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-rw-r--r--src/wasm-linker.h255
1 files changed, 6 insertions, 249 deletions
diff --git a/src/wasm-linker.h b/src/wasm-linker.h
index ceb948c4e..9929a6f70 100644
--- a/src/wasm-linker.h
+++ b/src/wasm-linker.h
@@ -21,19 +21,14 @@
// is no merging of multiple modules). Currently this is only inteded to turn
// a .s file produced by LLVM into a usable wast file.
-
#ifndef WASM_WASM_LINK_H
#define WASM_WASM_LINK_H
#include "support/utilities.h"
#include "wasm.h"
-#include "wasm-printing.h"
namespace wasm {
-cashew::IString EMSCRIPTEN_ASM_CONST("emscripten_asm_const");
-
-
// Wasm module linking/layout information
class Linker {
public:
@@ -90,6 +85,9 @@ class Linker {
return address;
}
+ // Allocate space for a stack pointer and (if stackAllocation > 0) set up a
+ // relocation for it to point to the top of the stack.
+ void placeStackPointer(size_t stackAllocation);
void addGlobal(Name name) {
globls.push_back(name);
}
@@ -131,232 +129,13 @@ class Linker {
// Allocate the user stack, set up the initial memory size of the module, lay
// out the linear memory, process the relocations, and set up the indirect
// function table.
- void layout() {
- // Place the stack after the user's static data, to keep those addresses
- // small.
- if (stackAllocation) allocateStatic(stackAllocation, 16, ".stack");
-
- // The minimum initial memory size is the amount of static variables we have
- // allocated. Round it up to a page, and update the page-increment versions
- // of initial and max
- size_t initialMem = roundUpToPageSize(nextStatic);
- if (userInitialMemory) {
- if (initialMem > userInitialMemory) {
- Fatal() << "Specified initial memory size " << userInitialMemory <<
- " is smaller than required size " << initialMem;
- }
- wasm.memory.initial = userInitialMemory / Memory::kPageSize;
- } else {
- wasm.memory.initial = initialMem / Memory::kPageSize;
- }
-
- if (userMaxMemory) wasm.memory.max = userMaxMemory / Memory::kPageSize;
- wasm.memory.exportName = MEMORY;
-
- // XXX For now, export all functions marked .globl.
- for (Name name : globls) exportFunction(name, false);
- for (Name name : initializerFunctions) exportFunction(name, true);
-
- auto ensureFunctionIndex = [this](Name name) {
- if (functionIndexes.count(name) == 0) {
- functionIndexes[name] = wasm.table.names.size();
- wasm.table.names.push_back(name);
- if (debug) {
- std::cerr << "function index: " << name << ": "
- << functionIndexes[name] << '\n';
- }
- }
- };
- for (auto& relocation : relocations) {
- Name name = relocation->value;
- if (debug) std::cerr << "fix relocation " << name << '\n';
- const auto& symbolAddress = staticAddresses.find(name);
- if (symbolAddress != staticAddresses.end()) {
- *(relocation->data) = symbolAddress->second + relocation->offset;
- if (debug) std::cerr << " ==> " << *(relocation->data) << '\n';
- } else {
- // must be a function address
- auto aliased = aliasedFunctions.find(name);
- if (aliased != aliasedFunctions.end()) name = aliased->second;
- if (!wasm.checkFunction(name)) {
- std::cerr << "Unknown symbol: " << name << '\n';
- if (!ignoreUnknownSymbols) abort();
- *(relocation->data) = 0;
- } else {
- ensureFunctionIndex(name);
- *(relocation->data) = functionIndexes[name] + relocation->offset;
- }
- }
- }
- if (!!startFunction) {
- if (implementedFunctions.count(startFunction) == 0) {
- std::cerr << "Unknown start function: `" << startFunction << "`\n";
- abort();
- }
- const auto *target = wasm.getFunction(startFunction);
- Name start("_start");
- if (implementedFunctions.count(start) != 0) {
- std::cerr << "Start function already present: `" << start << "`\n";
- abort();
- }
- auto* func = wasm.allocator.alloc<Function>();
- func->name = start;
- wasm.addFunction(func);
- exportFunction(start, true);
- wasm.addStart(start);
- auto* block = wasm.allocator.alloc<Block>();
- func->body = block;
- {
- // Create the call, matching its parameters.
- // TODO allow calling with non-default values.
- auto* call = wasm.allocator.alloc<Call>();
- call->target = startFunction;
- size_t paramNum = 0;
- for (WasmType type : target->params) {
- Name name = Name::fromInt(paramNum++);
- Builder::addVar(func, name, type);
- auto* param = wasm.allocator.alloc<GetLocal>();
- param->index = func->getLocalIndex(name);
- param->type = type;
- call->operands.push_back(param);
- }
- block->list.push_back(call);
- block->finalize();
- }
- }
-
- // ensure an explicit function type for indirect call targets
- for (auto& name : wasm.table.names) {
- auto* func = wasm.getFunction(name);
- func->type = ensureFunctionType(getSig(func), &wasm, wasm.allocator)->name;
- }
- }
+ void layout();
// Support for emscripten integration: generates dyncall thunks, emits
// metadata for asmConsts, staticBump and initializer functions.
