[lld] r319813 - [WebAssembly] Improve support linker synthetic symbols
Sam Clegg via llvm-commits
llvm-commits at lists.llvm.org
Tue Dec 5 11:05:45 PST 2017
Author: sbc
Date: Tue Dec 5 11:05:45 2017
New Revision: 319813
URL: http://llvm.org/viewvc/llvm-project?rev=319813&view=rev
Log:
[WebAssembly] Improve support linker synthetic symbols
This is part of larger change to add synthetic symbols
for section start/end points and init/fini_array:
https://reviews.llvm.org/D40760
Allows synthetic global symbols to have an explicitly set
virtual address.
Differential Revision: https://reviews.llvm.org/D40843
Modified:
lld/trunk/wasm/Config.h
lld/trunk/wasm/Driver.cpp
lld/trunk/wasm/Symbols.cpp
lld/trunk/wasm/Symbols.h
lld/trunk/wasm/Writer.cpp
Modified: lld/trunk/wasm/Config.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/Config.h?rev=319813&r1=319812&r2=319813&view=diff
==============================================================================
--- lld/trunk/wasm/Config.h (original)
+++ lld/trunk/wasm/Config.h Tue Dec 5 11:05:45 2017
@@ -39,7 +39,8 @@ struct Configuration {
llvm::StringSet<> AllowUndefinedSymbols;
std::vector<llvm::StringRef> SearchPaths;
- std::vector<std::pair<Symbol *, WasmGlobal>> SyntheticGlobals;
+ std::vector<Symbol *> SyntheticGlobals;
+ Symbol *StackPointerSymbol = nullptr;
};
// The only instance of Configuration struct.
Modified: lld/trunk/wasm/Driver.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/Driver.cpp?rev=319813&r1=319812&r2=319813&view=diff
==============================================================================
--- lld/trunk/wasm/Driver.cpp (original)
+++ lld/trunk/wasm/Driver.cpp Tue Dec 5 11:05:45 2017
@@ -138,17 +138,12 @@ static Optional<std::string> findFile(St
// Wasm global are used in relocatable object files to model symbol imports
// and exports. In the final executable the only use of wasm globals is
// for the exlicit stack pointer (__stack_pointer).
-static void addSyntheticGlobal(StringRef Name, int32_t Value) {
+static Symbol* addSyntheticGlobal(StringRef Name, int32_t Value) {
log("injecting global: " + Name);
Symbol *S = Symtab->addDefinedGlobal(Name);
- S->setOutputIndex(Config->SyntheticGlobals.size());
-
- WasmGlobal Global;
- Global.Mutable = true;
- Global.Type = WASM_TYPE_I32;
- Global.InitExpr.Opcode = WASM_OPCODE_I32_CONST;
- Global.InitExpr.Value.Int32 = Value;
- Config->SyntheticGlobals.emplace_back(S, Global);
+ S->setVirtualAddress(Value);
+ Config->SyntheticGlobals.emplace_back(S);
+ return S;
}
// Inject a new undefined symbol into the link. This will cause the link to
@@ -285,7 +280,7 @@ void LinkerDriver::link(ArrayRef<const c
static WasmSignature Signature = {{}, WASM_TYPE_NORESULT};
addSyntheticUndefinedFunction(Config->Entry, &Signature);
- addSyntheticGlobal("__stack_pointer", 0);
+ Config->StackPointerSymbol = addSyntheticGlobal("__stack_pointer", 0);
}
createFiles(Args);
Modified: lld/trunk/wasm/Symbols.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/Symbols.cpp?rev=319813&r1=319812&r2=319813&view=diff
==============================================================================
--- lld/trunk/wasm/Symbols.cpp (original)
+++ lld/trunk/wasm/Symbols.cpp Tue Dec 5 11:05:45 2017
@@ -41,6 +41,8 @@ uint32_t Symbol::getVirtualAddress() con
DEBUG(dbgs() << "getVirtualAddress: " << getName() << "\n");
if (isUndefined())
return UINT32_MAX;
