From 043178bd25fdf32aaac53ee32ff8c90925621e1c Mon Sep 17 00:00:00 2001
From: Felix Brendel <felix@brendel.io>
Date: Sat, 15 May 2021 00:11:19 +0200
Subject: [PATCH] better stracktrace on linux (using gdb if wanted)

---
 macros.hpp     |  7 +++----
 stacktrace.hpp | 34 ++++++++++++++++++++++++++++++----
 2 files changed, 33 insertions(+), 8 deletions(-)

diff --git a/macros.hpp b/macros.hpp
index 692afea..21947f4 100644
--- a/macros.hpp
+++ b/macros.hpp
@@ -11,10 +11,9 @@
 #define proc auto
 #define concat(x, y) x ## y
 #define label(x, y) concat(x, y)
-#define line_label(x) label(x, __LINE__)
 
 #define MPI_LABEL(id1,id2)                                      \
-    concat(MPI_LABEL_ ## id1 ## _ ## id2 ## _, __LINE__)
+    label(MPI_LABEL_ ## id1 ## _ ## id2 ## _, __LINE__)
 
 #define MPP_DECLARE(labid, declaration)                 \
     if (0)                                              \
@@ -51,10 +50,10 @@
 
 
 // #ifndef min
-// #define min(a, b) ((a) < (b)) ? (a) : (b)
+#define min(a, b) ((a) < (b)) ? (a) : (b)
 // #endif
 // #ifndef max
-// #define max(a, b) ((a) > (b)) ? (a) : (b)
+#define max(a, b) ((a) > (b)) ? (a) : (b)
 // #endif
 
 /**
diff --git a/stacktrace.hpp b/stacktrace.hpp
index 81be6b4..838f79a 100644
--- a/stacktrace.hpp
+++ b/stacktrace.hpp
@@ -1,14 +1,23 @@
 #pragma once
 
 #include "platform.hpp"
+#include "allocation_stats.hpp"
 
 #if defined FTB_WINDOWS
 #  include <dbghelp.h>
 #else
-#  include <execinfo.h>
-#  include <unistd.h>
-#  include "stdio.h"
-#  include "stdlib.h"
+#  ifdef FTB_LINUX_STACK_TRACE_USE_GDB
+#    include <stdio.h>
+#    include <stdlib.h>
+#    include <sys/wait.h>
+#    include <unistd.h>
+#    include <sys/prctl.h>
+#  else
+#    include <execinfo.h>
+#    include <unistd.h>
+#    include "stdio.h"
+#    include "stdlib.h"
+#  endif
 #endif
 
 auto print_stacktrace() -> void {
@@ -33,6 +42,22 @@ auto print_stacktrace() -> void {
         printf( "  %3i: %s\n", frames - i - 1, symbol->Name);
     }
     fflush(stdout);
+#else
+#ifdef FTB_LINUX_STACK_TRACE_USE_GDB
+    printf("Stacktrace: \n");
+    char pid_buf[30];
+    sprintf(pid_buf, "%d", getpid());
+    char name_buf[512];
+    name_buf[readlink("/proc/self/exe", name_buf, 511)]=0;
+    prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY, 0, 0, 0);
+    int child_pid = fork();
+    if (!child_pid) {
+        dup2(2,1); // redirect output to stderr - edit: unnecessary?
+        execl("/usr/bin/gdb", "gdb", "--batch", "-n", "-ex", "thread", "-ex", "bt", name_buf, pid_buf, NULL);
+        abort(); /* If gdb failed to start */
+    } else {
+        waitpid(child_pid,NULL,0);
+   }
 #else
     // NOTE(Felix): Don't forget to compile with "-rdynamic"
     printf("Stacktrace (this is unmagled -- sorry): \n");
@@ -47,4 +72,5 @@ auto print_stacktrace() -> void {
     puts("");
     ftb_free(strings);
 #endif
+#endif
 }