diff options
| -rw-r--r-- | src/passes/Precompute.cpp | 6 | ||||
| -rw-r--r-- | src/passes/SimplifyGlobals.cpp | 22 | ||||
| -rw-r--r-- | test/lit/passes/precompute-gc.wast | 8 |
3 files changed, 9 insertions, 27 deletions
diff --git a/src/passes/Precompute.cpp b/src/passes/Precompute.cpp index 89e618ab3..5baf2331f 100644 --- a/src/passes/Precompute.cpp +++ b/src/passes/Precompute.cpp @@ -799,11 +799,9 @@ private: if (type.isFunction()) { return true; } - // We can emit a StringConst for a string constant in principle, but we do - // not want to as that might cause more allocations to happen. See similar - // code in SimplifyGlobals. + // We can emit a StringConst for a string constant. if (type.isString()) { - return false; + return true; } // All other reference types cannot be precomputed. Even an immutable GC // reference is not currently something this pass can handle, as it will diff --git a/src/passes/SimplifyGlobals.cpp b/src/passes/SimplifyGlobals.cpp index a7d8c3487..3baec4409 100644 --- a/src/passes/SimplifyGlobals.cpp +++ b/src/passes/SimplifyGlobals.cpp @@ -52,20 +52,6 @@ namespace wasm { namespace { -// Checks if an expression is a constant, and one that we can copy without -// downsides. This is the set of constant values that we will inline from -// globals. -bool isCopyableConstant(Expression* curr) { - // Anything that is truly constant is suitable for us, *except* for string - // constants, which in VMs may be implemented not as a constant but as an - // allocation. We prefer to keep string.const in globals where any such - // allocation only happens once (note that that makes them equivalent to - // strings imported from JS, which would be in imported globals, which are - // similarly not optimizable). - // TODO: revisit this if/when VMs implement and optimize string.const. - return Properties::isConstantExpression(curr) && !curr->is<StringConst>(); -} - struct GlobalInfo { // Whether the global is imported and exported. bool imported = false; @@ -372,7 +358,7 @@ struct ConstantGlobalApplier void visitExpression(Expression* curr) { if (auto* set = curr->dynCast<GlobalSet>()) { - if (isCopyableConstant(set->value)) { + if (Properties::isConstantExpression(set->value)) { currConstantGlobals[set->name] = getLiteralsFromConstExpression(set->value); } else { @@ -383,7 +369,7 @@ struct ConstantGlobalApplier // Check if the global is known to be constant all the time. if (constantGlobals->count(get->name)) { auto* global = getModule()->getGlobal(get->name); - assert(isCopyableConstant(global->init)); + assert(Properties::isConstantExpression(global->init)); replaceCurrent(ExpressionManipulator::copy(global->init, *getModule())); replaced = true; return; @@ -685,7 +671,7 @@ struct SimplifyGlobals : public Pass { // go, as well as applying them where possible. for (auto& global : module->globals) { if (!global->imported()) { - if (isCopyableConstant(global->init)) { + if (Properties::isConstantExpression(global->init)) { constantGlobals[global->name] = getLiteralsFromConstExpression(global->init); } else { @@ -709,7 +695,7 @@ struct SimplifyGlobals : public Pass { NameSet constantGlobals; for (auto& global : module->globals) { if (!global->mutable_ && !global->imported() && - isCopyableConstant(global->init)) { + Properties::isConstantExpression(global->init)) { constantGlobals.insert(global->name); } } diff --git a/test/lit/passes/precompute-gc.wast b/test/lit/passes/precompute-gc.wast index 603788f8c..8d4b56ce7 100644 --- a/test/lit/passes/precompute-gc.wast +++ b/test/lit/passes/precompute-gc.wast @@ -1021,10 +1021,10 @@ ;; CHECK-NEXT: (string.const "hello, world") ;; CHECK-NEXT: ) ;; CHECK-NEXT: (call $strings - ;; CHECK-NEXT: (local.get $s) + ;; CHECK-NEXT: (string.const "hello, world") ;; CHECK-NEXT: ) ;; CHECK-NEXT: (call $strings - ;; CHECK-NEXT: (local.get $s) + ;; CHECK-NEXT: (string.const "hello, world") ;; CHECK-NEXT: ) ;; CHECK-NEXT: ) (func $strings (param $param (ref string)) @@ -1032,9 +1032,7 @@ (local.set $s (string.const "hello, world") ) - ;; The constant string could be propagated twice, to both of these calls, but - ;; we do not do so as it might cause more allocations to happen. - ;; TODO if VMs optimize that, handle it + ;; The constant string should be propagated twice, to both of these calls. (call $strings (local.get $s) ) |