Replace addr2line with libbacktrace to get improved stack traces

1 files changed, 126 insertions, 0 deletions

diff --git a/src/stdlib/stacktrace.c b/src/stdlib/stacktrace.c
new file mode 100644
index 00000000..bd867c7b
--- /dev/null
+++ b/src/stdlib/stacktrace.c
@@ -0,0 +1,126 @@
+#include <backtrace.h>
+#include <err.h>
+#include <gc.h>
+#include <signal.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "util.h"
+
+extern bool USE_COLOR;
+
+static struct backtrace_state *bt_state = NULL;
+
+static void fprint_context(FILE *out, const char *filename, int lineno, int context_before, int context_after)
+{
+    FILE *f = fopen(filename, "r");
+    if (!f) return;
+    char *line = NULL;
+    size_t size = 0;
+    ssize_t nread;
+    int64_t cur_line = 1;
+
+    int num_width = 1;
+    for (int n = lineno + context_after; n >= 10; n /= 10)
+        num_width += 1;
+
+    while ((nread = getline(&line, &size, f)) != -1) {
+        if (line[strlen(line)-1] == '\n')
+            line[strlen(line)-1] = '\0';
+
+        if (cur_line >= lineno - context_before)
+            fprintf(out, USE_COLOR ? "%s\033[2m%*d\033(0\x78\x1b(B%s%s\033[m\n" : "%s%*d| %s%s\n",
+                    cur_line == lineno ? (USE_COLOR ? "\033[31;1m>\033[m " : "> ") : "  ",
+                    num_width, cur_line, USE_COLOR ? (cur_line == lineno ? "\033[0;31;1m" : "\033[0m") : "", line);
+
+        cur_line += 1;
+        if (cur_line > lineno + context_after)
+            break;
+    }
+    if (line) free(line);
+    fclose(f);
+}
+
+typedef struct stack_info_s {
+    const char *function, *filename;
+    int lineno;
+    struct stack_info_s *next;
+} stack_info_t;
+
+// Simple callback to print each frame
+static int print_callback(void *data, uintptr_t pc, const char *filename, int lineno, const char *function)
+{
+    (void)pc;
+    stack_info_t *info = GC_MALLOC(sizeof(stack_info_t));
+    info->next = *(stack_info_t**)data;
+    info->function = function;
+    info->filename = filename;
+    info->lineno = lineno;
+    *(stack_info_t**)data = info;
+    return 0;
+}
+
+public void print_stacktrace(FILE *out, int offset)
+{
+    stack_info_t *backwards = NULL;
+
+    backtrace_full(bt_state, offset, print_callback, NULL, &backwards);
+
+    char cwd[PATH_MAX];
+    if (getcwd(cwd, sizeof(cwd)) == NULL)
+        errx(1, "Path too large!");
+    size_t cwd_len = strlen(cwd);
+    if (cwd_len + 2 > sizeof(cwd))
+        errx(1, "Path too large!");
+    cwd[cwd_len++] = '/';
+    cwd[cwd_len] = '\0';
+
+    // Skip C entrypoint stuff:
+    while (backwards && backwards->function == NULL)
+        backwards = backwards->next;
+
+    if (backwards && strstr(backwards->function, "$parse_and_run"))
+        backwards = backwards->next;
+
+    for (stack_info_t *frame = backwards; frame; frame = frame->next) {
+        while (frame && frame->function == NULL) {
+            fprintf(out, USE_COLOR ? "\033[2m... unknown function ...\033[m\n" : "... unknown function ...\n");
+            if (frame->next)
+                fprintf(out, "\n");
+            frame = frame->next;
+        }
+        if (frame == NULL) break;
+
+        char *function_display = GC_MALLOC_ATOMIC(strlen(frame->function));
+        memcpy(function_display, frame->function, strlen(frame->function)+1);
+        function_display += strcspn(function_display, "$");
+        function_display += strspn(function_display, "$");
+        function_display += strcspn(function_display, "$");
+        function_display += strspn(function_display, "$");
+        for (char *p = function_display; *p; p++) {
+            if (*p == '$') *p = '.';
+        }
+
+        if (strncmp(frame->filename, cwd, cwd_len) == 0)
+            frame->filename += cwd_len;
+
+        fprintf(out, USE_COLOR ? "\033[1mIn \033[33m%s()\033[37m" : "In %s()", function_display);
+        if (frame->filename)
+            fprintf(out, USE_COLOR ? " in \033[35m%s:%d" : " in %s:%d", frame->filename, frame->lineno);
+        fprintf(out, USE_COLOR ? "\033[m\n" : "\n");
+        if (frame->filename)
+            fprint_context(out, frame->filename, frame->lineno, 3, 1);
+        if (frame->next)
+            fprintf(out, "\n");
+    }
+}
+
+public void initialize_stacktrace(const char *program)
+{
+    bt_state = backtrace_create_state(program, 1, NULL, NULL);
+    if (!bt_state)
+        errx(1, "Failed to create stacktrace state");
+}