Strip the producers section in --strip

src/passes/Strip.cpp

@@ -15,10 +15,12 @@
  */
 
 //
-// Similar to strip-ing a native binary, this removes debug info
-// and related things like source map URLs, names section, etc.
+// Similar to strip-ing a native binary, this family of passes can
+// removes debug info and other things.
 //
 
+#include <functional>
+
 #include "wasm.h"
 #include "wasm-binary.h"
 #include "pass.h"
@@ -28,19 +30,20 @@ using namespace std;
 namespace wasm {
 
 struct Strip : public Pass {
+  // A function that returns true if the method should be removed.
+  typedef std::function<bool (UserSection&)> Decider;
+  Decider decider;
+
+  Strip(Decider decider) : decider(decider) {}
+
   void run(PassRunner* runner, Module* module) override {
     // Remove name and debug sections.
     auto& sections = module->userSections;
     sections.erase(
       std::remove_if(
         sections.begin(),
         sections.end(),
-        [&](const UserSection& curr) {
-          return curr.name == BinaryConsts::UserSections::Name ||
-                 curr.name == BinaryConsts::UserSections::SourceMapUrl ||
-                 curr.name.find(".debug") == 0 ||
-                 curr.name.find("reloc..debug") == 0;
-        }
+        decider
       ),
       sections.end()
     );
@@ -53,8 +56,19 @@ struct Strip : public Pass {
   }
 };
 
-Pass *createStripPass() {
-  return new Strip();
+Pass *createStripDebugPass() {
+  return new Strip([&](const UserSection& curr) {
+    return curr.name == BinaryConsts::UserSections::Name ||
+           curr.name == BinaryConsts::UserSections::SourceMapUrl ||
+           curr.name.find(".debug") == 0 ||
+           curr.name.find("reloc..debug") == 0;
+  });
+}
+
+Pass *createStripProducersPass() {
+  return new Strip([&](const UserSection& curr) {
+    return curr.name == BinaryConsts::UserSections::Producers;
+  });
 }
 
 } // namespace wasm

src/passes/pass.cpp

@@ -133,7 +133,9 @@ void PassRegistry::registerPasses() {
   registerPass("souperify-single-use", "emit Souper IR in text form (single-use nodes only)", createSouperifySingleUsePass);
   registerPass("spill-pointers", "spill pointers to the C stack (useful for Boehm-style GC)", createSpillPointersPass);
   registerPass("ssa", "ssa-ify variables so that they have a single assignment", createSSAifyPass);
-  registerPass("strip", "strip debug info (including the names section)", createStripPass);
+  registerPass("strip", "deprecated; same as strip-debug", createStripDebugPass);
+  registerPass("strip-debug", "strip debug info (including the names section)", createStripDebugPass);
+  registerPass("strip-producers", "strip the wasm producers section", createStripProducersPass);
   registerPass("trap-mode-clamp", "replace trapping operations with clamping semantics", createTrapModeClamp);
   registerPass("trap-mode-js", "replace trapping operations with js semantics", createTrapModeJS);
   registerPass("untee", "removes local.tees, replacing them with sets and gets", createUnteePass);

src/passes/passes.h

@@ -84,7 +84,8 @@ Pass* createSimplifyLocalsNoNestingPass();
 Pass* createSimplifyLocalsNoTeePass();
 Pass* createSimplifyLocalsNoStructurePass();
 Pass* createSimplifyLocalsNoTeeNoStructurePass();
-Pass* createStripPass();
+Pass* createStripDebugPass();
+Pass* createStripProducersPass();
 Pass* createSouperifyPass();
 Pass* createSouperifySingleUsePass();
 Pass* createSpillPointersPass();

src/wasm-binary.h

@@ -344,6 +344,7 @@ extern const char* Name;
 extern const char* SourceMapUrl;
 extern const char* Dylink;
 extern const char* Linking;
+extern const char* Producers;
 
 enum Subsection {
   NameFunction = 1,

src/wasm/wasm-binary.cpp

@@ -719,7 +719,7 @@ void WasmBinaryBuilder::readUserSection(size_t payloadLen) {
   } else {
     // an unfamiliar custom section
     if (sectionName.equals(BinaryConsts::UserSections::Linking)) {
-      std::cerr << "warning: linking section is present, which binaryen cannot handle yet - relocations will be invalidated!\n";
+      std::cerr << "warning: linking section is present, so this is not a standard wasm file - binaryen cannot handle this properly!\n";
     }
     wasm.userSections.resize(wasm.userSections.size() + 1);
     auto& section = wasm.userSections.back();

src/wasm/wasm.cpp

@@ -31,6 +31,7 @@ const char* Name = "name";
 const char* SourceMapUrl = "sourceMappingURL";
 const char* Dylink = "dylink";
 const char* Linking = "linking";
+const char* Producers = "producers";
 }
 }
 

test/metadatas.wasm.fromBinary

@@ -0,0 +1,10 @@
+(module
+ (type $0 (func))
+ (export "a" (func $0))
+ (func $0 (; 0 ;) (type $0)
+  (nop)
+ )
+ ;; custom section "emscripten_metadata", size 7
+ ;; custom section "producers", size 187
+)
+

test/passes/metrics_strip-debug_metrics.bin.txt

@@ -0,0 +1,17 @@
+total
+ [funcs]        : 1       
+ [total]        : 1       
+ nop            : 1       
+total
+ [funcs]        : 1       
+ [total]        : 1       
+ nop            : 1       
+(module
+ (type $0 (func))
+ (export "a" (func $0))
+ (func $0 (; 0 ;) (type $0)
+  (nop)
+ )
+ ;; custom section "emscripten_metadata", size 7
+ ;; custom section "producers", size 187
+)

test/passes/metrics_strip-producers_metrics.bin.txt

@@ -0,0 +1,16 @@
+total
+ [funcs]        : 1       
+ [total]        : 1       
+ nop            : 1       
+total
+ [funcs]        : 1       
+ [total]        : 1       
+ nop            : 1       
+(module
+ (type $0 (func))
+ (export "a" (func $0))
+ (func $0 (; 0 ;) (type $0)
+  (nop)
+ )
+ ;; custom section "emscripten_metadata", size 7
+)

test/passes/strip-producers.bin.txt

@@ -0,0 +1,22 @@
+(module
+ (type $0 (func (result i32)))
+ (import "env" "__linear_memory" (memory $0 0))
+ (import "env" "__indirect_function_table" (table $timport$1 0 funcref))
+ (func $0 (; 0 ;) (type $0) (result i32)
+  (local $0 i32)
+  (local.set $0
+   (i32.const 1)
+  )
+  (return
+   (local.get $0)
+  )
+ )
+ ;; custom section ".debug_str", size 246
+ ;; custom section ".debug_abbrev", size 52
+ ;; custom section ".debug_info", size 69
+ ;; custom section ".debug_macinfo", size 1
+ ;; custom section ".debug_line", size 56
+ ;; custom section "zinking", size 28
+ ;; custom section "reloc..debug_info", size 47
+ ;; custom section "reloc..debug_line", size 6
+)