diff --git a/make/autoconf/flags-cflags.m4 b/make/autoconf/flags-cflags.m4
index 6298bcae416..1a6a040965b 100644
--- a/make/autoconf/flags-cflags.m4
+++ b/make/autoconf/flags-cflags.m4
@@ -93,8 +93,25 @@ AC_DEFUN([FLAGS_SETUP_DEBUG_SYMBOLS],
       )
     fi
 
-    CFLAGS_DEBUG_SYMBOLS="-g -gdwarf-4"
-    ASFLAGS_DEBUG_SYMBOLS="-g"
+    # Enough to produce viable backtrace without blowing up debug info size.
+    GCC_DEBUG_LEVEL=1
+
+    case $DEBUG_LEVEL in
+      slowdebug )
+        # Default to produce debuggable binaries
+        GCC_DEBUG_LEVEL=2
+        ;;
+    esac
+
+    UTIL_ARG_WITH(NAME: gcc-debug-level, TYPE: string,
+      DEFAULT: ${GCC_DEBUG_LEVEL},
+      RESULT: GCC_DEBUG_LEVEL,
+      DESC: [Sets the GCC debug level, when debug info generation is enabled],
+      DEFAULT_DESC: [from build debug level])
+    AC_SUBST(GCC_DEBUG_LEVEL)
+
+    CFLAGS_DEBUG_SYMBOLS="-gdwarf-4 -g${GCC_DEBUG_LEVEL}"
+    ASFLAGS_DEBUG_SYMBOLS="-g${GCC_DEBUG_LEVEL}"
   elif test "x$TOOLCHAIN_TYPE" = xclang; then
     if test "x$ALLOW_ABSOLUTE_PATHS_IN_OUTPUT" = "xfalse"; then
       # Check if compiler supports -fdebug-prefix-map. If so, use that to make
diff --git a/make/langtools/src/classes/build/tools/symbolgenerator/CreateSymbols.java b/make/langtools/src/classes/build/tools/symbolgenerator/CreateSymbols.java
index fe5938ce0e3..220face0868 100644
--- a/make/langtools/src/classes/build/tools/symbolgenerator/CreateSymbols.java
+++ b/make/langtools/src/classes/build/tools/symbolgenerator/CreateSymbols.java
@@ -282,6 +282,8 @@ public void createSymbols(String ctDescriptionFileExtra, String ctDescriptionFil
         try (OutputStream fos = new FileOutputStream(ctSymLocation);
              OutputStream bos = new BufferedOutputStream(fos);
              ZipOutputStream jos = new ZipOutputStream(bos)) {
+            // Do not compress ct.sym, allow external compressor to work on it.
+            jos.setLevel(0);
             for (Entry<String, Set<FileData>> e : directory2FileData.entrySet()) {
                 jos.putNextEntry(createZipEntry(e.getKey(), timestamp));
                 for (FileData fd : e.getValue()) {