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Bug 1444673 - Baldr: refactor AllocateCodeBytes() (r=lth)

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--HG--
extra : rebase_source : 67249aa7eb18bc2c3c8263d4057687cf04285c7c
This commit is contained in:
Luke Wagner 2018-03-23 13:44:05 -05:00
parent efd709bd4f
commit 89d5682099
1 changed files with 15 additions and 22 deletions
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37
js/src/wasm/WasmCode.cpp
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@ -58,18 +58,20 @@ CodeSegment::~CodeSegment()
static uint32_t
RoundupCodeLength(uint32_t codeLength)
{
// codeLength is a multiple of the system's page size, but not necessarily
// a multiple of ExecutableCodePageSize.
MOZ_ASSERT(codeLength % gc::SystemPageSize() == 0);
// AllocateExecutableMemory() requires a multiple of ExecutableCodePageSize.
return JS_ROUNDUP(codeLength, ExecutableCodePageSize);
}
/* static */ UniqueCodeBytes
CodeSegment::AllocateCodeBytes(uint32_t codeLength)
{
codeLength = RoundupCodeLength(codeLength);
if (codeLength > MaxCodeBytesPerProcess)
return nullptr;
void* p = AllocateExecutableMemory(codeLength, ProtectionSetting::Writable);
static_assert(MaxCodeBytesPerProcess <= INT32_MAX, "rounding won't overflow");
uint32_t roundedCodeLength = RoundupCodeLength(codeLength);
void* p = AllocateExecutableMemory(roundedCodeLength, ProtectionSetting::Writable);
// If the allocation failed and the embedding gives us a last-ditch attempt
// to purge all memory (which, in gecko, does a purging GC/CC/GC), do that
@ -77,17 +79,20 @@ CodeSegment::AllocateCodeBytes(uint32_t codeLength)
if (!p) {
if (OnLargeAllocationFailure) {
OnLargeAllocationFailure();
p = AllocateExecutableMemory(codeLength, ProtectionSetting::Writable);
p = AllocateExecutableMemory(roundedCodeLength, ProtectionSetting::Writable);
}
}
if (!p)
return nullptr;
// Zero the padding.
memset(((uint8_t*)p) + codeLength, 0, roundedCodeLength - codeLength);
// We account for the bytes allocated in WasmModuleObject::create, where we
// have the necessary JSContext.
return UniqueCodeBytes((uint8_t*)p, FreeCode(codeLength));
return UniqueCodeBytes((uint8_t*)p, FreeCode(roundedCodeLength));
}
const Code&
@ -262,11 +267,7 @@ ModuleSegment::create(Tier tier,
const Metadata& metadata,
const CodeRangeVector& codeRanges)
{
// Round up the code size to page size since this is eventually required by
// the executable-code allocator and for setting memory protection.
uint32_t bytesNeeded = masm.bytesNeeded();
uint32_t padding = ComputeByteAlignment(bytesNeeded, gc::SystemPageSize());
uint32_t codeLength = bytesNeeded + padding;
uint32_t codeLength = masm.bytesNeeded();
UniqueCodeBytes codeBytes = AllocateCodeBytes(codeLength);
if (!codeBytes)
@ -275,9 +276,6 @@ ModuleSegment::create(Tier tier,
// We'll flush the icache after static linking, in initialize().
masm.executableCopy(codeBytes.get(), /* flushICache = */ false);
// Zero the padding.
memset(codeBytes.get() + bytesNeeded, 0, padding);
return create(tier, Move(codeBytes), codeLength, bytecode, linkData, metadata, codeRanges);
}
@ -289,17 +287,13 @@ ModuleSegment::create(Tier tier,
const Metadata& metadata,
const CodeRangeVector& codeRanges)
{
// The unlinked bytes are a snapshot of the MacroAssembler's contents so
// round up just like in the MacroAssembler overload above.
uint32_t padding = ComputeByteAlignment(unlinkedBytes.length(), gc::SystemPageSize());
uint32_t codeLength = unlinkedBytes.length() + padding;
uint32_t codeLength = unlinkedBytes.length();
UniqueCodeBytes codeBytes = AllocateCodeBytes(codeLength);
if (!codeBytes)
return nullptr;
memcpy(codeBytes.get(), unlinkedBytes.begin(), unlinkedBytes.length());
memset(codeBytes.get() + unlinkedBytes.length(), 0, padding);
memcpy(codeBytes.get(), unlinkedBytes.begin(), codeLength);
return create(tier, Move(codeBytes), codeLength, bytecode, linkData, metadata, codeRanges);
}
@ -395,7 +389,6 @@ ModuleSegment::deserialize(const uint8_t* cursor, const ShareableBytes& bytecode
if (!cursor)
return nullptr;
MOZ_ASSERT(length % gc::SystemPageSize() == 0);
UniqueCodeBytes bytes = AllocateCodeBytes(length);
if (!bytes)
return nullptr;