When running wasm-opt, ignore any failure because it will fail for unknown flags and the set of legal flags will change from version to version. Document the size-reduction effect (or non-effect) of a dozen-odd wasm-opt flags and retain those which demonstrate a wasm file size reduction in -Oz builds (our production build mode). Total size savings: roughly 13kb.

FossilOrigin-Name: c9dc581e0287e3462ac55f80ca76e7e98d31157022052c892517363c45287a7b

ext/wasm/mkwasmbuilds.c

@@ -65,23 +65,74 @@ static void mk_prologue(void){
   ps("# --[extern-][pre/post]-js files.");
   ps("pre-post-jses.deps.common := $(extern-pre-js.js) $(sqlite3-license-version.js)");
 
-  /* SQLITE.CALL.WASM-OPT = shell code to run $(1) (source wasm file
-  ** name) through $(bin.wasm-opt) */
-  ps("ifeq (,$(bin.wasm-opt))");
-  ps("define SQLITE.CALL.WASM-OPT");
-  ps("echo 'wasm-opt not available for $(1)'");
-  ps("endef");
-  ps("else");
-  ps("define SQLITE.CALL.WASM-OPT");
-  ps("echo -n 'Before wasm-opt:'; ls -l $(1);\\\n"
-     "\trm -f wasm-opt-tmp.wasm;\\\n"
-     "\t$(bin.wasm-opt) --enable-bulk-memory-opt --all-features --post-emscripten\\\n"
-     "\t$(1) -o wasm-opt-tmp.wasm || exit;\\\n"
-     "\tmv wasm-opt-tmp.wasm $(1); "
-     "echo -n 'After wasm-opt: '; ls -l $(1)"
-  );
-  ps("endef");
-  ps("endif");
+  {
+    /* SQLITE.CALL.WASM-OPT = shell code to run $(1) (source wasm file
+    ** name) through $(bin.wasm-opt) */
+    const char * zOptFlags =
+      /*
+      ** Flags for wasm-opt. It has many, many, MANY "passes" options
+      ** and the ones which appear here were selected solely on the
+      ** basis of trial and error.
+      **
+      ** All wasm file size savings/costs mentioned below are based on
+      ** the vanilla build of sqlite3.wasm with -Oz (our shipping
+      ** configuration). Comments like "saves nothing" may not be
+      ** technically correct: "nothing" means "some neglible amount."
+      **
+      ** Note that performance gains/losses are _not_ taken into
+      ** account here: only wasm file size.
+      */
+      "--enable-bulk-memory-opt " /* required */
+      "--all-features "           /* required */
+      "--post-emscripten "        /* Saves roughly 12kb */
+      "--strip-debug "            /* We already wasm-strip, but in
+                                  ** case this environment has no
+                                  ** wasm-strip... */
+      /*
+      ** The rest are trial-and-error. See wasm-opt --help and search
+      ** for "Optimization passes" to find the full list.
+      **
+      ** With many flags this gets unusuably slow.
+      */
+      /*"--converge " saves nothing for the options we're using */
+      /*"--dce " saves nothing */
+      /*"--directize " saves nothing */
+      /*"--gsi " no: requires --closed-world flag, which does not
+      ** sound like something we want. */
+      /*"--gufa --gufa-cast-all --gufa-optimizing " costs roughly 2kb */
+      /*"--heap-store-optimization " saves nothing */
+      /*"--heap2local " saves nothing */
+      //"--inlining --inlining-optimizing " costs roughly 3kb */
+      "--local-cse " /* saves roughly 1kb */
+      /*"--once-reduction " saves nothing */
+      /*"--remove-memory-init " presumably a performance tweak */
+      /*"--remove-unused-names " saves nothing */
+      /*"--safe-heap "*/
+      /*"--vacuum " saves nothing */
+      ;
+    ps("ifeq (,$(bin.wasm-opt))");
+    ps("define SQLITE.CALL.WASM-OPT");
+    ps("echo 'wasm-opt not available for $(1)'");
+    ps("endef");
+    ps("else");
+    ps("define SQLITE.CALL.WASM-OPT");
+    pf("echo -n 'Before wasm-opt:'; ls -l $(1);\\\n"
+       "\trm -f wasm-opt-tmp.wasm;\\\n"
+       /* It's very likely that the set of wasm-opt flags varies from
+       ** version to version, so we'll ignore any errors here. */
+       "\tif $(bin.wasm-opt) $(1) -o wasm-opt-tmp.wasm \\\n"
+       "\t\t%s; then \\\n"
+       "\t\tmv wasm-opt-tmp.wasm $(1); \\\n"
+       "\t\techo -n 'After wasm-opt: '; \\\n"
+       "\t\tls -l $(1); \\\n"
+       "\telse \\\n"
+       "\t\techo 'WARNING: ignoring wasm-opt failure'; \\\n"
+       "\tfi\n",
+       zOptFlags
+    );
+    ps("endef");
+    ps("endif");
+  }
 }
 
