summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
Diffstat
-rw-r--r--src/passes/StringLowering.cpp64
-rw-r--r--src/passes/pass.cpp3
-rw-r--r--src/passes/passes.h1
-rw-r--r--test/lit/help/wasm-opt.test3
-rw-r--r--test/lit/help/wasm2js.test3
-rw-r--r--test/lit/passes/string-gathering.wast46
-rw-r--r--test/lit/passes/string-lowering.wast23
7 files changed, 139 insertions, 4 deletions
diff --git a/src/passes/StringLowering.cpp b/src/passes/StringLowering.cpp
index f880a50b2..31e41b9e8 100644
--- a/src/passes/StringLowering.cpp
+++ b/src/passes/StringLowering.cpp
@@ -21,17 +21,18 @@
// globals, avoiding them appearing in code that can run more than once (which
// can have overhead in VMs).
//
-// Building on that, an extended version of StringGathering will also replace
-// those new globals with imported globals of type externref, for use with the
-// string imports proposal. String operations will likewise need to be lowered.
-// TODO
+// StringLowering does the same, and also replaces those new globals with
+// imported globals of type externref, for use with the string imports proposal.
+// String operations will likewise need to be lowered. TODO
//
#include <algorithm>
#include "ir/module-utils.h"
#include "ir/names.h"
+#include "ir/type-updating.h"
#include "pass.h"
+#include "support/json.h"
#include "wasm-builder.h"
#include "wasm.h"
@@ -175,6 +176,61 @@ struct StringGathering : public Pass {
}
};
+struct StringLowering : public StringGathering {
+ void run(Module* module) override {
+ if (!module->features.has(FeatureSet::Strings)) {
+ return;
+ }
+
+ // First, run the gathering operation so all string.consts are in one place.
+ StringGathering::run(module);
+
+ // Lower the string.const globals into imports.
+ makeImports(module);
+
+ // Remove all HeapType::string etc. in favor of externref.
+ updateTypes(module);
+
+ // Disable the feature here after we lowered everything away.
+ module->features.disable(FeatureSet::Strings);
+ }
+
+ void makeImports(Module* module) {
+ Index importIndex = 0;
+ json::Value stringArray;
+ stringArray.setArray();
+ std::vector<Name> importedStrings;
+ for (auto& global : module->globals) {
+ if (global->init) {
+ if (auto* c = global->init->dynCast<StringConst>()) {
+ global->module = "string.const";
+ global->base = std::to_string(importIndex);
+ importIndex++;
+ global->init = nullptr;
+
+ auto str = json::Value::make(std::string(c->string.str).c_str());
+ stringArray.push_back(str);
+ }
+ }
+ }
+
+ // Add a custom section with the JSON.
+ std::stringstream stream;
+ stringArray.stringify(stream);
+ auto str = stream.str();
+ auto vec = std::vector<char>(str.begin(), str.end());
+ module->customSections.emplace_back(
+ CustomSection{"string.consts", std::move(vec)});
+ }
+
+ void updateTypes(Module* module) {
+ TypeMapper::TypeUpdates updates;
+ updates[HeapType::string] = HeapType::ext;
+ TypeMapper(*module, updates).map();
+ }
+};
+
Pass* createStringGatheringPass() { return new StringGathering(); }
+Pass* createStringLoweringPass() { return new StringLowering(); }
} // namespace wasm
diff --git a/src/passes/pass.cpp b/src/passes/pass.cpp
index 057642ea2..c00a5e706 100644
--- a/src/passes/pass.cpp
+++ b/src/passes/pass.cpp
@@ -478,6 +478,9 @@ void PassRegistry::registerPasses() {
registerPass("string-gathering",
"gathers wasm strings to globals",
createStringGatheringPass);
+ registerPass("string-lowering",
+ "lowers wasm strings and operations to imports",
+ createStringLoweringPass);
registerPass(
"strip", "deprecated; same as strip-debug", createStripDebugPass);
registerPass("stack-check",
diff --git a/src/passes/passes.h b/src/passes/passes.h
index 295772109..3f8b3fe6b 100644
--- a/src/passes/passes.h
+++ b/src/passes/passes.h
@@ -154,6 +154,7 @@ Pass* createSimplifyLocalsNoStructurePass();
Pass* createSimplifyLocalsNoTeeNoStructurePass();
Pass* createStackCheckPass();
Pass* createStringGatheringPass();
+Pass* createStringLoweringPass();
Pass* createStripDebugPass();
Pass* createStripDWARFPass();
Pass* createStripProducersPass();
diff --git a/test/lit/help/wasm-opt.test b/test/lit/help/wasm-opt.test
index 8732f5e27..5a207a1b0 100644
--- a/test/lit/help/wasm-opt.test
+++ b/test/lit/help/wasm-opt.test
@@ -469,6 +469,9 @@
;; CHECK-NEXT:
;; CHECK-NEXT: --string-gathering gathers wasm strings to globals
;; CHECK-NEXT:
+;; CHECK-NEXT: --string-lowering lowers wasm strings and
+;; CHECK-NEXT: operations to imports
+;; CHECK-NEXT:
;; CHECK-NEXT: --strip deprecated; same as strip-debug
;; CHECK-NEXT:
;; CHECK-NEXT: --strip-debug strip debug info (including the
diff --git a/test/lit/help/wasm2js.test b/test/lit/help/wasm2js.test
index 40d608857..43243b99a 100644
--- a/test/lit/help/wasm2js.test
+++ b/test/lit/help/wasm2js.test
@@ -428,6 +428,9 @@
;; CHECK-NEXT:
;; CHECK-NEXT: --string-gathering gathers wasm strings to globals
;; CHECK-NEXT:
+;; CHECK-NEXT: --string-lowering lowers wasm strings and
+;; CHECK-NEXT: operations to imports
+;; CHECK-NEXT:
;; CHECK-NEXT: --strip deprecated; same as strip-debug
;; CHECK-NEXT:
;; CHECK-NEXT: --strip-debug strip debug info (including the
diff --git a/test/lit/passes/string-gathering.wast b/test/lit/passes/string-gathering.wast
index 21fe358a3..657858fc0 100644
--- a/test/lit/passes/string-gathering.wast
+++ b/test/lit/passes/string-gathering.wast
@@ -1,9 +1,15 @@
;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
;; RUN: foreach %s %t wasm-opt --string-gathering -all -S -o - | filecheck %s
+;; RUN: foreach %s %t wasm-opt --string-lowering -all -S -o - | filecheck %s --check-prefix=LOWER
;; All the strings should be collected into globals and used from there. They
;; should also be sorted deterministically (alphabetically).
