[v1,1/4] aarch64: make explicit that CFI gnu_window_save is for Sparc, not AArch64
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Commit Message
- add a detailed comment when parsing DW_CFA_GNU_window_save in SFrame to
explain why we are checking whether the targeted architecture is AArch64,
whereas this CFI is a Sparc extension.
- replace .cfi_gnu_window_save by .cfi_negate_ra_state in existing AArch64
DWARF tests as this is the preferred directive since GCC 15.
- add a new AARch64 test to check backward compatibility with old GCC
versions that emits .cfi_gnu_window_save.
---
gas/gen-sframe.c | 8 +++++-
gas/testsuite/gas/aarch64/pac_ab_key.s | 4 +--
.../gas/aarch64/pac_compat_cfi_window_save.d | 26 +++++++++++++++++++
.../gas/aarch64/pac_compat_cfi_window_save.s | 20 ++++++++++++++
4 files changed, 55 insertions(+), 3 deletions(-)
create mode 100644 gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.d
create mode 100644 gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.s
Comments
On 11/25/24 8:28 AM, Matthieu Longo wrote:
> - add a detailed comment when parsing DW_CFA_GNU_window_save in SFrame to
> explain why we are checking whether the targeted architecture is AArch64,
> whereas this CFI is a Sparc extension.
> - replace .cfi_gnu_window_save by .cfi_negate_ra_state in existing AArch64
> DWARF tests as this is the preferred directive since GCC 15.
> - add a new AARch64 test to check backward compatibility with old GCC
> versions that emits .cfi_gnu_window_save.
> ---
> gas/gen-sframe.c | 8 +++++-
> gas/testsuite/gas/aarch64/pac_ab_key.s | 4 +--
> .../gas/aarch64/pac_compat_cfi_window_save.d | 26 +++++++++++++++++++
> .../gas/aarch64/pac_compat_cfi_window_save.s | 20 ++++++++++++++
> 4 files changed, 55 insertions(+), 3 deletions(-)
> create mode 100644 gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.d
> create mode 100644 gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.s
>
> diff --git a/gas/gen-sframe.c b/gas/gen-sframe.c
> index 626dc33b71d..be48b339609 100644
> --- a/gas/gen-sframe.c
> +++ b/gas/gen-sframe.c
> @@ -1283,7 +1283,13 @@ sframe_xlate_do_aarch64_negate_ra_state (struct sframe_xlate_ctx *xlate_ctx,
> }
>
> /* Translate DW_CFA_GNU_window_save into SFrame context.
> - DW_CFA_AARCH64_negate_ra_state is multiplexed with DW_CFA_GNU_window_save.
> + DW_CFA_GNU_window_save is a DWARF Sparc extension, but is multiplexed with a
> + directive of DWARF AArch64 extension: DW_CFA_AARCH64_negate_ra_state.
> + The AArch64 backend of GCC 14 and older versions was emitting mistakenly the
> + Sparc CFI directive (.cfi_window_save). From GCC 15, the AArch64 backend only
> + emits .cfi_negate_ra_state. For backward compatibility, the handler for
> + .cfi_window_save needs to check whether the directive was used in a AArch ABI
> + context or not.
Nit: There are a few "dot, space, space, new sentence" issues in the
comment block above.
The patch looks OK to me otherwise,
Thanks
Indu
> Return SFRAME_XLATE_OK if success. */
>
> static int
> diff --git a/gas/testsuite/gas/aarch64/pac_ab_key.s b/gas/testsuite/gas/aarch64/pac_ab_key.s
> index 4b328e72ae4..3b81919409d 100644
> --- a/gas/testsuite/gas/aarch64/pac_ab_key.s
> +++ b/gas/testsuite/gas/aarch64/pac_ab_key.s
> @@ -7,7 +7,7 @@ _Z5foo_av:
> .LFB0:
> .cfi_startproc
> hint 25 // paciasp
> - .cfi_window_save
> + .cfi_negate_ra_state
> stp x29, x30, [sp, -16]!
> .cfi_def_cfa_offset 16
> .cfi_offset 29, -16
> @@ -23,7 +23,7 @@ _Z5foo_bv:
> .cfi_startproc
> .cfi_b_key_frame
> hint 27 // pacibsp
> - .cfi_window_save
> + .cfi_negate_ra_state
> stp x29, x30, [sp, -16]!
> .cfi_def_cfa_offset 16
> .cfi_offset 29, -16
> diff --git a/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.d b/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.d
> new file mode 100644
> index 00000000000..f49cebcbfde
> --- /dev/null
> +++ b/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.d
> @@ -0,0 +1,26 @@
> +#objdump: --dwarf=frames
> +# This test is only valid on ELF based ports.
