[Buildroot] [PATCH] gdb: add fix for gdb 7.12 and gdb 8.0 build on noMMU platforms

[Romain Naour]

Hi Thomas,

Le 03/08/2017 à 09:15, Thomas Petazzoni a écrit :
> This adds a patch to gdb 7.12 and gdb 8.x, which fixes the build on
> noMMU platforms. It is not needed for older versions of gdb, since
> it's related to the switch of gdb to C++ in the 7.12 release.
> 
> Fixes:
> 
> ../nat/linux-ptrace.c: In function 'int linux_fork_to_function(gdb_byte*, int (*)(void*))':
> ../nat/linux-ptrace.c:273:29: error: invalid conversion from 'void*' to 'gdb_byte* {aka unsigned char*}' [-fpermissive]
>        child_stack = xmalloc (STACK_SIZE * 4);
> 
> The patch has already been merged upstream, as of commit
> ffce45d2243e5f52f411e314fc4e1a69f431a81f, and will therefore be part
> of future gdb releases.

What's the arch/config are you using?
It's seems no toolchain able to build gdb on noMMU case are present in the
autobuilder.

Best regards,
Romain

> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
> ---
>  ...-linux-ptrace.c-add-missing-gdb_byte-cast.patch | 41 ++++++++++++++++++++++
>  ...-linux-ptrace.c-add-missing-gdb_byte-cast.patch | 41 ++++++++++++++++++++++
>  2 files changed, 82 insertions(+)
>  create mode 100644 package/gdb/7.12.1/0006-nat-linux-ptrace.c-add-missing-gdb_byte-cast.patch
>  create mode 100644 package/gdb/8.0/0004-nat-linux-ptrace.c-add-missing-gdb_byte-cast.patch
> 
> diff --git a/package/gdb/7.12.1/0006-nat-linux-ptrace.c-add-missing-gdb_byte-cast.patch b/package/gdb/7.12.1/0006-nat-linux-ptrace.c-add-missing-gdb_byte-cast.patch
> new file mode 100644
> index 0000000..4eb72e4
> --- /dev/null
> +++ b/package/gdb/7.12.1/0006-nat-linux-ptrace.c-add-missing-gdb_byte-cast.patch
> @@ -0,0 +1,41 @@
> +From 09a2c3e0164545324a1ddee70f5c9fdee71e2079 Mon Sep 17 00:00:00 2001
> +From: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
> +Date: Sun, 18 Jun 2017 23:09:43 +0200
> +Subject: [PATCH] nat/linux-ptrace.c: add missing gdb_byte* cast
> +
> +On noMMU platforms, the following code gets compiled:
> +
> +  child_stack = xmalloc (STACK_SIZE * 4);
> +
> +Where child_stack is a gdb_byte*, and xmalloc() returns a void*. While
> +the lack of cast is valid in C, it is not in C++, causing the
> +following build failure:
> +
> +../nat/linux-ptrace.c: In function 'int linux_fork_to_function(gdb_byte*, int (*)(void*))':
> +../nat/linux-ptrace.c:273:29: error: invalid conversion from 'void*' to 'gdb_byte* {aka unsigned char*}' [-fpermissive]
> +       child_stack = xmalloc (STACK_SIZE * 4);
> +
> +Therefore, this commit adds the appropriate cast.
> +
> +Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
> +[Upstream commit: ffce45d2243e5f52f411e314fc4e1a69f431a81f]
> +---
> + gdb/nat/linux-ptrace.c | 2 +-
> + 1 file changed, 1 insertion(+), 1 deletion(-)
> +
> +diff --git a/gdb/nat/linux-ptrace.c b/gdb/nat/linux-ptrace.c
> +index 3447e07..33833e2 100644
> +--- a/gdb/nat/linux-ptrace.c
> ++++ b/gdb/nat/linux-ptrace.c
> +@@ -270,7 +270,7 @@ linux_fork_to_function (gdb_byte *child_stack, int (*function) (void *))
> + #define STACK_SIZE 4096
> + 
> +     if (child_stack == NULL)
> +-      child_stack = xmalloc (STACK_SIZE * 4);
> ++      child_stack = (gdb_byte*) xmalloc (STACK_SIZE * 4);
> + 
> +     /* Use CLONE_VM instead of fork, to support uClinux (no MMU).  */
> + #ifdef __ia64__
> +-- 
> +2.9.4
> +
> diff --git a/package/gdb/8.0/0004-nat-linux-ptrace.c-add-missing-gdb_byte-cast.patch b/package/gdb/8.0/0004-nat-linux-ptrace.c-add-missing-gdb_byte-cast.patch
> new file mode 100644
> index 0000000..4eb72e4
> --- /dev/null
> +++ b/package/gdb/8.0/0004-nat-linux-ptrace.c-add-missing-gdb_byte-cast.patch
> @@ -0,0 +1,41 @@
> +From 09a2c3e0164545324a1ddee70f5c9fdee71e2079 Mon Sep 17 00:00:00 2001
> +From: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
> +Date: Sun, 18 Jun 2017 23:09:43 +0200
> +Subject: [PATCH] nat/linux-ptrace.c: add missing gdb_byte* cast
> +
> +On noMMU platforms, the following code gets compiled:
> +
> +  child_stack = xmalloc (STACK_SIZE * 4);
> +
> +Where child_stack is a gdb_byte*, and xmalloc() returns a void*. While
> +the lack of cast is valid in C, it is not in C++, causing the
> +following build failure:
> +
> +../nat/linux-ptrace.c: In function 'int linux_fork_to_function(gdb_byte*, int (*)(void*))':
> +../nat/linux-ptrace.c:273:29: error: invalid conversion from 'void*' to 'gdb_byte* {aka unsigned char*}' [-fpermissive]
> +       child_stack = xmalloc (STACK_SIZE * 4);
> +
> +Therefore, this commit adds the appropriate cast.
> +
> +Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
> +[Upstream commit: ffce45d2243e5f52f411e314fc4e1a69f431a81f]
> +---
> + gdb/nat/linux-ptrace.c | 2 +-
> + 1 file changed, 1 insertion(+), 1 deletion(-)
> +
> +diff --git a/gdb/nat/linux-ptrace.c b/gdb/nat/linux-ptrace.c
> +index 3447e07..33833e2 100644
> +--- a/gdb/nat/linux-ptrace.c
> ++++ b/gdb/nat/linux-ptrace.c
> +@@ -270,7 +270,7 @@ linux_fork_to_function (gdb_byte *child_stack, int (*function) (void *))
> + #define STACK_SIZE 4096
> + 
> +     if (child_stack == NULL)
> +-      child_stack = xmalloc (STACK_SIZE * 4);
> ++      child_stack = (gdb_byte*) xmalloc (STACK_SIZE * 4);
> + 
> +     /* Use CLONE_VM instead of fork, to support uClinux (no MMU).  */
> + #ifdef __ia64__
> +-- 
> +2.9.4
> +
>