[WebAssembly] MC: Fix for address taken aliases
Previously, taking the address for an alias would result in:
"Symbol not found in table index space"
Increase test coverage for weak aliases.
This code should be more efficient too as it avoids building
the `IsAddressTaken` set.
Differential Revision: https://reviews.llvm.org/D41510
llvm-svn: 321384
diff --git a/llvm/lib/MC/WasmObjectWriter.cpp b/llvm/lib/MC/WasmObjectWriter.cpp
index 310b7cd..0f0b645 100644
--- a/llvm/lib/MC/WasmObjectWriter.cpp
+++ b/llvm/lib/MC/WasmObjectWriter.cpp
@@ -553,7 +553,7 @@
case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
if (!IndirectSymbolIndices.count(RelEntry.Symbol))
- report_fatal_error("symbol not found table index space: " +
+ report_fatal_error("symbol not found in table index space: " +
RelEntry.Symbol->getName());
return IndirectSymbolIndices[RelEntry.Symbol];
case wasm::R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
@@ -562,7 +562,7 @@
case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB:
case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32:
if (!SymbolIndices.count(RelEntry.Symbol))
- report_fatal_error("symbol not found function/global index space: " +
+ report_fatal_error("symbol not found in function/global index space: " +
RelEntry.Symbol->getName());
return SymbolIndices[RelEntry.Symbol];
case wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB:
@@ -994,33 +994,10 @@
SmallVector<WasmExport, 4> Exports;
SmallVector<std::pair<StringRef, uint32_t>, 4> SymbolFlags;
SmallVector<std::pair<uint16_t, uint32_t>, 2> InitFuncs;
- SmallPtrSet<const MCSymbolWasm *, 4> IsAddressTaken;
unsigned NumFuncImports = 0;
SmallVector<WasmDataSegment, 4> DataSegments;
uint32_t DataSize = 0;
- // Populate the IsAddressTaken set.
- for (const WasmRelocationEntry &RelEntry : CodeRelocations) {
- switch (RelEntry.Type) {
- case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
- case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB:
- IsAddressTaken.insert(RelEntry.Symbol);
- break;
- default:
- break;
- }
- }
- for (const WasmRelocationEntry &RelEntry : DataRelocations) {
- switch (RelEntry.Type) {
- case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
- case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32:
- IsAddressTaken.insert(RelEntry.Symbol);
- break;
- default:
- break;
- }
- }
-
// In the special .global_variables section, we've encoded global
// variables used by the function. Translate them into the Globals
// list.
@@ -1217,14 +1194,7 @@
}
DEBUG(dbgs() << " -> function index: " << Index << "\n");
-
- // If needed, prepare the function to be called indirectly.
- if (IsAddressTaken.count(&WS) != 0) {
- IndirectSymbolIndices[&WS] = TableElems.size();
- DEBUG(dbgs() << " -> adding to table: " << TableElems.size() << "\n");
- TableElems.push_back(Index);
- }
- } else {
+ } else {
if (WS.isTemporary() && !WS.getSize())
continue;
@@ -1288,7 +1258,6 @@
uint32_t Index = SymbolIndices.find(ResolvedSym)->second;
DEBUG(dbgs() << " -> index:" << Index << "\n");
- //SymbolIndices[&WS] = Index;
WasmExport Export;
Export.FieldName = WS.getName();
Export.Index = Index;
@@ -1303,12 +1272,34 @@
SymbolFlags.emplace_back(WS.getName(), wasm::WASM_SYMBOL_BINDING_LOCAL);
}
- // Add types for indirect function calls.
- for (const WasmRelocationEntry &Fixup : CodeRelocations) {
- if (Fixup.Type != wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB)
- continue;
+ {
+ auto HandleReloc = [&](const WasmRelocationEntry &Rel) {
+ // Functions referenced by a relocation need to prepared to be called
+ // indirectly.
+ const MCSymbolWasm& WS = *Rel.Symbol;
+ if (WS.isFunction() && IndirectSymbolIndices.count(&WS) == 0) {
+ switch (Rel.Type) {
+ case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
+ case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
+ case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32:
+ case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB: {
+ uint32_t Index = SymbolIndices.find(&WS)->second;
+ IndirectSymbolIndices[&WS] = TableElems.size();
+ DEBUG(dbgs() << " -> adding to table: " << TableElems.size() << "\n");
+ TableElems.push_back(Index);
+ registerFunctionType(WS);
+ break;
+ }
+ default:
+ break;
+ }
+ }
+ };
- registerFunctionType(*Fixup.Symbol);
+ for (const WasmRelocationEntry &RelEntry : CodeRelocations)
+ HandleReloc(RelEntry);
+ for (const WasmRelocationEntry &RelEntry : DataRelocations)
+ HandleReloc(RelEntry);
}
// Translate .init_array section contents into start functions.