[gn build] Slighly nicer `gn args --list` output for is_debug and symbol_level

diff --git a/llvm/utils/gn/build/buildflags.gni b/llvm/utils/gn/build/buildflags.gni
index e6d7ca1806a9fbb974a9a707c940bfe8051bea2a..ca43a2499edcb217da53823acc3e05ca2df50945 100644 (file)
--- a/llvm/utils/gn/build/buildflags.gni
+++ b/llvm/utils/gn/build/buildflags.gni
@@ -1,5 +1,5 @@
 declare_args() {
-  # Whether to build with debug information.
+  # Build for debugging. Equivalent to is_optimized=false symbol_level=2.
   is_debug = false
 
   # Whether to build with tsan.
@@ -29,10 +29,11 @@ declare_args() {
   # Whether to build with optimizations.
   is_optimized = !is_debug
 
-  # Debug info symbol level.
   if (is_debug) {
+    # Debug info symbol level. 0: No symbols; 1: Line numbers; 2: Full symbols.
     symbol_level = 2
   } else {
+    # Debug info symbol level. 0: No symbols; 1: Line numbers; 2: Full symbols.
     symbol_level = 0
   }
 }