From 37e37092ad3d25fec18920030a041226c5fe21a4 Mon Sep 17 00:00:00 2001
From: Petr Hosek <phosek@chromium.org>
Date: Fri, 19 Jan 2018 17:10:55 +0000
Subject: [PATCH] Fallback option for colorized output when terminfo isn't
 available

Try to detect the terminal color support by checking the value of the
TERM environment variable. This is not great, but it's better than
nothing when terminfo library isn't available, which may still be the
case on some Linux distributions.

Differential Revision: https://reviews.llvm.org/D42055

llvm-svn: 322962
---
 lib/Support/Unix/Process.inc | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/lib/Support/Unix/Process.inc b/lib/Support/Unix/Process.inc
index e43650d707e..7a4e3861400 100644
--- a/lib/Support/Unix/Process.inc
+++ b/lib/Support/Unix/Process.inc
@@ -369,6 +369,21 @@ static bool terminalHasColors(int fd) {
   // Return true if we found a color capabilities for the current terminal.
   if (HasColors)
     return true;
+#else
+  // When the terminfo database is not available, check if the current terminal
+  // is one of terminals that are known to support ANSI color escape codes.
+  if (const char *TermStr = std::getenv("TERM")) {
+    return StringSwitch<bool>(TermStr)
+      .Case("ansi", true)
+      .Case("cygwin", true)
+      .Case("linux", true)
+      .StartsWith("screen", true)
+      .StartsWith("xterm", true)
+      .StartsWith("vt100", true)
+      .StartsWith("rxvt", true)
+      .EndsWith("color", true)
+      .Default(false);
+  }
 #endif
 
   // Otherwise, be conservative.