[wasm-split] Minimize names of newly created exports (#3905)

wasm-split would previously use internal function names to create the external
names of the functions that are newly exported from the primary module to be
imported into the secondary module. When the input module contains full function
names (as is commonly the case when emitting symbol maps), this caused the
function names to be preserved as the export names, even when names are
otherwise being stripped. To save on code size and properly anonymize functions,
generate minimal export names when debuginfo is disabled instead.

4 files changed, 198 insertions, 44 deletions

diff --git a/test/example/module-splitting.cpp b/test/example/module-splitting.cpp
index 5391fe584..2aa67d6d5 100644
--- a/test/example/module-splitting.cpp
+++ b/test/example/module-splitting.cpp
@@ -64,6 +64,8 @@ void do_test(const std::set<Name>& keptFuncs, std::string&& module) {
   assert(valid && "secondary invalid!");
 }
 
+void test_minimized_exports();
+
 int main() {
   // Trivial module
   do_test({}, "(module)");
@@ -437,4 +439,46 @@ int main() {
      (export "foo2" (func $foo))
      (func $foo)
     ))");
+
+  test_minimized_exports();
+}
+
+void test_minimized_exports() {
+  Module primary;
+  primary.features = FeatureSet::All;
+
+  std::set<Name> keep;
+  Expression* callBody = nullptr;
+
+  Builder builder(primary);
+
+  for (size_t i = 0; i < 10; ++i) {
+    Name name = std::to_string(i);
+    primary.addFunction(Builder::makeFunction(name, {}, {}, builder.makeNop()));
+    keep.insert(name);
+    callBody =
+      builder.blockify(callBody, builder.makeCall(name, {}, Type::none));
+
+    if (i == 3) {
+      primary.addExport(
+        Builder::makeExport("already_exported", name, ExternalKind::Function));
+    }
+    if (i == 7) {
+      primary.addExport(
+        Builder::makeExport("%b", name, ExternalKind::Function));
+    }
+  }
+
+  primary.addFunction(Builder::makeFunction("call", {}, {}, callBody));
+
+  ModuleSplitting::Config config;
+  config.primaryFuncs = std::move(keep);
+  config.newExportPrefix = "%";
+  config.minimizeNewExportNames = true;
+
+  auto secondary = splitFunctions(primary, config);
+  std::cout << "Minimized names primary:\n";
+  std::cout << primary << "\n";
+  std::cout << "Minimized names secondary:\n";
+  std::cout << *secondary << "\n";
 }
diff --git a/test/example/module-splitting.txt b/test/example/module-splitting.txt
index 5c3728cde..2b92e9dd6 100644
--- a/test/example/module-splitting.txt
+++ b/test/example/module-splitting.txt
@@ -1107,3 +1107,75 @@ Secondary:
 )
 
 
+Minimized names primary:
+(module
+ (type $none_=>_none (func))
+ (export "already_exported" (func $3))
+ (export "%b" (func $7))
+ (export "%a" (func $0))
+ (export "%c" (func $1))
+ (export "%d" (func $2))
+ (export "%e" (func $4))
+ (export "%f" (func $5))
+ (export "%g" (func $6))
+ (export "%h" (func $8))
+ (export "%i" (func $9))
+ (func $0
+  (nop)
+ )
+ (func $1
+  (nop)
+ )
+ (func $2
+  (nop)
+ )
+ (func $3
+  (nop)
+ )
+ (func $4
+  (nop)
+ )
+ (func $5
+  (nop)
+ )
+ (func $6
+  (nop)
+ )
+ (func $7
+  (nop)
+ )
+ (func $8
+  (nop)
+ )
+ (func $9
+  (nop)
+ )
+)
+
+Minimized names secondary:
+(module
+ (type $none_=>_none (func))
+ (import "primary" "%a" (func $0))
+ (import "primary" "%c" (func $1))
+ (import "primary" "%d" (func $2))
+ (import "primary" "already_exported" (func $3))
+ (import "primary" "%e" (func $4))
+ (import "primary" "%f" (func $5))
+ (import "primary" "%g" (func $6))
+ (import "primary" "%b" (func $7))
+ (import "primary" "%h" (func $8))
+ (import "primary" "%i" (func $9))
+ (func $call
+  (call $0)
+  (call $1)
+  (call $2)
+  (call $3)
+  (call $4)
+  (call $5)
+  (call $6)
+  (call $7)
+  (call $8)
+  (call $9)
+ )
+)
+
diff --git a/test/lit/wasm-split/basic.wast b/test/lit/wasm-split/basic.wast
index 98fe433f3..7bbc14b49 100644
--- a/test/lit/wasm-split/basic.wast
+++ b/test/lit/wasm-split/basic.wast
@@ -1,19 +1,19 @@
-;; RUN: wasm-split %s --export-prefix='%' -o1 %t.none.1.wasm -o2 %t.none.2.wasm -v 2>&1 \
+;; RUN: wasm-split %s --export-prefix='%' -g -o1 %t.none.1.wasm -o2 %t.none.2.wasm -v 2>&1 \
 ;; RUN:     | filecheck %s --check-prefix KEEP-NONE
 ;; RUN: wasm-dis %t.none.1.wasm | filecheck %s --check-prefix KEEP-NONE-PRIMARY
 ;; RUN: wasm-dis %t.none.2.wasm | filecheck %s --check-prefix KEEP-NONE-SECONDARY
 
