PR28149, debug info with wrong file association

gcc-11 and gcc-12 pass -gdwarf-5 to gas, in order to prime gas for
DWARF 5 level debug info.  Unfortunately it seems there are cases
where the compiler does not emit a .file or .loc dwarf debug directive
before any machine instructions.  (Note that the .file directive
typically emitted as the first line of assembly output doesn't count as
a dwarf debug directive.  The dwarf .file has a file number before the
file name string.)

This patch delays allocation of file numbers for gas generated line
debug info until the end of assembly, thus avoiding any clashes with
compiler generated file numbers.  Two fixes for test case source are
necessary;  A .loc can't use a file number that hasn't already been
specified with .file.

A followup patch will remove all the gas generated line info on
seeing a .file directive.

	PR 28149
	* dwarf2dbg.c (num_of_auto_assigned): Delete.
	(current): Update initialisation.
	(set_or_check_view): Replace all accesses to view with u.view.
	(dwarf2_consume_line_info): Likewise.
	(dwarf2_directive_loc): Likewise.  Assert that we aren't generating
	line info.
	(dwarf2_gen_line_info_1): Don't call set_or_check_view on
	gas generated line entries.
	(dwarf2_gen_line_info): Set and track filenames for gas generated
	line entries.  Simplify generation of labels.
	(get_directory_table_entry): Use filename_cmp when comparing dirs.
	(do_allocate_filenum): New function.
	(dwarf2_where): Set u.filename and filenum to -1 for gas generated
	line entries.
	(dwarf2_directive_filename): Remove num_of_auto_assigned handling.
	(process_entries): Update view field access.  Call
	do_allocate_filenum.
	* dwarf2dbg.h (struct dwarf2_line_info): Add filename field in
	union aliasing view.
	* testsuite/gas/i386/dwarf2-line-3.s: Add .file directive.
	* testsuite/gas/i386/dwarf2-line-4.s: Likewise.
	* testsuite/gas/i386/dwarf2-line-4.d: Update expected output.
	* testsuite/gas/i386/dwarf4-line-1.d: Likewise.
	* testsuite/gas/i386/dwarf5-line-1.d: Likewise.
	* testsuite/gas/i386/dwarf5-line-2.d: Likewise.

6 files changed, 14 insertions, 4 deletions

diff --git a/gas/testsuite/gas/i386/dwarf2-line-3.s b/gas/testsuite/gas/i386/dwarf2-line-3.s
index 2085ef9..e933719 100644
--- a/gas/testsuite/gas/i386/dwarf2-line-3.s
+++ b/gas/testsuite/gas/i386/dwarf2-line-3.s
@@ -7,6 +7,7 @@
 main:
         .cfi_startproc
         nop
+	.file 1 "dwarf2-test.c"
 	.loc 1 1
         ret
         .cfi_endproc
diff --git a/gas/testsuite/gas/i386/dwarf2-line-4.d b/gas/testsuite/gas/i386/dwarf2-line-4.d
index c0c85f4..a01fd05 100644
--- a/gas/testsuite/gas/i386/dwarf2-line-4.d
+++ b/gas/testsuite/gas/i386/dwarf2-line-4.d
@@ -33,11 +33,14 @@ Raw dump of debug contents of section \.z?debug_line:
 
  The File Name Table \(offset 0x.*\):
   Entry	Dir	Time	Size	Name
-  1	1	0	0	dwarf2-line-4.s
+  1	0	0	0	dwarf2-test.c
+  2	1	0	0	dwarf2-line-4.s
 
