[PATCH] Fix DW_CFA_set_loc handling

[Jakub Jelinek]

On Tue, Sep 26, 2006 at 06:57:42AM -0700, H. J. Lu wrote:
> On Tue, Sep 26, 2006 at 02:38:40PM +0200, Jakub Jelinek wrote:
> > Hi!
> > 
> > Recent http://gcc.gnu.org/PR22313 change (including gcc 4.1 branch) started
> > (unnecessarily) using DW_CFA_set_loc at the start of all FDEs, but
> > unfortunately linker .eh_frame optimizations didn't handle that well.
> > If FDE encoding is pc relative or linker is changing it from absptr
> > to pc relative, we need to adjust the DW_CFA_set_loc operand accordingly.
> > 
> > Tested with make check on x86_64-linux, visual inspection of x86_64
> > readelf -wf libc.so.6 (this was seriously broken before) and visual
> > inspection of a hacked up test for absptr -> pcrel conversion.
> > 
> 
> Is that possible to include a testcase, even just for one arch/format?

Sure:

2006-09-26  Jakub Jelinek  <jakub@redhat.com>

	* ld-elf/eh4.d: New test.
	* ld-elf/eh4.s: New file.
	* ld-elf/eh4a.s: New file.

--- ld/testsuite/ld-elf/eh4.d.jj	2006-09-26 16:37:48.000000000 +0200
+++ ld/testsuite/ld-elf/eh4.d	2006-09-26 16:38:31.000000000 +0200
@@ -0,0 +1,32 @@
+#source: eh4.s
+#source: eh4a.s
+#ld: -shared
+#readelf: -wf
+#target: x86_64-*-*
+
+The section .eh_frame contains:
+
+00000000 00000014 00000000 CIE
+  Version:               1
+  Augmentation:          "zR"
+  Code alignment factor: 1
+  Data alignment factor: -8
+  Return address column: 16
+  Augmentation data:     1b
+
+  DW_CFA_def_cfa: r7 ofs 8
+  DW_CFA_offset: r16 at cfa-8
+  DW_CFA_nop
+  DW_CFA_nop
+
+00000018 00000014 0000001c FDE cie=00000000 pc=00000400..00000413
+  DW_CFA_set_loc: 00000404
+  DW_CFA_def_cfa_offset: 80
+
+00000030 00000014 00000034 FDE cie=00000000 pc=00000413..00000426
+  DW_CFA_set_loc: 00000417
+  DW_CFA_def_cfa_offset: 80
+
+00000048 ZERO terminator
+#pass
+
--- ld/testsuite/ld-elf/eh4.s.jj	2006-09-26 16:12:13.000000000 +0200
+++ ld/testsuite/ld-elf/eh4.s	2006-09-26 16:30:39.000000000 +0200
@@ -0,0 +1,92 @@
+	.text
+	.align	512
+	.globl foo
+	.type	foo, @function
+foo:
+.LFB1:
+	subq	$72, %rsp
+.LCFI1:
+	xorl	%eax, %eax
+	movq	%rsp, %rdi
+	call	bar@PLT
+	addq	$72, %rsp
+	ret
+.LFE1:
+	.size	foo, .-foo
+	.globl bar
+	.type	bar, @function
+bar:
+.LFB2:
+	subq	$72, %rsp
+.LCFI2:
+	xorl	%eax, %eax
+	movq	%rsp, %rdi
+	call	bar@PLT
+	addq	$72, %rsp
+	ret
+.LFE2:
+	.size	bar, .-bar
+	.section	.eh_frame,"a",@progbits
+.Lframe1:
+	.long	.LECIE1-.LSCIE1	# Length of Common Information Entry
+.LSCIE1:
+	.long	0x0	# CIE Identifier Tag
+	.byte	0x1	# CIE Version
+	.ascii "zR\0"	# CIE Augmentation
+	.uleb128 0x1	# CIE Code Alignment Factor
+	.sleb128 -8	# CIE Data Alignment Factor
+	.byte	0x10	# CIE RA Column
+	.uleb128 0x1	# Augmentation size
+	.byte	0x1b	# FDE Encoding (pcrel sdata4)
+	.byte	0xc	# DW_CFA_def_cfa
+	.uleb128 0x7
+	.uleb128 0x8
+	.byte	0x90	# DW_CFA_offset, column 0x10
+	.uleb128 0x1
+	.align 8
+.LECIE1:
+.LSFDE1:
+	.long	.LEFDE1-.LASFDE1	# FDE Length
+.LASFDE1:
+	.long	.LASFDE1-.Lframe1	# FDE CIE offset
+	.long	.LFB1-.	# FDE initial location
+	.long	.LFE1-.LFB1	# FDE address range
+	.uleb128 0x0	# Augmentation size
+	.byte	0x1	# DW_CFA_set_loc
+	.long	.LCFI1-.
+	.byte	0xe	# DW_CFA_def_cfa_offset
+	.uleb128 0x50
+	.align 8
+.LEFDE1:
+.Lframe2:
+	.long	.LECIE2-.LSCIE2	# Length of Common Information Entry
+.LSCIE2:
+	.long	0x0	# CIE Identifier Tag
+	.byte	0x1	# CIE Version
+	.ascii "zR\0"	# CIE Augmentation
+	.uleb128 0x1	# CIE Code Alignment Factor
+	.sleb128 -8	# CIE Data Alignment Factor
+	.byte	0x10	# CIE RA Column
+	.uleb128 0x1	# Augmentation size
+	.byte	0x1b	# FDE Encoding (pcrel sdata4)
+	.byte	0xc	# DW_CFA_def_cfa
+	.uleb128 0x7
+	.uleb128 0x8
+	.byte	0x90	# DW_CFA_offset, column 0x10
+	.uleb128 0x1
+	.align 8
+.LECIE2:
+.LSFDE2:
+	.long	.LEFDE2-.LASFDE2	# FDE Length
+.LASFDE2:
+	.long	.LASFDE2-.Lframe2	# FDE CIE offset
+	.long	.LFB2-.	# FDE initial location
+	.long	.LFE2-.LFB2	# FDE address range
+	.uleb128 0x0	# Augmentation size
+	.byte	0x1	# DW_CFA_set_loc
+	.long	.LCFI2-.
+	.byte	0xe	# DW_CFA_def_cfa_offset
+	.uleb128 0x50
+	.align 8
+.LEFDE2:
+	.section	.note.GNU-stack,"",@progbits
--- ld/testsuite/ld-elf/eh4a.s.jj	2006-09-26 16:39:07.000000000 +0200
+++ ld/testsuite/ld-elf/eh4a.s	2006-05-24 04:39:16.000000000 +0200
@@ -0,0 +1,3 @@
+	.section	.eh_frame,"a",%progbits
+	.align	8
+	.zero	8

	Jakub