   const gdb_byte *mac_ptr, *mac_end;
@@ -956,5 +966,5 @@ dwarf_decode_macros (dwarf2_per_objfile *per_objfile,
   dwarf_decode_macro_bytes (per_objfile, builder, abfd, mac_ptr, mac_end,
 			    current_file, lh, section, section_is_gnu, 0,
 			    offset_size, str_section, str_offsets_section,
-			    str_offsets_base, include_hash.get ());
+			    str_offsets_base, include_hash.get (), cu);
 }
diff --git a/gdb/dwarf2/macro.h b/gdb/dwarf2/macro.h
index e8c33a34a8d..02753ef377a 100644
--- a/gdb/dwarf2/macro.h
+++ b/gdb/dwarf2/macro.h
@@ -31,6 +31,6 @@ extern void dwarf_decode_macros (dwarf2_per_objfile *per_objfile,
 				 dwarf2_section_info *str_section,
 				 dwarf2_section_info *str_offsets_section,
 				 gdb::optional<ULONGEST> str_offsets_base,
-				 int section_is_gnu);
+				 int section_is_gnu, struct dwarf2_cu *cu);
 
 #endif /* GDB_DWARF2_MACRO_H */
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 78f4cc1f60d..a0a46de61a6 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -9484,6 +9484,15 @@ producer_is_gcc_lt_4_3 (struct dwarf2_cu *cu)
   return cu->producer_is_gcc_lt_4_3;
 }
 
+bool
+producer_is_clang (struct dwarf2_cu *cu)
+{
+  if (!cu->checked_producer)
+    check_producer (cu);
+  
+  return cu->producer_is_clang;
+}
+
 static file_and_directory &
 find_file_and_directory (struct die_info *die, struct dwarf2_cu *cu)
 {
@@ -13343,6 +13352,10 @@ check_producer (struct dwarf2_cu *cu)
     }
   else if (startswith (cu->producer, "CodeWarrior S12/L-ISA"))
     cu->producer_is_codewarrior = true;
+  else if (producer_is_clang (cu->producer, &major, &minor))
+    {
+      cu->producer_is_clang = true;
+    }
   else
     {
       /* For other non-GCC compilers, expect their behavior is DWARF version
@@ -23363,7 +23376,7 @@ dwarf_decode_macros (struct dwarf2_cu *cu, unsigned int offset,
 
   dwarf_decode_macros (per_objfile, builder, section, lh,
 		       offset_size, offset, str_section, str_offsets_section,
-		       str_offsets_base, section_is_gnu);
+		       str_offsets_base, section_is_gnu, cu);
 }
 
 /* Return the .debug_loc section to use for CU.
diff --git a/gdb/dwarf2/read.h b/gdb/dwarf2/read.h
index 5f01fbc1025..a47e6bf5144 100644
--- a/gdb/dwarf2/read.h
+++ b/gdb/dwarf2/read.h
@@ -761,4 +761,6 @@ extern void dwarf2_get_section_info (struct objfile *,
 				     asection **, const gdb_byte **,
 				     bfd_size_type *);
 
+extern bool producer_is_clang (struct dwarf2_cu *cu);
+
 #endif /* DWARF2READ_H */
diff --git a/gdb/producer.c b/gdb/producer.c
index ef1dd93afbc..a9fb7dd8245 100644
--- a/gdb/producer.c
+++ b/gdb/producer.c
@@ -127,6 +127,32 @@ producer_is_llvm (const char *producer)
 				 || startswith (producer, " F90 Flang ")));
 }
 
+/* see producer.h */
+
+bool
+producer_is_clang (const char* producer, int *major, int* minor)
+{
+  const char *cs;
+
+  if (producer != nullptr && startswith (producer, "clang "))
+    {
+      int maj, min;
+      if (major == nullptr)
+	major = &maj;
+      if (minor == nullptr)
+	minor = &min;
+
+      /* The full producer sting will look something like
+	 "clang version XX.X.X ..."
+	 So we can safely ignore all characters before the first digit.  */
+      cs = producer + strlen("clang version ");
+
+      if (sscanf (cs, "%d.%d", major, minor) == 2)
+	  return true;
+    }
+  return false;
+}
+
 #if defined GDB_SELF_TEST
 namespace selftests {
 namespace producer {
diff --git a/gdb/producer.h b/gdb/producer.h
index f7c19368bc6..b75cfae6569 100644
--- a/gdb/producer.h
+++ b/gdb/producer.h
@@ -41,4 +41,8 @@ extern bool producer_is_icc (const char *producer, int *major, int *minor);
    false otherwise.*/
 extern bool producer_is_llvm (const char *producer);
 
