Add --compress-sysimage flag; use zstd-15 when enabled

Author: xal-0

base/options.jl

@@ -67,6 +67,7 @@ struct JLOptions
     task_metrics::Int8
     timeout_for_safepoint_straggler_s::Int16
     gc_sweep_always_full::Int8
+    compress_sysimage::Int8
 end
 
 # This runs early in the sysimage != is not defined yet

base/util.jl

@@ -245,6 +245,9 @@ function julia_cmd(julia=joinpath(Sys.BINDIR, julia_exename()); cpu_target::Unio
     if opts.use_sysimage_native_code == 0
         push!(addflags, "--sysimage-native-code=no")
     end
+    if opts.compress_sysimage == 1
+        push!(addflags, "--compress-sysimage=yes")
+    end
     return `$julia -C $cpu_target -J$image_file $addflags`
 end
 

src/aotcompile.cpp

@@ -2149,8 +2149,7 @@ void jl_dump_native_impl(void *native_code,
         sysimgM.setStackProtectorGuard(StackProtectorGuard);
         sysimgM.setOverrideStackAlignment(OverrideStackAlignment);
 
-        char *compression_str = getenv("JULIA_IMAGE_COMPRESSION");
-        unsigned long compression = compression_str ? strtoul(compression_str, nullptr, 10) : 0;
+        int compression = jl_options.compress_sysimage ? 15 : 0;
         ArrayRef<char> sysimg_data{z->buf, (size_t)z->size};
         SmallVector<char, 0> compressed_data;
         if (compression) {

src/jloptions.c

@@ -160,6 +160,7 @@ JL_DLLEXPORT void jl_init_options(void)
                         0, // task_metrics
                         -1, // timeout_for_safepoint_straggler_s
                         0, // gc_sweep_always_full
+                        0, // compress_sysimage
     };
     jl_options_initialized = 1;
 }
@@ -311,7 +312,10 @@ static const char opts_hidden[]  =
     " --strip-metadata                              Remove docstrings and source location info from\n"
     "                                               system image\n"
     " --strip-ir                                    Remove IR (intermediate representation) of compiled\n"
-    "                                               functions\n\n"
+    "                                               functions\n"
+    " --compress-sysimage={yes|no*}                 Compress the sys/pkgimage heap at the expense of\n"
+    "                                               slightly increased load time.\n"
+    "\n"
 
     // compiler debugging and experimental (see the devdocs for tips on using these options)
     " --experimental                                Enable the use of experimental (alpha) features\n"
@@ -407,6 +411,7 @@ JL_DLLEXPORT void jl_parse_opts(int *argcp, char ***argvp)
            opt_permalloc_pkgimg,
            opt_trim,
            opt_experimental_features,
+           opt_compress_sysimage,
     };
     static const char* const shortopts = "+vhqH:e:E:L:J:C:it:p:O:g:m:";
     static const struct option longopts[] = {
@@ -478,6 +483,7 @@ JL_DLLEXPORT void jl_parse_opts(int *argcp, char ***argvp)
         { "heap-target-increment", required_argument, 0, opt_heap_target_increment },
         { "gc-sweep-always-full", no_argument, 0, opt_gc_sweep_always_full },
         { "trim",  optional_argument, 0, opt_trim },
+        { "compress-sysimage", required_argument, 0, opt_compress_sysimage },
         { 0, 0, 0, 0 }
     };
 
@@ -1060,6 +1066,12 @@ JL_DLLEXPORT void jl_parse_opts(int *argcp, char ***argvp)
             else
                 jl_errorf("julia: invalid argument to --task-metrics={yes|no} (%s)", optarg);
             break;
+        case opt_compress_sysimage:
+            if (!strcmp(optarg,"yes"))
+                jl_options.compress_sysimage = 1;
+            else if (!strcmp(optarg,"no"))
+                jl_options.compress_sysimage = 0;
+            break;
         default:
             jl_errorf("julia: unhandled option -- %c\n"
                       "This is a bug, please report it.", c);

src/jloptions.h

@@ -71,6 +71,7 @@ typedef struct {
     int8_t task_metrics;
     int16_t timeout_for_safepoint_straggler_s;
     int8_t gc_sweep_always_full;
+    int8_t compress_sysimage;
 } jl_options_t;
 
 #endif