* [PATCH] bpf: set PREFERRED_DEBUGGING_TYPE to BTF_DEBUG
@ 2024-04-25 17:23 David Faust
2024-04-25 18:45 ` Jose E. Marchesi
0 siblings, 1 reply; 2+ messages in thread
From: David Faust @ 2024-04-25 17:23 UTC (permalink / raw)
To: gcc-patches; +Cc: jose.marchesi
BTF is the standard debug info used with BPF programs, so it makes sense
to default to BTF rather than DWARF.
Tested on x86_64-linux-gnu host for bpf-unknown-none target.
gcc/
* config/bpf/bpf.h (PREFERRED_DEBUGGING_TYPE): Set to BTF_DEBUG.
gcc/testsuite/
* gcc.target/bpf/bpf-debug-options-1.c: New test.
* gcc.target/bpf/bpf-debug-options-2.c: Likewise.
* gcc.target/bpf/bpf-debug-options-3.c: Likewise.
* gcc.target/bpf/core-options-4.c: Likewise.
---
gcc/config/bpf/bpf.h | 5 +++++
.../gcc.target/bpf/bpf-debug-options-1.c | 17 +++++++++++++++++
.../gcc.target/bpf/bpf-debug-options-2.c | 18 ++++++++++++++++++
.../gcc.target/bpf/bpf-debug-options-3.c | 14 ++++++++++++++
gcc/testsuite/gcc.target/bpf/core-options-4.c | 4 ++++
5 files changed, 58 insertions(+)
create mode 100644 gcc/testsuite/gcc.target/bpf/bpf-debug-options-1.c
create mode 100644 gcc/testsuite/gcc.target/bpf/bpf-debug-options-2.c
create mode 100644 gcc/testsuite/gcc.target/bpf/bpf-debug-options-3.c
create mode 100644 gcc/testsuite/gcc.target/bpf/core-options-4.c
diff --git a/gcc/config/bpf/bpf.h b/gcc/config/bpf/bpf.h
index c67e17526bf..e163fbf688d 100644
--- a/gcc/config/bpf/bpf.h
+++ b/gcc/config/bpf/bpf.h
@@ -245,6 +245,11 @@ enum reg_class
/**** Debugging Info ****/
+/* Use BTF debug info by default. */
+
+#undef PREFERRED_DEBUGGING_TYPE
+#define PREFERRED_DEBUGGING_TYPE BTF_DEBUG
+
/* In eBPF it is not possible to unwind frames. Disable CFA. */
#define DWARF2_FRAME_INFO 0
diff --git a/gcc/testsuite/gcc.target/bpf/bpf-debug-options-1.c b/gcc/testsuite/gcc.target/bpf/bpf-debug-options-1.c
new file mode 100644
index 00000000000..409466c4ead
--- /dev/null
+++ b/gcc/testsuite/gcc.target/bpf/bpf-debug-options-1.c
@@ -0,0 +1,17 @@
+/* Default to BTF debug info. */
+/* { dg-do compile } */
+/* { dg-options "-g -dA" }*/
+
+struct A {
+ int x;
+ int y;
+};
+
+int
+foo (struct A *a)
+{
+ return a->x;
+}
+
+/* { dg-final { scan-assembler-not "DWARF version" } } */
+/* { dg-final { scan-assembler "btf_version" } } */
diff --git a/gcc/testsuite/gcc.target/bpf/bpf-debug-options-2.c b/gcc/testsuite/gcc.target/bpf/bpf-debug-options-2.c
new file mode 100644
index 00000000000..03bde12315b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/bpf/bpf-debug-options-2.c
@@ -0,0 +1,18 @@
+/* -g defaults to BTF, which in turn implies -mco-re. */
+/* { dg-do compile } */
+/* { dg-options "-g -dA" }*/
+
+struct A {
+ int x;
+ int y;
+};
+
+int
+foo (struct A *a)
+{
+ return __builtin_preserve_access_index (a->x);
+}
+
+/* { dg-final { scan-assembler-not "DWARF version" } } */
+/* { dg-final { scan-assembler "btf_version" } } */
+/* { dg-final { scan-assembler "btfext_version" } } */
diff --git a/gcc/testsuite/gcc.target/bpf/bpf-debug-options-3.c b/gcc/testsuite/gcc.target/bpf/bpf-debug-options-3.c
new file mode 100644
index 00000000000..d41790e0928
--- /dev/null
+++ b/gcc/testsuite/gcc.target/bpf/bpf-debug-options-3.c
@@ -0,0 +1,14 @@
+/* Using -g does not incorrectly force CO-RE enabled. */
+/* { dg-do compile } */
+/* { dg-options "-g -dA -mno-co-re" }*/
+
+struct A {
+ int x;
+ int y;
+};
+
+int
+foo (struct A *a)
+{
+ return __builtin_preserve_access_index (a->x); /* { dg-error "BPF CO-RE is required" } */
+}
diff --git a/gcc/testsuite/gcc.target/bpf/core-options-4.c b/gcc/testsuite/gcc.target/bpf/core-options-4.c
new file mode 100644
index 00000000000..fde4195da42
--- /dev/null
+++ b/gcc/testsuite/gcc.target/bpf/core-options-4.c
@@ -0,0 +1,4 @@
+/* -g implies BTF, -gtoggle turns it off. CO-RE should not work. */
+/* { dg-do compile } */
+/* { dg-options "-g -mco-re -gtoggle" } */
+/* { dg-excess-errors "BPF CO-RE requires BTF debugging information" } */
--
2.43.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] bpf: set PREFERRED_DEBUGGING_TYPE to BTF_DEBUG
2024-04-25 17:23 [PATCH] bpf: set PREFERRED_DEBUGGING_TYPE to BTF_DEBUG David Faust
@ 2024-04-25 18:45 ` Jose E. Marchesi
0 siblings, 0 replies; 2+ messages in thread
From: Jose E. Marchesi @ 2024-04-25 18:45 UTC (permalink / raw)
To: David Faust; +Cc: gcc-patches
Hi David.