+/* Returns true if the given PRODUCER string is clang, false otherwise.
+   Sets MAJOR and MINOR accordingly, if not NULL.  */
+extern bool producer_is_clang (const char *producer, int *major, int *minor);
+
 #endif
diff --git a/gdb/testsuite/gdb.dwarf2/clang_cli_macros.exp b/gdb/testsuite/gdb.dwarf2/clang_cli_macros.exp
new file mode 100644
index 00000000000..f056d8ad832
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/clang_cli_macros.exp
@@ -0,0 +1,101 @@
+# This testcase is part of GDB, the GNU debugger.
+
+# Copyright 2022 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Test that GDB is able to print macros defined in the command line invocaion
+# of clang. It has to be explicitly tested because of:
+# https://github.com/llvm/llvm-project/issues/54506
+
+load_lib dwarf.exp
+
+if {![dwarf2_support]} {
+    return 0
+}
+if {![test_compiler_info gcc-*-*]} {
+    untested "dwarf assembler needs GCC"
+}
+
+standard_testfile .S
+
+set srcfile macro-source-path.c
+set asm_file [standard_output_file clang_cli_macros.S]
+
+lassign [function_range main $srcdir/$subdir/$srcfile] \
+    main_start main_len
+
+Dwarf::assemble $asm_file {
+    global srcfile
+    declare_labels L cu_macros
+
+    cu {} {
+	DW_TAG_compile_unit {
+	    {DW_AT_producer "clang version 15.0.0"}
+	    {DW_AT_language @DW_LANG_C11}
+	    {DW_AT_name $srcfile}
+	    {DW_AT_macros $cu_macros DW_FORM_sec_offset}
+	    {DW_AT_stmt_list $L DW_FORM_sec_offset}
+	} {
+	    declare_labels int_type
+
+	    int_type: DW_TAG_base_type {
+	        {DW_AT_byte_size 4 DW_FORM_sdata}
+	        {DW_AT_encoding  @DW_ATE_signed}
+	        {DW_AT_name int}
+	    }
+	    DW_TAG_subprogram {
+	        {MACRO_AT_func {main}}
+	        {type :$int_type}
+	    }
+	}
+    }
+    lines {version 2} L {
+	file_name $srcfile 1
+	program {
+	    DW_LNE_set_address $::main_start
+	    line 10
+	    DW_LNS_copy
+	    DW_LNE_set_address "$::main_start + $::main_len"
+	    DW_LNE_end_sequence
+	}
+    }
+
+    # Define the .debug_macro section.
+    macro {
+	cu_macros: unit {
+	    "debug-line-offset-label" $L
+        } {
+	    # Clang has this bug where it puts the macros defined on
+	    # the command-line after the main file portion (see
+	    # PR 29034).
+	    start_file 0 1
+		# A macro defined at line 1 of the main file.
+		define 1 "TWO 2"
+	    end_file
+	    define 0 "ONE 1"
+	}
+    }
+}
+
+if {[prepare_for_testing "failed to prepare" $testfile [list $srcfile $asm_file] {nodebug}]} {
+    return
+}
+
+if {![runto_main]} {
+    return
+}
+
+gdb_test "print TWO" "= 2" "printing simple macro"
+gdb_test "print ONE" "= 1" "printing defined from CLI"
-- 
2.37.3


^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-10-17 15:28 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-10-17 10:26 [PATCH v2] gdb: Fix issue with Clang CLI macros Bruno Larsen
2022-10-17 12:32 ` Simon Marchi
2022-10-17 14:54   ` Bruno Larsen
2022-10-17 15:28     ` Simon Marchi
2022-10-17 13:22 ` Simon Marchi
2022-10-17 13:35   ` Bruno Larsen

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).