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-rw-r--r--src/passes/StringLowering.cpp18
-rw-r--r--test/lit/passes/string-gathering.wast87
2 files changed, 84 insertions, 21 deletions
diff --git a/src/passes/StringLowering.cpp b/src/passes/StringLowering.cpp
index 081db6068..66841f299 100644
--- a/src/passes/StringLowering.cpp
+++ b/src/passes/StringLowering.cpp
@@ -111,18 +111,15 @@ struct StringGathering : public Pass {
// then we can just use that as the global for that string. This avoids
// repeated executions of the pass adding more and more globals.
//
- // Note that we don't note these in newNames: They are already in the right
- // sorted position, before any uses, as we use the first of them for each
- // string. Only actually new names need sorting.
- //
// Any time we reuse a global, we must not modify its body (or else we'd
// replace the global that all others read from); we note them here and
// avoid them in replaceStrings later to avoid such trampling.
std::unordered_set<Expression**> stringPtrsToPreserve;
void addGlobals(Module* module) {
- // Note all the new names we create for the sorting later.
- std::unordered_set<Name> newNames;
+ // The names of the globals that define a string. Such globals may be
+ // referred to by others, and so we will need to sort them, later.
+ std::unordered_set<Name> definingNames;
// Find globals to reuse (see comment on stringPtrsToPreserve for context).
for (auto& global : module->globals) {
@@ -143,7 +140,8 @@ struct StringGathering : public Pass {
for (Index i = 0; i < strings.size(); i++) {
auto& globalName = stringToGlobalName[strings[i]];
if (globalName.is()) {
- // We are reusing a global for this one.
+ // We are reusing a global for this one, with its existing name.
+ definingNames.insert(globalName);
continue;
}
@@ -160,14 +158,14 @@ struct StringGathering : public Pass {
auto name = Names::getValidGlobalName(
*module, std::string("string.const_") + std::string(escaped.str()));
globalName = name;
- newNames.insert(name);
+ definingNames.insert(name);
auto* stringConst = builder.makeStringConst(string);
auto global =
builder.makeGlobal(name, nnstringref, stringConst, Builder::Immutable);
module->addGlobal(std::move(global));
}
- // Sort our new globals to the start, as other global initializers may use
+ // Sort defining globals to the start, as other global initializers may use
// them (and it would be invalid for us to appear after a use). This sort is
// a simple way to ensure that we validate, but it may be unoptimal (we
// leave that for reorder-globals).
@@ -175,7 +173,7 @@ struct StringGathering : public Pass {
module->globals.begin(),
module->globals.end(),
[&](const std::unique_ptr<Global>& a, const std::unique_ptr<Global>& b) {
- return newNames.count(a->name) && !newNames.count(b->name);
+ return definingNames.count(a->name) && !definingNames.count(b->name);
});
}
diff --git a/test/lit/passes/string-gathering.wast b/test/lit/passes/string-gathering.wast
index a6243c238..cf29c787f 100644
--- a/test/lit/passes/string-gathering.wast
+++ b/test/lit/passes/string-gathering.wast
@@ -17,13 +17,13 @@
;; CHECK: (type $0 (func))
+ ;; CHECK: (global $global (ref string) (string.const "foo"))
+ (global $global (ref string) (string.const "foo"))
+
;; CHECK: (global $"string.const_\"bar\"" (ref string) (string.const "bar"))
;; CHECK: (global $"string.const_\"other\"" (ref string) (string.const "other"))
- ;; CHECK: (global $global (ref string) (string.const "foo"))
- (global $global (ref string) (string.const "foo"))
-
;; CHECK: (global $global2 stringref (global.get $"string.const_\"bar\""))
;; LOWER: (type $0 (array (mut i16)))
@@ -45,11 +45,11 @@
;; LOWER: (type $9 (func (param externref i32 i32) (result (ref extern))))
- ;; LOWER: (import "string.const" "0" (global $"string.const_\"bar\"" (ref extern)))
+ ;; LOWER: (import "string.const" "0" (global $global (ref extern)))
- ;; LOWER: (import "string.const" "1" (global $"string.const_\"other\"" (ref extern)))