+ if (VirtualAddress.hasValue())
+ return VirtualAddress.getValue();
assert(Sym != nullptr);
ObjFile *Obj = cast<ObjFile>(File);
@@ -57,6 +59,11 @@ uint32_t Symbol::getOutputIndex() const
return OutputIndex.getValue();
}
+void Symbol::setVirtualAddress(uint32_t Value) {
+ DEBUG(dbgs() << "setVirtualAddress " << Name << " -> " << Value << "\n");
+ VirtualAddress = Value;
+}
+
void Symbol::setOutputIndex(uint32_t Index) {
DEBUG(dbgs() << "setOutputIndex " << Name << " -> " << Index << "\n");
assert(!hasOutputIndex());
Modified: lld/trunk/wasm/Symbols.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/Symbols.h?rev=319813&r1=319812&r2=319813&view=diff
==============================================================================
--- lld/trunk/wasm/Symbols.h (original)
+++ lld/trunk/wasm/Symbols.h Tue Dec 5 11:05:45 2017
@@ -77,12 +77,14 @@ public:
uint32_t getVirtualAddress() const;
// Returns true if an output index has been set for this symbol
- bool hasOutputIndex() { return OutputIndex.hasValue(); }
+ bool hasOutputIndex() const { return OutputIndex.hasValue(); }
// Set the output index of the symbol (in the function or global index
// space of the output object.
void setOutputIndex(uint32_t Index);
+ void setVirtualAddress(uint32_t VA);
+
void update(Kind K, InputFile *F = nullptr, const WasmSymbol *Sym = nullptr,
const InputSegment *Segment = nullptr,
const WasmSignature *Sig = nullptr);
@@ -105,6 +107,7 @@ protected:
const WasmSymbol *Sym = nullptr;
const InputSegment *Segment = nullptr;
llvm::Optional<uint32_t> OutputIndex;
+ llvm::Optional<uint32_t> VirtualAddress;
const WasmSignature *FunctionType;
};
Modified: lld/trunk/wasm/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/Writer.cpp?rev=319813&r1=319812&r2=319813&view=diff
==============================================================================
--- lld/trunk/wasm/Writer.cpp (original)
+++ lld/trunk/wasm/Writer.cpp Tue Dec 5 11:05:45 2017
@@ -149,7 +149,7 @@ void Writer::createImportSection() {
writeUleb128(OS, NumImports, "import count");
- for (Symbol *Sym : FunctionImports) {
+ for (const Symbol *Sym : FunctionImports) {
WasmImport Import;
Import.Module = "env";
Import.Field = Sym->getName();
@@ -169,7 +169,7 @@ void Writer::createImportSection() {
writeImport(OS, Import);
}
- for (Symbol *Sym : GlobalImports) {
+ for (const Symbol *Sym : GlobalImports) {
WasmImport Import;
Import.Module = "env";
Import.Field = Sym->getName();
@@ -221,8 +221,12 @@ void Writer::createGlobalSection() {
raw_ostream &OS = Section->getStream();
writeUleb128(OS, NumGlobals, "global count");
- for (auto &Pair : Config->SyntheticGlobals) {
- WasmGlobal &Global = Pair.second;
+ for (const Symbol *Sym : Config->SyntheticGlobals) {
+ WasmGlobal Global;
+ Global.Type = WASM_TYPE_I32;
+ Global.Mutable = Sym == Config->StackPointerSymbol;
+ Global.InitExpr.Opcode = WASM_OPCODE_I32_CONST;
+ Global.InitExpr.Value.Int32 = Sym->getVirtualAddress();
writeGlobal(OS, Global);
}
@@ -507,7 +511,7 @@ void Writer::layoutMemory() {
debugPrint("mem: stack size = %d\n", Config->ZStackSize);
debugPrint("mem: stack base = %d\n", MemoryPtr);
MemoryPtr += Config->ZStackSize;
- Config->SyntheticGlobals[0].second.InitExpr.Value.Int32 = MemoryPtr;
+ Config->StackPointerSymbol->setVirtualAddress(MemoryPtr);
debugPrint("mem: stack top = %d\n", MemoryPtr);
}
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