-;; RUN: wasm-split %s --export-prefix='%' -o1 %t.foo.1.wasm -o2 %t.foo.2.wasm --keep-funcs=foo -v 2>&1 \
+;; RUN: wasm-split %s --export-prefix='%' -g -o1 %t.foo.1.wasm -o2 %t.foo.2.wasm --keep-funcs=foo -v 2>&1 \
 ;; RUN:     | filecheck %s --check-prefix KEEP-FOO
 ;; RUN: wasm-dis %t.foo.1.wasm | filecheck %s --check-prefix KEEP-FOO-PRIMARY
 ;; RUN: wasm-dis %t.foo.2.wasm | filecheck %s --check-prefix KEEP-FOO-SECONDARY
 
-;; RUN: wasm-split %s --export-prefix='%' -o1 %t.bar.1.wasm -o2 %t.bar.2.wasm --keep-funcs=bar -v 2>&1 \
+;; RUN: wasm-split %s --export-prefix='%' -g -o1 %t.bar.1.wasm -o2 %t.bar.2.wasm --keep-funcs=bar -v 2>&1 \
 ;; RUN:     | filecheck %s --check-prefix KEEP-BAR
 ;; RUN: wasm-dis %t.bar.1.wasm | filecheck %s --check-prefix KEEP-BAR-PRIMARY
 ;; RUN: wasm-dis %t.bar.2.wasm | filecheck %s --check-prefix KEEP-BAR-SECONDARY
 
-;; RUN: wasm-split %s --export-prefix='%' -o1 %t.both.1.wasm -o2 %t.both.2.wasm --keep-funcs=foo,bar -v 2>&1 \
+;; RUN: wasm-split %s --export-prefix='%' -g -o1 %t.both.1.wasm -o2 %t.both.2.wasm --keep-funcs=foo,bar -v 2>&1 \
 ;; RUN:     | filecheck %s --check-prefix KEEP-BOTH
 ;; RUN: wasm-dis %t.both.1.wasm | filecheck %s --check-prefix KEEP-BOTH-PRIMARY
 ;; RUN: wasm-dis %t.both.2.wasm | filecheck %s --check-prefix KEEP-BOTH-SECONDARY
@@ -33,23 +33,23 @@
 
 ;; KEEP-NONE-PRIMARY:      (module
 ;; KEEP-NONE-PRIMARY-NEXT:  (type $i32_=>_i32 (func (param i32) (result i32)))
-;; KEEP-NONE-PRIMARY-NEXT:  (import "placeholder" "0" (func $fimport$0 (param i32) (result i32)))
-;; KEEP-NONE-PRIMARY-NEXT:  (table $0 1 1 funcref)
-;; KEEP-NONE-PRIMARY-NEXT:  (elem (i32.const 0) $fimport$0)
-;; KEEP-NONE-PRIMARY-NEXT:  (export "%table" (table $0))
+;; KEEP-NONE-PRIMARY-NEXT:  (import "placeholder" "0" (func $placeholder_0 (param i32) (result i32)))
+;; KEEP-NONE-PRIMARY-NEXT:  (table $table 1 1 funcref)
+;; KEEP-NONE-PRIMARY-NEXT:  (elem (i32.const 0) $placeholder_0)
+;; KEEP-NONE-PRIMARY-NEXT:  (export "%table" (table $table))
 ;; KEEP-NONE-PRIMARY-NEXT: )
 
