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authorPedro Alves <palves@redhat.com>2015-07-24 14:57:20 +0100
committerPedro Alves <palves@redhat.com>2015-07-24 15:12:15 +0100
commit54019719152ab269fb4cec2c6a8a245ba6af6e49 (patch)
treed1252dcf1e0543ff063fde98919eaa8d55a05c0d /gdb/nat
parente379037592ff71dc633c6d3de0828babe805ae96 (diff)
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C++: handle glibc's ptrace(enum __ptrace_request, ...)
Building in C++ mode issues ~40 warnings like this: ../../src/gdb/linux-nat.c: In function ‘int linux_handle_extended_wait(lwp_info*, int, int)’: ../../src/gdb/linux-nat.c:2016:51: warning: invalid conversion from ‘int’ to ‘__ptrace_request’ [-fpermissive] ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid); The issue is that in glibc, ptrace's first parameter is an enum. That's not a problem if we pick the PTRACE_XXX requests from sys/ptrace.h, as those will be values of the corresponding enum. However, we have fallback definitions for PTRACE_XXX symbols when the system headers miss them (such as PTRACE_GETEVENTMSG above), and those are plain integer constants. E.g., nat/linux-ptrace.h: #define PTRACE_GETEVENTMSG 0x4201 One idea would be to fix this by defining those fallbacks like: -#define PTRACE_GETEVENTMSG 0x4201 +#define PTRACE_GETEVENTMSG ((enum __ptrace_request) 0x4201) However, while glibc's ptrace uses enum __ptrace_request for first parameter: extern long int ptrace (enum __ptrace_request __request, ...) __THROW; other libc's, like e.g., Android's bionic do not -- in that case, the first parameter is int: long ptrace(int request, pid_t pid, void * addr, void * data); So the fix I came up is to make configure/ptrace.m4 also detect the type of the ptrace's first parameter and defin PTRACE_TYPE_ARG1, as already does the for parameters 3-4, and then simply wrap ptrace with a macro that casts the first argument to the detected type. (I'm leaving adding a nicer wrapper for when we drop building in C). While this adds the wrapper, GNU/Linux files won't use it until the next patch, which makes all native GNU/Linux files include gdb_ptrace.h. gdb/ChangeLog: 2015-07-24 Pedro Alves <palves@redhat.com> * ptrace.m4 (ptrace tests): Test in C++ mode. Try with 'enum __ptrace_request as first parameter type instead of int. (PTRACE_TYPE_ARG1): Define. * nat/gdb_ptrace.h [!PTRACE_TYPE_ARG5] (ptrace): Define as wrapper that casts first argument to PTRACE_TYPE_ARG1. * config.in: Regenerate. * configure: Regenerate. gdb/gdbserver/ChangeLog: 2015-07-24 Pedro Alves <palves@redhat.com> * config.in: Regenerate. * configure: Regenerate.
Diffstat (limited to 'gdb/nat')
-rw-r--r--gdb/nat/gdb_ptrace.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/gdb/nat/gdb_ptrace.h b/gdb/nat/gdb_ptrace.h
index a969681..0a98239 100644
--- a/gdb/nat/gdb_ptrace.h
+++ b/gdb/nat/gdb_ptrace.h
@@ -144,6 +144,10 @@ extern PTRACE_TYPE_RET ptrace();
# define ptrace(request, pid, addr, data) \
ptrace (request, pid, addr, data, 0)
# endif
+#else
+/* Wrapper that avoids adding a pointless cast to all callers. */
+# define ptrace(request, pid, addr, data) \
+ ptrace ((PTRACE_TYPE_ARG1) request, pid, addr, data)
#endif
#endif /* gdb_ptrace.h */