From bf7402e8b0e74069f18310a26e7a3166fa90db96 Mon Sep 17 00:00:00 2001
From: Bartosz Taudul <bartosz.taudul@game-lion.com>
Date: Thu, 21 Jun 2018 17:07:21 +0200
Subject: [PATCH] Android callstack collection using _Unwind_Backtrace().

---
 client/TracyCallstack.cpp | 79 +++++++++++++++++++++++++++++++++++++++
 client/TracyCallstack.hpp | 38 +++++++++++++++++++
 2 files changed, 117 insertions(+)

diff --git a/client/TracyCallstack.cpp b/client/TracyCallstack.cpp
index e10d9762..5a8d433e 100644
--- a/client/TracyCallstack.cpp
+++ b/client/TracyCallstack.cpp
@@ -69,6 +69,85 @@ CallstackEntry DecodeCallstackPtr( uint64_t ptr )
     return ret;
 }
 
+#elif defined __ANDROID__
+
+CallstackEntry DecodeCallstackPtr( uint64_t ptr )
+{
+    CallstackEntry ret;
+    ret.line = 0;
+
+    char* demangled = nullptr;
+    const char* symname = nullptr;
+    const char* symloc = nullptr;
+    auto vptr = (void*)ptr;
+    char** sym = nullptr;
+    ptrdiff_t symoff = 0;
+
+    Dl_info dlinfo;
+    if( dladdr( vptr, &dlinfo ) )
+    {
+        symloc = dlinfo.dli_fname;
+        symname = dlinfo.dli_sname;
+        symoff = (char*)ptr - (char*)dlinfo.dli_saddr;
+
+        if( symname && symname[0] == '_' )
+        {
+            size_t len = 0;
+            int status;
+            demangled = abi::__cxa_demangle( symname, nullptr, &len, &status );
+            if( status == 0 )
+            {
+                symname = demangled;
+            }
+        }
+    }
+
+    if( !symname )
+    {
+        symname = "[unknown]";
+    }
+    if( !symloc )
+    {
+        symloc = "[unknown]";
+    }
+
+    if( symoff == 0 )
+    {
+        const auto namelen = strlen( symname );
+        auto name = (char*)tracy_malloc( namelen + 1 );
+        memcpy( name, symname, namelen );
+        name[namelen] = '\0';
+        ret.name = name;
+    }
+    else
+    {
+        char buf[32];
+        sprintf( buf, " + %td", symoff );
+        const auto offlen = strlen( buf );
+        const auto namelen = strlen( symname );
+        auto name = (char*)tracy_malloc( namelen + offlen + 1 );
+        memcpy( name, symname, namelen );
+        memcpy( name + namelen, buf, offlen );
+        name[namelen + offlen] = '\0';
+        ret.name = name;
+    }
+
+    char buf[32];
+    sprintf( buf, " [%p]", (void*)ptr );
+    const auto addrlen = strlen( buf );
+    const auto loclen = strlen( symloc );
+    auto loc = (char*)tracy_malloc( loclen + addrlen + 1 );
+    memcpy( loc, symloc, loclen );
+    memcpy( loc + loclen, buf, addrlen );
+    loc[loclen + addrlen] = '\0';
+    ret.file = loc;
+
+    if( sym ) free( sym );
+    if( demangled ) free( demangled );
+
+    return ret;
+}
+
 #elif defined _GNU_SOURCE
 
 CallstackEntry DecodeCallstackPtr( uint64_t ptr )
diff --git a/client/TracyCallstack.hpp b/client/TracyCallstack.hpp
index 90fc1104..5d2482df 100644
--- a/client/TracyCallstack.hpp
+++ b/client/TracyCallstack.hpp
@@ -10,6 +10,9 @@ extern "C" __declspec(dllimport) unsigned short __stdcall RtlCaptureStackBackTra
 extern "C" __declspec(dllimport) unsigned short __stdcall RtlCaptureStackBackTrace( unsigned long, unsigned long, void**, unsigned long* );
 #    endif
 #  endif
+#elif defined __ANDROID__
+#  define TRACY_HAS_CALLSTACK
+#  include <unwind.h>
 #elif defined _GNU_SOURCE
 #  define TRACY_HAS_CALLSTACK
 #  include <execinfo.h>
@@ -52,6 +55,41 @@ static tracy_force_inline void* Callstack( int depth )
     return trace;
 }
 
+#elif defined __ANDROID__
+
+static tracy_force_inline void InitCallstack() {}
+
+struct BacktraceState
+{
+    void** current;
+    void** end;
+};
+
+static _Unwind_Reason_Code tracy_unwind_callback( struct _Unwind_Context* ctx, void* arg )
+{
+    auto state = (BacktraceState*)arg;
+    uintptr_t pc = _Unwind_GetIP( ctx );
+    if( pc )
+    {
+        if( state->current == state->end ) return _URC_END_OF_STACK;
+        *state->current++ = (void*)pc;
+    }
+    return _URC_NO_REASON;
+}
+
+static tracy_force_inline void* Callstack( int depth )
+{
+    assert( depth >= 1 && depth < 63 );
+
+    auto trace = (uintptr_t*)tracy_malloc( ( 1 + depth ) * sizeof( uintptr_t ) );
+    BacktraceState state = { (void**)(trace+1), (void**)(trace+1+depth) };
+    _Unwind_Backtrace( tracy_unwind_callback, &state );
+
+    *trace = (uintptr_t*)state.current - trace + 1;
+
+    return trace;
+}
+
 #elif defined _GNU_SOURCE
 
 static tracy_force_inline void InitCallstack() {}