- void emscriptenGlue(std::ostream& o) {
- if (debug) {
- WasmPrinter::printModule(&wasm, std::cerr);
- }
-
- wasm.removeImport(EMSCRIPTEN_ASM_CONST); // we create _sig versions
-
- makeDynCallThunks();
-
- o << ";; METADATA: { ";
- // find asmConst calls, and emit their metadata
- struct AsmConstWalker : public PostWalker<AsmConstWalker, Visitor<AsmConstWalker>> {
- Linker* parent;
-
- std::map<std::string, std::set<std::string>> sigsForCode;
- std::map<std::string, size_t> ids;
- std::set<std::string> allSigs;
-
- void visitCallImport(CallImport* curr) {
- if (curr->target == EMSCRIPTEN_ASM_CONST) {
- auto arg = curr->operands[0]->cast<Const>();
- size_t segmentIndex = parent->addressSegments[arg->value.geti32()];
- std::string code = escape(parent->wasm.memory.segments[segmentIndex].data);
- int32_t id;
- if (ids.count(code) == 0) {
- id = ids.size();
- ids[code] = id;
- } else {
- id = ids[code];
- }
- std::string sig = getSig(curr);
- sigsForCode[code].insert(sig);
- std::string fixedTarget = EMSCRIPTEN_ASM_CONST.str + std::string("_") + sig;
- curr->target = cashew::IString(fixedTarget.c_str(), false);
- arg->value = Literal(id);
- // add import, if necessary
- if (allSigs.count(sig) == 0) {
- allSigs.insert(sig);
- auto import = parent->wasm.allocator.alloc<Import>();
- import->name = import->base = curr->target;
- import->module = ENV;
- import->type = ensureFunctionType(getSig(curr), &parent->wasm, parent->wasm.allocator);
- parent->wasm.addImport(import);
- }
- }
- }
-
- std::string escape(const char *input) {
- std::string code = input;
- // replace newlines quotes with escaped newlines
- size_t curr = 0;
- while ((curr = code.find("\\n", curr)) != std::string::npos) {
- code = code.replace(curr, 2, "\\\\n");
- curr += 3; // skip this one
- }
- // replace double quotes with escaped single quotes
- curr = 0;
- while ((curr = code.find('"', curr)) != std::string::npos) {
- if (curr == 0 || code[curr-1] != '\\') {
- code = code.replace(curr, 1, "\\" "\"");
- curr += 2; // skip this one
- } else { // already escaped, escape the slash as well
- code = code.replace(curr, 1, "\\" "\\" "\"");
- curr += 3; // skip this one
- }
- }
- return code;
- }
- };
- AsmConstWalker walker;
- walker.parent = this;
- walker.startWalk(&wasm);
- // print
- o << "\"asmConsts\": {";
- bool first = true;
- for (auto& pair : walker.sigsForCode) {
- auto& code = pair.first;
- auto& sigs = pair.second;
- if (first) first = false;
- else o << ",";
- o << '"' << walker.ids[code] << "\": [\"" << code << "\", ";
- printSet(o, sigs);
- o << "]";
- }
- o << "}";
- o << ",";
- o << "\"staticBump\": " << (nextStatic - globalBase) << ", ";
-
- o << "\"initializers\": [";
- first = true;
- for (const auto& func : initializerFunctions) {
- if (first) first = false;
- else o << ", ";
- o << "\"" << func.c_str() << "\"";
- }
- o << "]";
-
- o << " }";
- }
+ void emscriptenGlue(std::ostream& o);
private:
- // Allocate space for a stack pointer and (if stackAllocation > 0) set up a
- // relocation for it to point to the top of the stack.
- void placeStackPointer(size_t stackAllocation) {
- // ensure this is the first allocation
- assert(nextStatic == globalBase || nextStatic == 1);
- const size_t pointerSize = 4;
- // Unconditionally allocate space for the stack pointer. Emscripten
- // allocates the stack itself, and initializes the stack pointer itself.
- size_t address = allocateStatic(pointerSize, pointerSize, "__stack_pointer");
- if (stackAllocation) {
- // If we are allocating the stack, set up a relocation to initialize the
- // stack pointer to point to one past-the-end of the stack allocation.
- auto* raw = new uint32_t;
- relocations.emplace_back(
- make_unique<Relocation>(raw, ".stack", stackAllocation));
- assert(wasm.memory.segments.size() == 0);
- addressSegments[address] = wasm.memory.segments.size();
- wasm.memory.segments.emplace_back(
- address, reinterpret_cast<char*>(raw), pointerSize);
- }
- }
-
template<class C>
void printSet(std::ostream& o, C& c) {
o << "[";
@@ -371,29 +150,7 @@ class Linker {
// Create thunks for use with emscripten Runtime.dynCall. Creates one for each
// signature in the indirect function table.
- void makeDynCallThunks() {
- std::unordered_set<std::string> sigs;
- wasm::Builder wasmBuilder(wasm);
- for (const auto& indirectFunc : wasm.table.names) {
- std::string sig(getSig(wasm.getFunction(indirectFunc)));
- auto* funcType = ensureFunctionType(sig, &wasm, wasm.allocator);
- if (!sigs.insert(sig).second) continue; // Sig is already in the set
- std::vector<NameType> params;
- params.emplace_back("fptr", i32); // function pointer param
- int p = 0;
- for (const auto& ty : funcType->params) params.emplace_back("$" + std::to_string(p++), ty);
- Function* f = wasmBuilder.makeFunction(std::string("dynCall_") + sig, std::move(params), funcType->result, {});
- Expression* fptr = wasmBuilder.makeGetLocal(0, i32);
- std::vector<Expression*> args;
- for (unsigned i = 0; i < funcType->params.size(); ++i) {
- args.push_back(wasmBuilder.makeGetLocal(i + 1, funcType->params[i]));
- }
- Expression* call = wasmBuilder.makeCallIndirect(funcType, fptr, std::move(args));
- f->body = funcType->result == none ? call : wasmBuilder.makeReturn(call);
- wasm.addFunction(f);
- exportFunction(f->name, true);
- }
- }
+ void makeDynCallThunks();
static size_t roundUpToPageSize(size_t size) {
return (size + Memory::kPageSize - 1) & Memory::kPageMask;
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