OK. Thanks for the patch.
> BTF is the standard debug info used with BPF programs, so it makes sense
> to default to BTF rather than DWARF.
>
> Tested on x86_64-linux-gnu host for bpf-unknown-none target.
>
> gcc/
> * config/bpf/bpf.h (PREFERRED_DEBUGGING_TYPE): Set to BTF_DEBUG.
>
> gcc/testsuite/
> * gcc.target/bpf/bpf-debug-options-1.c: New test.
> * gcc.target/bpf/bpf-debug-options-2.c: Likewise.
> * gcc.target/bpf/bpf-debug-options-3.c: Likewise.
> * gcc.target/bpf/core-options-4.c: Likewise.
> ---
> gcc/config/bpf/bpf.h | 5 +++++
> .../gcc.target/bpf/bpf-debug-options-1.c | 17 +++++++++++++++++
> .../gcc.target/bpf/bpf-debug-options-2.c | 18 ++++++++++++++++++
> .../gcc.target/bpf/bpf-debug-options-3.c | 14 ++++++++++++++
> gcc/testsuite/gcc.target/bpf/core-options-4.c | 4 ++++
> 5 files changed, 58 insertions(+)
> create mode 100644 gcc/testsuite/gcc.target/bpf/bpf-debug-options-1.c
> create mode 100644 gcc/testsuite/gcc.target/bpf/bpf-debug-options-2.c
> create mode 100644 gcc/testsuite/gcc.target/bpf/bpf-debug-options-3.c
> create mode 100644 gcc/testsuite/gcc.target/bpf/core-options-4.c
>
> diff --git a/gcc/config/bpf/bpf.h b/gcc/config/bpf/bpf.h
> index c67e17526bf..e163fbf688d 100644
> --- a/gcc/config/bpf/bpf.h
> +++ b/gcc/config/bpf/bpf.h
> @@ -245,6 +245,11 @@ enum reg_class
>
> /**** Debugging Info ****/
>
> +/* Use BTF debug info by default. */
> +
> +#undef PREFERRED_DEBUGGING_TYPE
> +#define PREFERRED_DEBUGGING_TYPE BTF_DEBUG
> +
> /* In eBPF it is not possible to unwind frames. Disable CFA. */
>
> #define DWARF2_FRAME_INFO 0
> diff --git a/gcc/testsuite/gcc.target/bpf/bpf-debug-options-1.c b/gcc/testsuite/gcc.target/bpf/bpf-debug-options-1.c
> new file mode 100644
> index 00000000000..409466c4ead
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/bpf-debug-options-1.c
> @@ -0,0 +1,17 @@
> +/* Default to BTF debug info. */
> +/* { dg-do compile } */
> +/* { dg-options "-g -dA" }*/
> +
> +struct A {
> + int x;
> + int y;
> +};
> +
> +int
> +foo (struct A *a)
> +{
> + return a->x;
> +}
> +
> +/* { dg-final { scan-assembler-not "DWARF version" } } */
> +/* { dg-final { scan-assembler "btf_version" } } */
> diff --git a/gcc/testsuite/gcc.target/bpf/bpf-debug-options-2.c b/gcc/testsuite/gcc.target/bpf/bpf-debug-options-2.c
> new file mode 100644
> index 00000000000..03bde12315b
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/bpf-debug-options-2.c
> @@ -0,0 +1,18 @@
> +/* -g defaults to BTF, which in turn implies -mco-re. */
> +/* { dg-do compile } */
> +/* { dg-options "-g -dA" }*/
> +
> +struct A {
> + int x;
> + int y;
> +};
> +
> +int
> +foo (struct A *a)
> +{
> + return __builtin_preserve_access_index (a->x);
> +}
> +
> +/* { dg-final { scan-assembler-not "DWARF version" } } */
> +/* { dg-final { scan-assembler "btf_version" } } */
> +/* { dg-final { scan-assembler "btfext_version" } } */
> diff --git a/gcc/testsuite/gcc.target/bpf/bpf-debug-options-3.c b/gcc/testsuite/gcc.target/bpf/bpf-debug-options-3.c
> new file mode 100644
> index 00000000000..d41790e0928
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/bpf-debug-options-3.c
> @@ -0,0 +1,14 @@
> +/* Using -g does not incorrectly force CO-RE enabled. */
> +/* { dg-do compile } */
> +/* { dg-options "-g -dA -mno-co-re" }*/
> +
> +struct A {
> + int x;
> + int y;
> +};
> +
> +int
> +foo (struct A *a)
> +{
> + return __builtin_preserve_access_index (a->x); /* { dg-error "BPF CO-RE is required" } */
> +}
> diff --git a/gcc/testsuite/gcc.target/bpf/core-options-4.c b/gcc/testsuite/gcc.target/bpf/core-options-4.c
> new file mode 100644
> index 00000000000..fde4195da42
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/core-options-4.c
> @@ -0,0 +1,4 @@
> +/* -g implies BTF, -gtoggle turns it off. CO-RE should not work. */
> +/* { dg-do compile } */
> +/* { dg-options "-g -mco-re -gtoggle" } */
> +/* { dg-excess-errors "BPF CO-RE requires BTF debugging information" } */
^ permalink raw reply [flat|nested] 2+ messages in thread
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2024-04-25 18:45 ` Jose E. Marchesi
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