  Line Number Statements:
+  \[0x.*\]  Set File Name to entry 2 in the File Name Table
   \[0x.*\]  Extended opcode 2: set Address to 0x0
   \[0x.*\]  Special opcode 13: advance Address by 0 to 0x0 and Line by 8 to 9
+  \[0x.*\]  Set File Name to entry 1 in the File Name Table
   \[0x.*\]  Advance Line by -8 to 1
   \[0x.*\]  Special opcode 19: advance Address by 1 to 0x1 and Line by 0 to 1
   \[0x.*\]  Advance PC by 1 to 0x2
diff --git a/gas/testsuite/gas/i386/dwarf2-line-4.s b/gas/testsuite/gas/i386/dwarf2-line-4.s
index 89bb62d..7348f4b 100644
--- a/gas/testsuite/gas/i386/dwarf2-line-4.s
+++ b/gas/testsuite/gas/i386/dwarf2-line-4.s
@@ -7,6 +7,7 @@
 main:
         .cfi_startproc
         nop
+	.file 1 "dwarf2-test.c"
 	.loc 1 1
         ret
         .cfi_endproc
diff --git a/gas/testsuite/gas/i386/dwarf4-line-1.d b/gas/testsuite/gas/i386/dwarf4-line-1.d
index 4f8321e..8199efb 100644
--- a/gas/testsuite/gas/i386/dwarf4-line-1.d
+++ b/gas/testsuite/gas/i386/dwarf4-line-1.d
@@ -36,12 +36,14 @@ Raw dump of debug contents of section \.z?debug_line:
   Entry	Dir	Time	Size	Name
   1	0	0	0	foo.c
   2	0	0	0	foo.h
+  3	1	0	0	dwarf4-line-1.s
 
  Line Number Statements:
+  \[0x.*\]  Set File Name to entry 2 in the File Name Table
   \[0x.*\]  Extended opcode 2: set Address to 0x0
   \[0x.*\]  Advance Line by 81 to 82
   \[0x.*\]  Copy
-  \[0x.*\]  Set File Name to entry 2 in the File Name Table
+  \[0x.*\]  Set File Name to entry 3 in the File Name Table
   \[0x.*\]  Advance Line by -73 to 9
   \[0x.*\]  Special opcode 19: advance Address by 1 to 0x1 and Line by 0 to 9
   \[0x.*\]  Advance PC by 3 to 0x4
diff --git a/gas/testsuite/gas/i386/dwarf5-line-1.d b/gas/testsuite/gas/i386/dwarf5-line-1.d
index f57fc47..2c2cf56 100644
--- a/gas/testsuite/gas/i386/dwarf5-line-1.d
+++ b/gas/testsuite/gas/i386/dwarf5-line-1.d
@@ -36,12 +36,14 @@ Raw dump of debug contents of section \.z?debug_line:
   0	\(indirect line string, offset: 0x.*\): .*/gas/testsuite
   1	\(indirect line string, offset: 0x.*\): .*/gas/testsuite/gas/i386
 
- The File Name Table \(offset 0x.*, lines 2, columns 3\):
+ The File Name Table \(offset 0x.*, lines 3, columns 3\):
   Entry	Dir	MD5				Name
   0	0 0xbbd69fc03ce253b2dbaab2522dd519ae	\(indirect line string, offset: 0x.*\): core.c
   1	0 0x0	\(indirect line string, offset: 0x.*\): types.h
+  2	1 0x0	\(indirect line string, offset: 0x.*\): dwarf5-line-1.s
 
  Line Number Statements:
+  \[0x.*\]  Set File Name to entry 2 in the File Name Table
   \[0x.*\]  Extended opcode 2: set Address to 0x0
   \[0x.*\]  Special opcode 8: advance Address by 0 to 0x0 and Line by 3 to 4
   \[0x.*\]  Advance PC by 1 to 0x1
diff --git a/gas/testsuite/gas/i386/dwarf5-line-2.d b/gas/testsuite/gas/i386/dwarf5-line-2.d
index 2f96df5..85f98c8 100644
--- a/gas/testsuite/gas/i386/dwarf5-line-2.d
+++ b/gas/testsuite/gas/i386/dwarf5-line-2.d
@@ -36,9 +36,10 @@ Raw dump of debug contents of section \.z?debug_line:
   0	\(indirect line string, offset: 0x.*\): .*/gas/testsuite
   1	\(indirect line string, offset: 0x.*\): .*/gas/testsuite/gas/i386
 
- The File Name Table \(offset 0x.*, lines 1, columns 3\):
+ The File Name Table \(offset 0x.*, lines 2, columns 3\):
   Entry	Dir	MD5				Name
   0	0 0xbbd69fc03ce253b2dbaab2522dd519ae	\(indirect line string, offset: 0x.*\): core.c
+  1	1 0x0	\(indirect line string, offset: .*\): dwarf5-line-2.s
 
  Line Number Statements:
   \[0x.*\]  Extended opcode 2: set Address to 0x0