 ;; KEEP-NONE-SECONDARY:      (module
 ;; KEEP-NONE-SECONDARY-NEXT:  (type $i32_=>_i32 (func (param i32) (result i32)))
-;; KEEP-NONE-SECONDARY-NEXT:  (import "primary" "%table" (table $timport$0 1 1 funcref))
-;; KEEP-NONE-SECONDARY-NEXT:  (elem (i32.const 0) $1)
-;; KEEP-NONE-SECONDARY-NEXT:  (func $0 (param $0 i32) (result i32)
-;; KEEP-NONE-SECONDARY-NEXT:   (call $1
+;; KEEP-NONE-SECONDARY-NEXT:  (import "primary" "%table" (table $table 1 1 funcref))
+;; KEEP-NONE-SECONDARY-NEXT:  (elem (i32.const 0) $foo)
+;; KEEP-NONE-SECONDARY-NEXT:  (func $bar (param $0 i32) (result i32)
+;; KEEP-NONE-SECONDARY-NEXT:   (call $foo
 ;; KEEP-NONE-SECONDARY-NEXT:    (i32.const 1)
 ;; KEEP-NONE-SECONDARY-NEXT:   )
 ;; KEEP-NONE-SECONDARY-NEXT:  )
-;; KEEP-NONE-SECONDARY-NEXT:  (func $1 (param $0 i32) (result i32)
-;; KEEP-NONE-SECONDARY-NEXT:   (call $0
+;; KEEP-NONE-SECONDARY-NEXT:  (func $foo (param $0 i32) (result i32)
+;; KEEP-NONE-SECONDARY-NEXT:   (call $bar
 ;; KEEP-NONE-SECONDARY-NEXT:    (i32.const 0)
 ;; KEEP-NONE-SECONDARY-NEXT:   )
 ;; KEEP-NONE-SECONDARY-NEXT:  )
@@ -60,12 +60,12 @@
 
 ;; KEEP-FOO-PRIMARY:      (module
 ;; KEEP-FOO-PRIMARY-NEXT:  (type $i32_=>_i32 (func (param i32) (result i32)))
-;; KEEP-FOO-PRIMARY-NEXT:  (import "placeholder" "1" (func $fimport$0 (param i32) (result i32)))
-;; KEEP-FOO-PRIMARY-NEXT:  (table $0 2 2 funcref)
-;; KEEP-FOO-PRIMARY-NEXT:  (elem (i32.const 0) $0 $fimport$0)
-;; KEEP-FOO-PRIMARY-NEXT:  (export "%foo" (func $0))
-;; KEEP-FOO-PRIMARY-NEXT:  (export "%table" (table $0))
-;; KEEP-FOO-PRIMARY-NEXT:  (func $0 (param $0 i32) (result i32)
+;; KEEP-FOO-PRIMARY-NEXT:  (import "placeholder" "1" (func $placeholder_1 (param i32) (result i32)))
+;; KEEP-FOO-PRIMARY-NEXT:  (table $table 2 2 funcref)
+;; KEEP-FOO-PRIMARY-NEXT:  (elem (i32.const 0) $foo $placeholder_1)
+;; KEEP-FOO-PRIMARY-NEXT:  (export "%foo" (func $foo))
+;; KEEP-FOO-PRIMARY-NEXT:  (export "%table" (table $table))
+;; KEEP-FOO-PRIMARY-NEXT:  (func $foo (param $0 i32) (result i32)
 ;; KEEP-FOO-PRIMARY-NEXT:   (call_indirect (type $i32_=>_i32)
 ;; KEEP-FOO-PRIMARY-NEXT:    (i32.const 0)
 ;; KEEP-FOO-PRIMARY-NEXT:    (i32.const 1)
@@ -75,11 +75,11 @@
 