> +#notarget: *-*-*coff *-*-pe *-*-wince *-*-*aout* *-*-netbsd
> +
> +.+: file .+
> +
> +Contents of the .eh_frame section:
> +
> +0+ 0+10 0+ CIE
> + Version: 1
> + Augmentation: "zR"
> + Code alignment factor: 4
> + Data alignment factor: -8
> + Return address column: 30
> + Augmentation data: 1b
> + DW_CFA_def_cfa: r31 \(sp\) ofs 0
> +
> +0+14 0+18 0+18 FDE cie=0+ pc=0+\.\.0+8
> + DW_CFA_advance_loc: 4 to 0+4
> + DW_CFA_AARCH64_negate_ra_state
> + DW_CFA_advance_loc: 4 to 0+8
> + DW_CFA_def_cfa_offset: 16
> + DW_CFA_offset: r29 \(x29\) at cfa-16
> + DW_CFA_offset: r30 \(x30\) at cfa-8
> + DW_CFA_nop
> + DW_CFA_nop
> diff --git a/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.s b/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.s
> new file mode 100644
> index 00000000000..1bfdef71f22
> --- /dev/null
> +++ b/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.s
> @@ -0,0 +1,20 @@
> + .arch armv8-a
> + .text
> + .align 2
> + .global _Z5foo_av
> + .type _Z5foo_av, %function
> +_Z5foo_av:
> +.LFB0:
> + .cfi_startproc
> + hint 25 // paciasp
> + .cfi_window_save
> + stp x29, x30, [sp, -16]!
> + .cfi_def_cfa_offset 16
> + .cfi_offset 29, -16
> + .cfi_offset 30, -8
> + .cfi_endproc
> +.LFE0:
> + .size _Z5foo_av, .-_Z5foo_av
> + .align 2
> + .global _Z5foo_bv
> + .type _Z5foo_bv, %function
@@ -1283,7 +1283,13 @@ sframe_xlate_do_aarch64_negate_ra_state (struct sframe_xlate_ctx *xlate_ctx,
}
/* Translate DW_CFA_GNU_window_save into SFrame context.
- DW_CFA_AARCH64_negate_ra_state is multiplexed with DW_CFA_GNU_window_save.
+ DW_CFA_GNU_window_save is a DWARF Sparc extension, but is multiplexed with a
+ directive of DWARF AArch64 extension: DW_CFA_AARCH64_negate_ra_state.
+ The AArch64 backend of GCC 14 and older versions was emitting mistakenly the
+ Sparc CFI directive (.cfi_window_save). From GCC 15, the AArch64 backend only
+ emits .cfi_negate_ra_state. For backward compatibility, the handler for
+ .cfi_window_save needs to check whether the directive was used in a AArch ABI
+ context or not.
Return SFRAME_XLATE_OK if success. */
static int
@@ -7,7 +7,7 @@ _Z5foo_av:
.LFB0:
.cfi_startproc
hint 25 // paciasp
- .cfi_window_save
+ .cfi_negate_ra_state
stp x29, x30, [sp, -16]!
.cfi_def_cfa_offset 16
.cfi_offset 29, -16
@@ -23,7 +23,7 @@ _Z5foo_bv:
.cfi_startproc
.cfi_b_key_frame
hint 27 // pacibsp
- .cfi_window_save
+ .cfi_negate_ra_state
stp x29, x30, [sp, -16]!
.cfi_def_cfa_offset 16
.cfi_offset 29, -16
new file mode 100644
@@ -0,0 +1,26 @@
+#objdump: --dwarf=frames
+# This test is only valid on ELF based ports.
+#notarget: *-*-*coff *-*-pe *-*-wince *-*-*aout* *-*-netbsd
+
+.+: file .+
+
+Contents of the .eh_frame section:
+
+0+ 0+10 0+ CIE
+ Version: 1
+ Augmentation: "zR"
+ Code alignment factor: 4
+ Data alignment factor: -8
+ Return address column: 30
+ Augmentation data: 1b
+ DW_CFA_def_cfa: r31 \(sp\) ofs 0
+
+0+14 0+18 0+18 FDE cie=0+ pc=0+\.\.0+8
+ DW_CFA_advance_loc: 4 to 0+4
+ DW_CFA_AARCH64_negate_ra_state
+ DW_CFA_advance_loc: 4 to 0+8
+ DW_CFA_def_cfa_offset: 16
+ DW_CFA_offset: r29 \(x29\) at cfa-16
+ DW_CFA_offset: r30 \(x30\) at cfa-8
+ DW_CFA_nop
+ DW_CFA_nop
new file mode 100644
@@ -0,0 +1,20 @@
+ .arch armv8-a
+ .text
+ .align 2
+ .global _Z5foo_av
+ .type _Z5foo_av, %function
+_Z5foo_av:
+.LFB0:
+ .cfi_startproc
+ hint 25 // paciasp
+ .cfi_window_save
+ stp x29, x30, [sp, -16]!
+ .cfi_def_cfa_offset 16
+ .cfi_offset 29, -16
+ .cfi_offset 30, -8
+ .cfi_endproc
+.LFE0:
+ .size _Z5foo_av, .-_Z5foo_av
+ .align 2
+ .global _Z5foo_bv
+ .type _Z5foo_bv, %function