 /*

manifest

@@ -1,5 +1,5 @@
-C Remove\ssome\snow-dead\smakefile\scode,\srename\sa\svar\sfor\sconsistency,\sand\sfix\sa\srecipe\sbug\sintroduced\sin\sthe\sprevious\scheckin\sin\sthe\sbundler-friendly\sbuild.
-D 2025-01-23T16:11:24.436
+C When\srunning\swasm-opt,\signore\sany\sfailure\sbecause\sit\swill\sfail\sfor\sunknown\sflags\sand\sthe\sset\sof\slegal\sflags\swill\schange\sfrom\sversion\sto\sversion.\s\sDocument\sthe\ssize-reduction\seffect\s(or\snon-effect)\sof\sa\sdozen-odd\swasm-opt\sflags\sand\sretain\sthose\swhich\sdemonstrate\sa\swasm\sfile\ssize\sreduction\sin\s-Oz\sbuilds\s(our\sproduction\sbuild\smode).\sTotal\ssize\ssavings:\sroughly\s13kb.
+D 2025-01-23T19:44:09.613
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md e108e1e69ae8e8a59e93c455654b8ac9356a11720d3345df2a4743e9590fb20d
@@ -679,7 +679,7 @@ F ext/wasm/index-dist.html 564b5ec5669676482c5a25dea9e721d8eafed426ecb155f93d29a
 F ext/wasm/index.html e4bbffdb3d40eff12b3f9c7abedef91787e2935620b7f8d40f2c774b80ad8fa9
 F ext/wasm/jaccwabyt/jaccwabyt.js 1264710db3cfbcb6887d95665b7aeba60c1126eaef789ca4cf1a4a17d5bc7f54
 F ext/wasm/jaccwabyt/jaccwabyt.md 59a20df389abcc3606eb4eaea7fb7ba14504beb3e345dbea9b99a0618ba3bec8
-F ext/wasm/mkwasmbuilds.c 0c85aef64ac94f903964c046e7d5a291a95afbbc881d2a96b7871e825e1d175c
+F ext/wasm/mkwasmbuilds.c 1d5ba1e274d0331b2c8549b288ed108f6764674deb3fa7105b0bb0cea6f68cd5
 F ext/wasm/module-symbols.html dc476b403369b26a1a23773e13b80f41b9a49f0825e81435fe3600a7cfbbe337
 F ext/wasm/scratchpad-wasmfs.html a3d7388f3c4b263676b58b526846e9d02dfcb4014ff29d3a5040935286af5b96
 F ext/wasm/scratchpad-wasmfs.mjs 66034b9256b218de59248aad796760a1584c1dd842231505895eff00dbd57c63
@@ -2208,8 +2208,8 @@ F tool/version-info.c 3b36468a90faf1bbd59c65fd0eb66522d9f941eedd364fabccd7227350
 F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee87c1b31a7
 F tool/warnings.sh 49a486c5069de041aedcbde4de178293e0463ae9918ecad7539eedf0ec77a139
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 5d16e3f28364de2d6b6456a6fc56bf604b9106c3ae15719f2862192ae3020cc1
-R f70ac1b6c598112d9638929ed475c3d8
+P 0acd4ef3addb311476f4a670be0c4c4a0f3f88b0420886d4c1c3c3027dd51d73
+R 1bff543c29d839d27b34bab0c548a658
 U stephan
-Z e841368168cc448b3b9bb4f562d2f5fb
+Z 154b3ea92135b6fb56c35822cc74d582
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-0acd4ef3addb311476f4a670be0c4c4a0f3f88b0420886d4c1c3c3027dd51d73
+c9dc581e0287e3462ac55f80ca76e7e98d31157022052c892517363c45287a7b