[WebAssembly] MC: Fix crash in getProvitionalValue on weak references
- Create helper function for resolving weak references.
- Add test that preproduces the crash.
Differential Revision: https://reviews.llvm.org/D37916
llvm-svn: 313381
diff --git a/llvm/lib/MC/WasmObjectWriter.cpp b/llvm/lib/MC/WasmObjectWriter.cpp
index 4093b55..1ae292e 100644
--- a/llvm/lib/MC/WasmObjectWriter.cpp
+++ b/llvm/lib/MC/WasmObjectWriter.cpp
@@ -477,13 +477,22 @@
Stream.pwrite((char *)Buffer, sizeof(Buffer), Offset);
}
+static const MCSymbolWasm* ResolveSymbol(const MCSymbolWasm& Symbol) {
+ if (Symbol.isVariable()) {
+ const MCExpr *Expr = Symbol.getVariableValue();
+ auto *Inner = cast<MCSymbolRefExpr>(Expr);
+ return cast<MCSymbolWasm>(&Inner->getSymbol());
+ }
+ return &Symbol;
+}
+
// Compute a value to write into the code at the location covered
// by RelEntry. This value isn't used by the static linker, since
// we have addends; it just serves to make the code more readable
// and to make standalone wasm modules directly usable.
uint32_t
WasmObjectWriter::getProvisionalValue(const WasmRelocationEntry &RelEntry) {
- const MCSymbolWasm *Sym = RelEntry.Symbol;
+ const MCSymbolWasm *Sym = ResolveSymbol(*RelEntry.Symbol);
// For undefined symbols, use a hopefully invalid value.
if (!Sym->isDefined(/*SetUsed=*/false))
@@ -934,16 +943,9 @@
assert(Symbol.isFunction());
WasmFunctionType F;
- if (Symbol.isVariable()) {
- const MCExpr *Expr = Symbol.getVariableValue();
- auto *Inner = cast<MCSymbolRefExpr>(Expr);
- const auto *ResolvedSym = cast<MCSymbolWasm>(&Inner->getSymbol());
- F.Returns = ResolvedSym->getReturns();
- F.Params = ResolvedSym->getParams();
- } else {
- F.Returns = Symbol.getReturns();
- F.Params = Symbol.getParams();
- }
+ const MCSymbolWasm* ResolvedSym = ResolveSymbol(Symbol);
+ F.Returns = ResolvedSym->getReturns();
+ F.Params = ResolvedSym->getParams();
auto Pair =
FunctionTypeIndices.insert(std::make_pair(F, FunctionTypes.size()));
@@ -1255,11 +1257,9 @@
continue;
assert(S.isDefined(/*SetUsed=*/false));
- const auto &WS = static_cast<const MCSymbolWasm &>(S);
// Find the target symbol of this weak alias and export that index
- const MCExpr *Expr = WS.getVariableValue();
- auto *Inner = cast<MCSymbolRefExpr>(Expr);
- const auto *ResolvedSym = cast<MCSymbolWasm>(&Inner->getSymbol());
+ const auto &WS = static_cast<const MCSymbolWasm &>(S);
+ const MCSymbolWasm *ResolvedSym = ResolveSymbol(WS);
DEBUG(dbgs() << WS.getName() << ": weak alias of '" << *ResolvedSym << "'\n");
assert(SymbolIndices.count(ResolvedSym) > 0);
uint32_t Index = SymbolIndices.find(ResolvedSym)->second;