 ;; KEEP-FOO-SECONDARY:      (module
 ;; KEEP-FOO-SECONDARY-NEXT:  (type $i32_=>_i32 (func (param i32) (result i32)))
-;; KEEP-FOO-SECONDARY-NEXT:  (import "primary" "%table" (table $timport$0 2 2 funcref))
-;; KEEP-FOO-SECONDARY-NEXT:  (import "primary" "%foo" (func $fimport$0 (param i32) (result i32)))
-;; KEEP-FOO-SECONDARY-NEXT:  (elem (i32.const 1) $0)
-;; KEEP-FOO-SECONDARY-NEXT:  (func $0 (param $0 i32) (result i32)
-;; KEEP-FOO-SECONDARY-NEXT:   (call $fimport$0
+;; KEEP-FOO-SECONDARY-NEXT:  (import "primary" "%table" (table $table 2 2 funcref))
+;; KEEP-FOO-SECONDARY-NEXT:  (import "primary" "%foo" (func $foo (param i32) (result i32)))
+;; KEEP-FOO-SECONDARY-NEXT:  (elem (i32.const 1) $bar)
+;; KEEP-FOO-SECONDARY-NEXT:  (func $bar (param $0 i32) (result i32)
+;; KEEP-FOO-SECONDARY-NEXT:   (call $foo
 ;; KEEP-FOO-SECONDARY-NEXT:    (i32.const 1)
 ;; KEEP-FOO-SECONDARY-NEXT:   )
 ;; KEEP-FOO-SECONDARY-NEXT:  )
@@ -90,12 +90,12 @@
 
 ;; KEEP-BAR-PRIMARY:      (module
 ;; KEEP-BAR-PRIMARY-NEXT:  (type $i32_=>_i32 (func (param i32) (result i32)))
-;; KEEP-BAR-PRIMARY-NEXT:  (import "placeholder" "0" (func $fimport$0 (param i32) (result i32)))
-;; KEEP-BAR-PRIMARY-NEXT:  (table $0 1 1 funcref)
-;; KEEP-BAR-PRIMARY-NEXT:  (elem (i32.const 0) $fimport$0)
-;; KEEP-BAR-PRIMARY-NEXT:  (export "%bar" (func $0))
-;; KEEP-BAR-PRIMARY-NEXT:  (export "%table" (table $0))
-;; KEEP-BAR-PRIMARY-NEXT:  (func $0 (param $0 i32) (result i32)
+;; KEEP-BAR-PRIMARY-NEXT:  (import "placeholder" "0" (func $placeholder_0 (param i32) (result i32)))
+;; KEEP-BAR-PRIMARY-NEXT:  (table $table 1 1 funcref)
+;; KEEP-BAR-PRIMARY-NEXT:  (elem (i32.const 0) $placeholder_0)
+;; KEEP-BAR-PRIMARY-NEXT:  (export "%bar" (func $bar))
+;; KEEP-BAR-PRIMARY-NEXT:  (export "%table" (table $table))
+;; KEEP-BAR-PRIMARY-NEXT:  (func $bar (param $0 i32) (result i32)
 ;; KEEP-BAR-PRIMARY-NEXT:   (call_indirect (type $i32_=>_i32)
 ;; KEEP-BAR-PRIMARY-NEXT:    (i32.const 1)
 ;; KEEP-BAR-PRIMARY-NEXT:    (i32.const 0)
@@ -105,11 +105,11 @@
 
 ;; KEEP-BAR-SECONDARY:      (module
 ;; KEEP-BAR-SECONDARY-NEXT:  (type $i32_=>_i32 (func (param i32) (result i32)))
-;; KEEP-BAR-SECONDARY-NEXT:  (import "primary" "%table" (table $timport$0 1 1 funcref))
-;; KEEP-BAR-SECONDARY-NEXT:  (import "primary" "%bar" (func $fimport$0 (param i32) (result i32)))
-;; KEEP-BAR-SECONDARY-NEXT:  (elem (i32.const 0) $0)
-;; KEEP-BAR-SECONDARY-NEXT:  (func $0 (param $0 i32) (result i32)
-;; KEEP-BAR-SECONDARY-NEXT:   (call $fimport$0
+;; KEEP-BAR-SECONDARY-NEXT:  (import "primary" "%table" (table $table 1 1 funcref))
+;; KEEP-BAR-SECONDARY-NEXT:  (import "primary" "%bar" (func $bar (param i32) (result i32)))
+;; KEEP-BAR-SECONDARY-NEXT:  (elem (i32.const 0) $foo)
+;; KEEP-BAR-SECONDARY-NEXT:  (func $foo (param $0 i32) (result i32)
+;; KEEP-BAR-SECONDARY-NEXT:   (call $bar
 ;; KEEP-BAR-SECONDARY-NEXT:    (i32.const 0)
 ;; KEEP-BAR-SECONDARY-NEXT:   )
 ;; KEEP-BAR-SECONDARY-NEXT:  )
@@ -121,21 +121,21 @@
 
