打印Android HAL層堆棧

 

1.頭文件
./system/core/include/utils/CallStack.h

依賴庫：

Android O及更低版本：

android P以上版本：libutilscallstack

2.使用

#include <utils/CallStack.h>

android::CallStack stack;
stack.update(1);
stack.log("xxx");

3.Callstack類及其成員

// Collect/print the call stack (function, file, line) traces for a single thread.
class CallStack {
public:
    enum {
        // Prune the lowest-most stack frames until we have at most MAX_DEPTH.

 

 

        MAX_DEPTH = 31,

 

 

        // Placeholder for specifying the current thread when updating the stack.
        CURRENT_THREAD = -1,
    };

    // Create an empty call stack. No-op.
    CallStack();

    // Create a callstack with the current thread's stack trace.
    // Immediately dump it to logcat using the given logtag.
    CallStack(const char* logtag, int32_t ignoreDepth=1,

            int32_t maxDepth=MAX_DEPTH);

    // Copy the existing callstack (no other side effects).
    CallStack(const CallStack& rhs);

    ~CallStack();

    // Copy the existing callstack (no other side effects).
    CallStack& operator = (const CallStack& rhs);

    // Compare call stacks by their backtrace frame memory.
    bool operator == (const CallStack& rhs) const;

    bool operator != (const CallStack& rhs) const;

    bool operator < (const CallStack& rhs) const;

    bool operator >= (const CallStack& rhs) const;

    bool operator > (const CallStack& rhs) const;

    bool operator <= (const CallStack& rhs) const;

    // Get the PC address for the stack frame specified by index.
    const void* operator [] (int index) const;

    // Reset the stack frames (same as creating an empty call stack).
    void clear();

    // Immediately collect the stack traces for the specified thread.
    void update(int32_t ignoreDepth=1, int32_t maxDepth=MAX_DEPTH, pid_t tid=CURRENT_THREAD);

打印log函數

    // Dump a stack trace to the log using the supplied logtag.

    void log(const char* logtag,

             android_LogPriority priority = ANDROID_LOG_DEBUG,

             const char* prefix = 0) const;

 

    // Dump a stack trace to the specified file descriptor.
    void dump(int fd, int indent = 0, const char* prefix = 0) const;

    // Return a string (possibly very long) containing the complete stack trace.
    String8 toString(const char* prefix = 0) const;

    // Dump a serialized representation of the stack trace to the specified printer.
    void print(Printer& printer) const;

    // Get the count of stack frames that are in this call stack.
    size_t size() const { return mCount; }

private:
    size_t mCount;
    backtrace_frame_t mStack[MAX_DEPTH];
};