+ ;; LOWER: (import "string.const" "1" (global $"string.const_\"bar\"" (ref extern)))
- ;; LOWER: (import "string.const" "2" (global $global (ref extern)))
+ ;; LOWER: (import "string.const" "2" (global $"string.const_\"other\"" (ref extern)))
;; LOWER: (import "wasm:js-string" "fromCharCodeArray" (func $fromCharCodeArray (type $3) (param (ref null $0) i32 i32) (result (ref extern))))
@@ -165,17 +165,19 @@
;; LOWER: (type $8 (func (param externref i32 i32) (result (ref extern))))
+ ;; LOWER: (import "string.const" "0" (global $global1 (ref extern)))
+
+ ;; LOWER: (import "string.const" "1" (global $global4 (ref extern)))
+
;; 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)))
+ ;; CHECK: (global $global4 (ref string) (string.const "bar"))
+ ;; CHECK: (global $global2 (ref string) (global.get $global1))
;; LOWER: (import "wasm:js-string" "fromCharCodeArray" (func $fromCharCodeArray (type $2) (param (ref null $0) i32 i32) (result (ref extern))))
;; LOWER: (import "wasm:js-string" "fromCodePoint" (func $fromCodePoint (type $3) (param i32) (result (ref extern))))
@@ -201,7 +203,6 @@
;; 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))
@@ -279,3 +280,67 @@
)
)
)
+
+;; A module where a string (in this case the empty string) appears twice, so we
+;; will use a single global for both. The first use of the string appears in a
+;; nested position, inside a struct constructor, so we cannot use that one as
+;; our defining global, but there is an appropriate global after it. We must be
+;; careful to then sort the globals, as $string must then appear before $struct.
+(module
+ ;; CHECK: (type $struct (struct (field stringref)))
+ ;; LOWER: (type $0 (array (mut i16)))
+
+ ;; LOWER: (type $struct (struct (field externref)))
+ (type $struct (struct (field stringref)))
+
+ ;; CHECK: (global $string (ref string) (string.const ""))
+
+ ;; CHECK: (global $struct (ref $struct) (struct.new $struct
+ ;; CHECK-NEXT: (global.get $string)
+ ;; CHECK-NEXT: ))
+ ;; LOWER: (type $2 (func (param externref externref) (result i32)))
+
+ ;; LOWER: (type $3 (func (param (ref null $0) i32 i32) (result (ref extern))))
+
+ ;; LOWER: (type $4 (func (param i32) (result (ref extern))))
+
+ ;; LOWER: (type $5 (func (param externref externref) (result (ref extern))))
+
+ ;; LOWER: (type $6 (func (param externref (ref null $0) i32) (result i32)))
+
+ ;; LOWER: (type $7 (func (param externref) (result i32)))
+
+ ;; LOWER: (type $8 (func (param externref i32) (result i32)))
+
+ ;; LOWER: (type $9 (func (param externref i32 i32) (result (ref extern))))
+
+ ;; LOWER: (import "string.const" "0" (global $string (ref extern)))
+
+ ;; LOWER: (import "wasm:js-string" "fromCharCodeArray" (func $fromCharCodeArray (type $3) (param (ref null $0) i32 i32) (result (ref extern))))
+
+ ;; LOWER: (import "wasm:js-string" "fromCodePoint" (func $fromCodePoint (type $4) (param i32) (result (ref extern))))
+
+ ;; LOWER: (import "wasm:js-string" "concat" (func $concat (type $5) (param externref externref) (result (ref extern))))
+
+ ;; LOWER: (import "wasm:js-string" "intoCharCodeArray" (func $intoCharCodeArray (type $6) (param externref (ref null $0) i32) (result i32)))
+
+ ;; LOWER: (import "wasm:js-string" "equals" (func $equals (type $2) (param externref externref) (result i32)))
+
+ ;; LOWER: (import "wasm:js-string" "compare" (func $compare (type $2) (param externref externref) (result i32)))
+
+ ;; LOWER: (import "wasm:js-string" "length" (func $length (type $7) (param externref) (result i32)))
+
+ ;; LOWER: (import "wasm:js-string" "charCodeAt" (func $charCodeAt (type $8) (param externref i32) (result i32)))
+
+ ;; LOWER: (import "wasm:js-string" "substring" (func $substring (type $9) (param externref i32 i32) (result (ref extern))))
+
+ ;; LOWER: (global $struct (ref $struct) (struct.new $struct
+ ;; LOWER-NEXT: (global.get $string)
+ ;; LOWER-NEXT: ))
+ (global $struct (ref $struct) (struct.new $struct
+ (string.const "")
+ ))
+
+ (global $string (ref string) (string.const ""))
+)
+
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