 ;; KEEP-BOTH-PRIMARY:      (module
 ;; KEEP-BOTH-PRIMARY-NEXT:  (type $i32_=>_i32 (func (param i32) (result i32)))
-;; KEEP-BOTH-PRIMARY-NEXT:  (table $0 1 1 funcref)
-;; KEEP-BOTH-PRIMARY-NEXT:  (elem (i32.const 0) $0)
-;; KEEP-BOTH-PRIMARY-NEXT:  (export "%table" (table $0))
-;; KEEP-BOTH-PRIMARY-NEXT:  (func $0 (param $0 i32) (result i32)
-;; KEEP-BOTH-PRIMARY-NEXT:   (call $1
+;; KEEP-BOTH-PRIMARY-NEXT:  (table $table 1 1 funcref)
+;; KEEP-BOTH-PRIMARY-NEXT:  (elem (i32.const 0) $foo)
+;; KEEP-BOTH-PRIMARY-NEXT:  (export "%table" (table $table))
+;; KEEP-BOTH-PRIMARY-NEXT:  (func $foo (param $0 i32) (result i32)
+;; KEEP-BOTH-PRIMARY-NEXT:   (call $bar
 ;; KEEP-BOTH-PRIMARY-NEXT:    (i32.const 0)
 ;; KEEP-BOTH-PRIMARY-NEXT:   )
 ;; KEEP-BOTH-PRIMARY-NEXT:  )
-;; KEEP-BOTH-PRIMARY-NEXT:  (func $1 (param $0 i32) (result i32)
-;; KEEP-BOTH-PRIMARY-NEXT:   (call $0
+;; KEEP-BOTH-PRIMARY-NEXT:  (func $bar (param $0 i32) (result i32)
+;; KEEP-BOTH-PRIMARY-NEXT:   (call $foo
 ;; KEEP-BOTH-PRIMARY-NEXT:    (i32.const 1)
 ;; KEEP-BOTH-PRIMARY-NEXT:   )
 ;; KEEP-BOTH-PRIMARY-NEXT:  )
 ;; KEEP-BOTH-PRIMARY-NEXT: )
 
 ;; KEEP-BOTH-SECONDARY:      (module
-;; KEEP-BOTH-SECONDARY-NEXT:  (import "primary" "%table" (table $timport$0 1 1 funcref))
+;; KEEP-BOTH-SECONDARY-NEXT:  (import "primary" "%table" (table $table 1 1 funcref))
 ;; KEEP-BOTH-SECONDARY-NEXT: )
diff --git a/test/lit/wasm-split/minimized-exports.wast b/test/lit/wasm-split/minimized-exports.wast
new file mode 100644
index 000000000..a7c225550
--- /dev/null
+++ b/test/lit/wasm-split/minimized-exports.wast
@@ -0,0 +1,38 @@
+;; RUN: wasm-split %s --keep-funcs=foo,bar --export-prefix='%' -o1 %t.1.wasm -o2 %t.2.wasm
+;; RUN: wasm-dis %t.1.wasm | filecheck %s --check-prefix PRIMARY
+;; RUN: wasm-dis %t.2.wasm | filecheck %s --check-prefix SECONDARY
+
+;; PRIMARY:      (module
+;; PRIMARY-NEXT:   (type $none_=>_none (func))
+;; PRIMARY-NEXT:   (export "%a" (func $1))
+;; PRIMARY-NEXT:   (export "%b" (func $0))
+;; PRIMARY-NEXT:   (func $0
+;; PRIMARY-NEXT:     (nop)
+;; PRIMARY-NEXT:   )
+;; PRIMARY-NEXT:   (func $1
+;; PRIMARY-NEXT:     (nop)
+;; PRIMARY-NEXT:   )
+;; PRIMARY-NEXT: )
+
+;; SECONDARY:      (module
+;; SECONDARY-NEXT:   (type $none_=>_none (func))
+;; SECONDARY-NEXT:   (import "primary" "%a" (func $fimport$0))
+;; SECONDARY-NEXT:   (import "primary" "%b" (func $fimport$1))
+;; SECONDARY-NEXT:   (func $0
+;; SECONDARY-NEXT:     (call $fimport$1)
+;; SECONDARY-NEXT:     (call $fimport$0)
+;; SECONDARY-NEXT:   )
+;; SECONDARY-NEXT: )
+
+(module
+  (func $foo
+    (nop)
+  )
+  (func $bar
+    (nop)
+  )
+  (func $baz
+    (call $foo)
+    (call $bar)
+  )
+)