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Handle sbrk import by emscripten+upstream in SafeHeap #2332

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Merged
kripken merged 2 commits into from
Sep 6, 2019
Merged

Handle sbrk import by emscripten+upstream in SafeHeap #2332

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c3014df
fix
kripken Sep 6, 2019
57afcf8
style
kripken Sep 6, 2019
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30 changes: 20 additions & 10 deletions src/passes/SafeHeap.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -32,10 +32,11 @@

namespace wasm {

const Name DYNAMICTOP_PTR_IMPORT("DYNAMICTOP_PTR");
const Name GET_SBRK_PTR_IMPORT("emscripten_get_sbrk_ptr");
const Name SEGFAULT_IMPORT("segfault");
const Name ALIGNFAULT_IMPORT("alignfault");
static const Name DYNAMICTOP_PTR_IMPORT("DYNAMICTOP_PTR");
static const Name GET_SBRK_PTR_IMPORT("emscripten_get_sbrk_ptr");
static const Name SBRK("sbrk");
static const Name SEGFAULT_IMPORT("segfault");
static const Name ALIGNFAULT_IMPORT("alignfault");

static Name getLoadName(Load* curr) {
std::string ret = "SAFE_HEAP_LOAD_";
Expand Down Expand Up @@ -112,7 +113,7 @@ struct SafeHeap : public Pass {
addGlobals(module, module->features);
}

Name dynamicTopPtr, getSbrkPtr, segfault, alignfault;
Name dynamicTopPtr, getSbrkPtr, sbrk, segfault, alignfault;

void addImports(Module* module) {
ImportInfo info(*module);
Expand All @@ -124,6 +125,8 @@ struct SafeHeap : public Pass {
} else if (auto* existing =
info.getImportedFunction(ENV, GET_SBRK_PTR_IMPORT)) {
getSbrkPtr = existing->name;
} else if (auto* existing = info.getImportedFunction(ENV, SBRK)) {
sbrk = existing->name;
} else {
auto* import = new Function;
import->name = getSbrkPtr = GET_SBRK_PTR_IMPORT;
Expand Down Expand Up @@ -324,11 +327,18 @@ struct SafeHeap : public Pass {
makeBoundsCheck(Type type, Builder& builder, Index local, Index bytes) {
auto upperOp = options.lowMemoryUnused ? LtUInt32 : EqInt32;
auto upperBound = options.lowMemoryUnused ? PassOptions::LowMemoryBound : 0;
Expression* sbrkPtr;
if (dynamicTopPtr.is()) {
sbrkPtr = builder.makeGlobalGet(dynamicTopPtr, i32);
Expression* brkLocation;
if (sbrk.is()) {
brkLocation =
builder.makeCall(sbrk, {builder.makeConst(Literal(int32_t(0)))}, i32);
} else {
sbrkPtr = builder.makeCall(getSbrkPtr, {}, i32);
Expression* sbrkPtr;
if (dynamicTopPtr.is()) {
sbrkPtr = builder.makeGlobalGet(dynamicTopPtr, i32);
} else {
sbrkPtr = builder.makeCall(getSbrkPtr, {}, i32);
}
brkLocation = builder.makeLoad(4, false, 0, 4, sbrkPtr, i32);
}
return builder.makeIf(
builder.makeBinary(
Expand All @@ -341,7 +351,7 @@ struct SafeHeap : public Pass {
builder.makeBinary(AddInt32,
builder.makeLocalGet(local, i32),
builder.makeConst(Literal(int32_t(bytes)))),
builder.makeLoad(4, false, 0, 4, sbrkPtr, i32))),
brkLocation)),
builder.makeCall(segfault, {}, none));
}
};
Expand Down