Reviewers: Yang, ulan, danno, Sven Panne,
Message:
Thanks, just got back from vacation, will work on it.
Description:
android: refine custom ucontext_t definitions.
This is a forward-compatible change to avoid type/naming
conflicts when the Android platform/NDK will update its
<signal.h> header to properly define 'struct sigcontext',
'mcontext_t' and 'ucontext_t'.
In particular:
- Do not define 'struct sigcontext.h' to avoid
conflicts with the C library definition (which
is different, see below).
- Only provide custom ucontext_t declarations if
the Android <signal.h> doesn't provide it. This can
be tested with a macro check (__BIONIC_HAVE_UCONTEXT_T)
+ Use 'gettid()' on Android since it is available (at all
API levels).
BUG=
TEST=
Please review this at https://chromiumcodereview.appspot.com/10690163/
SVN Base: git://github.com/v8/v8.git@master
Affected files:
M src/platform-linux.cc
Index: src/platform-linux.cc
diff --git a/src/platform-linux.cc b/src/platform-linux.cc
index
9028fd0238a9d5b1cae6672c7cb10cf77c05046a..08a52a2241583b3fb00f4ef4ffca41689f939d6b
100644
--- a/src/platform-linux.cc
+++ b/src/platform-linux.cc
@@ -904,32 +904,36 @@ Semaphore* OS::CreateSemaphore(int count) {
}
-#if !defined(__GLIBC__) && (defined(__arm__) || defined(__thumb__))
-// Android runs a fairly new Linux kernel, so signal info is there,
-// but the C library doesn't have the structs defined.
+#if defined(__ANDROID__) && !defined(__BIONIC_HAVE_UCONTEXT_T)
+
+// Not all versions of Android's C library provide ucontext_t.
+// Detect this and provide custom but compatible definitions. Note that
these
+// follow the GLibc naming convention to access register values from
+// mcontext_t.
+
+#if defined(__arm__) || defined(__thumb__) || defined(__thumb2__)
+
+// GLibc on ARM defines mcontext_t has a typedef for 'struct sigcontext'.
+// Old versions of the C library <signal.h> didn't define the type.
+#if !defined(__BIONIC_HAVE_STRUCT_SIGCONTEXT)
+#include <asm/sigcontext.h>
+#endif
-struct sigcontext {
- uint32_t trap_no;
- uint32_t error_code;
- uint32_t oldmask;
- uint32_t gregs[16];
- uint32_t arm_cpsr;
- uint32_t fault_address;
-};
-typedef uint32_t __sigset_t;
typedef struct sigcontext mcontext_t;
+
+typedef uint32_t kernel_sigset_t[2]; // ARM kernel uses 64-bit signal
masks
+
typedef struct ucontext {
uint32_t uc_flags;
struct ucontext* uc_link;
stack_t uc_stack;
mcontext_t uc_mcontext;
- __sigset_t uc_sigmask;
+ kernel_sigset_t uc_sigmask;
} ucontext_t;
-enum ArmRegisters {R15 = 15, R13 = 13, R11 = 11};
-#elif !defined(__GLIBC__) && defined(__mips__)
+#elif defined(__mips__)
// MIPS version of sigcontext, for Android bionic.
-struct sigcontext {
+typedef struct {
uint32_t regmask;
uint32_t status;
uint64_t pc;
@@ -948,44 +952,44 @@ struct sigcontext {
uint32_t lo2;
uint32_t hi3;
uint32_t lo3;
-};
-typedef uint32_t __sigset_t;
-typedef struct sigcontext mcontext_t;
+} mcontext_t;
+typedef uint32_t kernel_sigset_t[4]; // MIPS kernel uses 128-bit signal
masks
typedef struct ucontext {
uint32_t uc_flags;
struct ucontext* uc_link;
stack_t uc_stack;
mcontext_t uc_mcontext;
- __sigset_t uc_sigmask;
+ kernel_sigset_t uc_sigmask;
} ucontext_t;
-#elif !defined(__GLIBC__) && defined(__i386__)
+#elif defined(__i386__)
// x86 version for Android.
-struct sigcontext {
+typedef struct {
uint32_t gregs[19];
void* fpregs;
uint32_t oldmask;
uint32_t cr2;
-};
+} mcontext_t;
-typedef uint32_t __sigset_t;
-typedef struct sigcontext mcontext_t;
+typedef uint32_t kernel_sigset_t[2]; // x86 kernel uses 64-bit signal
masks
typedef struct ucontext {
uint32_t uc_flags;
struct ucontext* uc_link;
stack_t uc_stack;
mcontext_t uc_mcontext;
- __sigset_t uc_sigmask;
+ kernel_sigset_t uc_sigmask;
} ucontext_t;
enum { REG_EBP = 6, REG_ESP = 7, REG_EIP = 14 };
#endif
+#endif // __ANDROID__ && !defined(__BIONIC_HAVE_UCONTEXT_T)
static int GetThreadID() {
- // Glibc doesn't provide a wrapper for gettid(2).
-#if defined(ANDROID)
- return syscall(__NR_gettid);
+#if defined(__ANDROID__)
+ // Android's C library provides gettid(2).
+ return gettid();
#else
+ // Glibc doesn't provide a wrapper for gettid(2).
return syscall(SYS_gettid);
#endif
}
@@ -1024,12 +1028,15 @@ static void ProfilerSignalHandler(int signal,
siginfo_t* info, void* context) {
sample->sp = reinterpret_cast<Address>(mcontext.gregs[REG_RSP]);
sample->fp = reinterpret_cast<Address>(mcontext.gregs[REG_RBP]);
#elif V8_HOST_ARCH_ARM
-// An undefined macro evaluates to 0, so this applies to Android's Bionic
also.
-#if (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
+#if defined(__GLIBC__) && \
+ (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
+ // Old GLibc ARM versions used a gregs[] array to access the register
+ // values from mcontext_t.
sample->pc = reinterpret_cast<Address>(mcontext.gregs[R15]);
sample->sp = reinterpret_cast<Address>(mcontext.gregs[R13]);
sample->fp = reinterpret_cast<Address>(mcontext.gregs[R11]);
#else
+ // Recent ARM GLibc and Android's Bionic use explicit named fields
instead.
sample->pc = reinterpret_cast<Address>(mcontext.arm_pc);
sample->sp = reinterpret_cast<Address>(mcontext.arm_sp);
sample->fp = reinterpret_cast<Address>(mcontext.arm_fp);
--
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