[lld][WebAssembly] Fix check for implicitly exported mutable globals #160966
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This change is designed to avoid exporting mutable globals in the case when mutable globals are not available. However, it was being applied in all cases even when mutable globals was enabled.
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@llvm/pr-subscribers-lld-wasm @llvm/pr-subscribers-lld Author: Sam Clegg (sbc100) ChangesThis change is designed to avoid exporting mutable globals in the case when mutable globals are not available. However, it was being applied in all cases even when mutable globals was enabled. Full diff: https://github.com/llvm/llvm-project/pull/160966.diff 2 Files Affected:
diff --git a/lld/test/wasm/mutable-global-exports.s b/lld/test/wasm/mutable-global-exports.s
index 4ffaf0a6cbaf0..1c10e92083b5c 100644
--- a/lld/test/wasm/mutable-global-exports.s
+++ b/lld/test/wasm/mutable-global-exports.s
@@ -73,6 +73,9 @@ _start:
# CHECK-ALL-NEXT: - Name: __wasm_call_ctors
# CHECK-ALL-NEXT: Kind: FUNCTION
# CHECK-ALL-NEXT: Index: 0
+# CHECK-ALL-NEXT: - Name: __stack_pointer
+# CHECK-ALL-NEXT: Kind: GLOBAL
+# CHECK-ALL-NEXT: Index: 0
# CHECK-ALL-NEXT: - Name: _start
# CHECK-ALL-NEXT: Kind: FUNCTION
# CHECK-ALL-NEXT: Index: 1
diff --git a/lld/wasm/Writer.cpp b/lld/wasm/Writer.cpp
index 0d36893653110..9a5b56fc52e2f 100644
--- a/lld/wasm/Writer.cpp
+++ b/lld/wasm/Writer.cpp
@@ -784,6 +784,9 @@ void Writer::calculateExports() {
unsigned globalIndex =
out.importSec->getNumImportedGlobals() + out.globalSec->numGlobals();
+ bool hasMutableGlobals =
+ out.targetFeaturesSec->features.count("mutable-globals") > 0;
+
for (Symbol *sym : symtab->symbols()) {
if (!sym->isExported())
continue;
@@ -801,7 +804,8 @@ void Writer::calculateExports() {
}
export_ = {name, WASM_EXTERNAL_FUNCTION, f->getExportedFunctionIndex()};
} else if (auto *g = dyn_cast<DefinedGlobal>(sym)) {
- if (g->getGlobalType()->Mutable && !g->getFile() && !g->forceExport) {
+ if (!hasMutableGlobals && g->getGlobalType()->Mutable && !g->getFile() &&
+ !g->isExportedExplicit()) {
// Avoid exporting mutable globals are linker synthesized (e.g.
// __stack_pointer or __tls_base) unless they are explicitly exported
// from the command line.
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So before we were basically just never exporting the stack pointer when EXPORT_ALL was set, and now we should be when mutable globals is available? |
Yes, exactly. |
dschuff
approved these changes
Sep 27, 2025
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/186/builds/12727 Here is the relevant piece of the build log for the reference |
mahesh-attarde
pushed a commit
to mahesh-attarde/llvm-project
that referenced
this pull request
Oct 3, 2025
…lvm#160966) This check is designed to avoid exporting mutable globals in the case when mutable globals are not available. However, it was being applied in all cases even when mutable globals was enabled. This error is particularly bad since mutable-globals have been enabled in default CPU for a while now, meaning that this condition should not be firing in the wild very often.
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This check is designed to avoid exporting mutable globals in the case when mutable globals are not available. However, it was being applied in all cases even when mutable globals was enabled.
This error is particularly bad since mutable-globals have been enabled in default CPU for a while now, meaning that this condition should not be firing in the wild very often.