From 48b117618d239953acd5019294f6f0d1b41fa6a2 Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Thu, 19 Nov 2020 17:57:51 +0200
Subject: [PATCH] builtin: support -d no_backtrace, to ease compiling V code on
 older distros easier

---
 vlib/builtin/builtin_nix.c.v | 80 +++++++++++++++++++-----------------
 1 file changed, 42 insertions(+), 38 deletions(-)

diff --git a/vlib/builtin/builtin_nix.c.v b/vlib/builtin/builtin_nix.c.v
index 6648e3e3f6..9a75f4bf18 100644
--- a/vlib/builtin/builtin_nix.c.v
+++ b/vlib/builtin/builtin_nix.c.v
@@ -87,48 +87,52 @@ fn print_backtrace_skipping_top_frames_linux(skipframes int) bool {
 		C.tcc_backtrace("Backtrace")
 		return false
 	}
-	buffer := [100]byteptr{}
-	nr_ptrs := C.backtrace(voidptr(buffer), 100)
-	if nr_ptrs < 2 {
-		eprintln('C.backtrace returned less than 2 frames')
+	$if no_backtrace ? {
 		return false
-	}
-	nr_actual_frames := nr_ptrs - skipframes
-	mut sframes := []string{}
-	//////csymbols := backtrace_symbols(*voidptr(&buffer[skipframes]), nr_actual_frames)
-	csymbols := C.backtrace_symbols(voidptr(&buffer[skipframes]), nr_actual_frames)
-	for i in 0 .. nr_actual_frames {
-		sframes << unsafe {tos2( byteptr(csymbols[i]) )}
-	}
-	for sframe in sframes {
-		executable := sframe.all_before('(')
-		addr := sframe.all_after('[').all_before(']')
-		beforeaddr := sframe.all_before('[')
-		cmd := 'addr2line -e $executable $addr'
-		// taken from os, to avoid depending on the os module inside builtin.v
-		f := C.popen(charptr(cmd.str), 'r')
-		if isnil(f) {
-			eprintln(sframe)
-			continue
+	} $else {
+		buffer := [100]byteptr{}
+		nr_ptrs := C.backtrace(voidptr(buffer), 100)
+		if nr_ptrs < 2 {
+			eprintln('C.backtrace returned less than 2 frames')
+			return false
 		}
-		buf := [1000]byte{}
-		mut output := ''
-		for C.fgets(charptr(buf), 1000, f) != 0 {
-			output += tos(byteptr(buf), vstrlen(byteptr(buf)))
+		nr_actual_frames := nr_ptrs - skipframes
+		mut sframes := []string{}
+		//////csymbols := backtrace_symbols(*voidptr(&buffer[skipframes]), nr_actual_frames)
+		csymbols := C.backtrace_symbols(voidptr(&buffer[skipframes]), nr_actual_frames)
+		for i in 0 .. nr_actual_frames {
+			sframes << unsafe {tos2( byteptr(csymbols[i]) )}
 		}
-		output = output.trim_space() + ':'
-		if C.pclose(f) != 0 {
-			eprintln(sframe)
-			continue
+		for sframe in sframes {
+			executable := sframe.all_before('(')
+			addr := sframe.all_after('[').all_before(']')
+			beforeaddr := sframe.all_before('[')
+			cmd := 'addr2line -e $executable $addr'
+			// taken from os, to avoid depending on the os module inside builtin.v
+			f := C.popen(charptr(cmd.str), 'r')
+			if isnil(f) {
+				eprintln(sframe)
+				continue
+			}
+			buf := [1000]byte{}
+			mut output := ''
+			for C.fgets(charptr(buf), 1000, f) != 0 {
+				output += tos(byteptr(buf), vstrlen(byteptr(buf)))
+			}
+			output = output.trim_space() + ':'
+			if C.pclose(f) != 0 {
+				eprintln(sframe)
+				continue
+			}
+			if output in ['??:0:', '??:?:'] {
+				output = ''
+			}
+			// See http://wiki.dwarfstd.org/index.php?title=Path_Discriminators
+			// NB: it is shortened here to just d. , just so that it fits, and so
+			// that the common error file:lineno: line format is enforced.
+			output = output.replace(' (discriminator', ': (d.')
+			eprintln('${output:-46s} | ${addr:14s} | $beforeaddr')
 		}
-		if output in ['??:0:', '??:?:'] {
-			output = ''
-		}
-		// See http://wiki.dwarfstd.org/index.php?title=Path_Discriminators
-		// NB: it is shortened here to just d. , just so that it fits, and so
-		// that the common error file:lineno: line format is enforced.
-		output = output.replace(' (discriminator', ': (d.')
-		eprintln('${output:-46s} | ${addr:14s} | $beforeaddr')
 	}
 	return true
 }