+;;
+;; LOWER also lowers away strings entirely, leaving only imports and a custom
+;; section (that part is tested in string-lowering.wast). It also removes all
+;; uses of the string heap type, leaving extern instead for the imported
+;; strings.
(module
;; Note that $global will be reused: no new global will be added for "foo".
@@ -19,6 +25,15 @@
(global $global (ref string) (string.const "foo"))
;; CHECK: (global $global2 stringref (global.get $string.const_bar))
+ ;; LOWER: (type $0 (func))
+
+ ;; LOWER: (import "string.const" "0" (global $string.const_bar (ref extern)))
+
+ ;; LOWER: (import "string.const" "1" (global $string.const_other (ref extern)))
+
+ ;; LOWER: (import "string.const" "2" (global $global (ref extern)))
+
+ ;; LOWER: (global $global2 externref (global.get $string.const_bar))
(global $global2 (ref null string) (string.const "bar"))
;; CHECK: (func $a (type $0)
@@ -29,6 +44,14 @@
;; CHECK-NEXT: (global.get $global)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
+ ;; LOWER: (func $a (type $0)
+ ;; LOWER-NEXT: (drop
+ ;; LOWER-NEXT: (global.get $string.const_bar)
+ ;; LOWER-NEXT: )
+ ;; LOWER-NEXT: (drop
+ ;; LOWER-NEXT: (global.get $global)
+ ;; LOWER-NEXT: )
+ ;; LOWER-NEXT: )
(func $a
(drop
(string.const "bar")
@@ -52,6 +75,20 @@
;; CHECK-NEXT: (global.get $global2)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
+ ;; LOWER: (func $b (type $0)
+ ;; LOWER-NEXT: (drop
+ ;; LOWER-NEXT: (global.get $string.const_bar)
+ ;; LOWER-NEXT: )
+ ;; LOWER-NEXT: (drop
+ ;; LOWER-NEXT: (global.get $string.const_other)
+ ;; LOWER-NEXT: )
+ ;; LOWER-NEXT: (drop
+ ;; LOWER-NEXT: (global.get $global)
+ ;; LOWER-NEXT: )
+ ;; LOWER-NEXT: (drop
+ ;; LOWER-NEXT: (global.get $global2)
+ ;; LOWER-NEXT: )
+ ;; LOWER-NEXT: )
(func $b
(drop
(string.const "bar")
@@ -74,23 +111,32 @@
;; Multiple possible reusable globals. Also test ignoring of imports.
(module
;; CHECK: (import "a" "b" (global $import (ref string)))
+ ;; LOWER: (import "a" "b" (global $import (ref extern)))
(import "a" "b" (global $import (ref string)))
;; CHECK: (global $global1 (ref string) (string.const "foo"))
(global $global1 (ref string) (string.const "foo"))
;; CHECK: (global $global2 (ref string) (global.get $global1))
+ ;; LOWER: (import "string.const" "0" (global $global1 (ref extern)))
+
+ ;; LOWER: (import "string.const" "1" (global $global4 (ref extern)))
+
+ ;; LOWER: (global $global2 (ref extern) (global.get $global1))
(global $global2 (ref string) (string.const "foo"))
;; CHECK: (global $global3 (ref string) (global.get $global1))
+ ;; LOWER: (global $global3 (ref extern) (global.get $global1))
(global $global3 (ref string) (string.const "foo"))
;; CHECK: (global $global4 (ref string) (string.const "bar"))
(global $global4 (ref string) (string.const "bar"))
;; CHECK: (global $global5 (ref string) (global.get $global4))
+ ;; LOWER: (global $global5 (ref extern) (global.get $global4))
(global $global5 (ref string) (string.const "bar"))
;; CHECK: (global $global6 (ref string) (global.get $global4))
+ ;; LOWER: (global $global6 (ref extern) (global.get $global4))
(global $global6 (ref string) (string.const "bar"))
)
diff --git a/test/lit/passes/string-lowering.wast b/test/lit/passes/string-lowering.wast
new file mode 100644
index 000000000..628092d1c
--- /dev/null
+++ b/test/lit/passes/string-lowering.wast
@@ -0,0 +1,23 @@
+;; This file checks the custom section that --string-lowering adds. The other
+;; operations are tested in string-gathering.wast (which is auto-updated, unlike
+;; this which is manual).
+
+;; RUN: foreach %s %t wasm-opt --string-lowering -all -S -o - | filecheck %s
+
+(module
+ (func $consts
+ (drop
+ (string.const "foo")
+ )
+ (drop
+ (string.const "bar")
+ )
+ (drop
+ (string.const "foo")
+ )
+ )
+)
+
+;; The custom section should contain foo and bar, and foo only once.
+;; CHECK: custom section "string.consts", size 13, contents: "[\"bar\",\"foo\"]"
+
generated by cgit v1.2.3 (git 2.39.1) at 2025-04-09 20:17:53 +0000