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Remove Roblox-specific mutable globals (#185) 

Instead the code that calls the compiler needs to use Compiler::mutableGlobals to disable GETIMPORT optimization.
This commit is contained in:
LoganDark 2021-11-09 07:06:25 -08:00 committed by GitHub
parent 773fb5bd6f
commit 9523670e63
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3 changed files with 141 additions and 8 deletions
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4
Compiler/include/Luau/Compiler.h
View File

@ -36,6 +36,10 @@ struct CompileOptions
// global builtin to construct vectors; disabled by default
const char* vectorLib = nullptr;
const char* vectorCtor = nullptr;
// array of globals that are mutable; disables the import optimization for fields accessed through them
// use NULL to end the array
const char** mutableGlobals = nullptr;
};
class CompileError : public std::exception

30
Compiler/src/Compiler.cpp
View File

@ -13,6 +13,7 @@
LUAU_FASTFLAGVARIABLE(LuauPreloadClosures, false)
LUAU_FASTFLAGVARIABLE(LuauPreloadClosuresFenv, false)
LUAU_FASTFLAGVARIABLE(LuauPreloadClosuresUpval, false)
LUAU_FASTFLAGVARIABLE(LuauGenericSpecialGlobals, false)
LUAU_FASTFLAG(LuauIfElseExpressionBaseSupport)
namespace Luau
@ -1277,7 +1278,7 @@ struct Compiler
{
const Global* global = globals.find(expr->name);
return options.optimizationLevel >= 1 && (!global || (!global->written && !global->special));
return options.optimizationLevel >= 1 && (!global || (!global->written && !global->writable));
}
void compileExprIndexName(AstExprIndexName* expr, uint8_t target)
@ -3447,7 +3448,7 @@ struct Compiler
struct Global
{
bool special = false;
bool writable = false;
bool written = false;
};
@ -3505,7 +3506,7 @@ struct Compiler
{
Global* g = globals.find(object->name);
return !g || (!g->special && !g->written) ? Builtin{object->name, expr->index} : Builtin();
return !g || (!g->writable && !g->written) ? Builtin{object->name, expr->index} : Builtin();
}
else
{
@ -3703,13 +3704,26 @@ void compileOrThrow(BytecodeBuilder& bytecode, AstStatBlock* root, const AstName
Compiler compiler(bytecode, options);
// since access to some global objects may result in values that change over time, we block table imports
for (const char* global : kSpecialGlobals)
// since access to some global objects may result in values that change over time, we block imports from non-readonly tables
if (FFlag::LuauGenericSpecialGlobals)
{
AstName name = names.get(global);
if (AstName name = names.get("_G"); name.value)
compiler.globals[name].writable = true;
if (name.value)
compiler.globals[name].special = true;
if (options.mutableGlobals)
for (const char** ptr = options.mutableGlobals; *ptr != NULL; ++ptr)
{
if (AstName name = names.get(*ptr); name.value)
compiler.globals[name].writable = true;
}
}
else
{
for (const char* global : kSpecialGlobals)
{
if (AstName name = names.get(global); name.value)
compiler.globals[name].writable = true;
}
}
// this visitor traverses the AST to analyze mutability of locals/globals, filling Local::written and Global::written

115
tests/Compiler.test.cpp
View File

@ -13,6 +13,7 @@
LUAU_FASTFLAG(LuauPreloadClosures)
LUAU_FASTFLAG(LuauPreloadClosuresFenv)
LUAU_FASTFLAG(LuauPreloadClosuresUpval)
LUAU_FASTFLAG(LuauGenericSpecialGlobals)
using namespace Luau;
@ -3670,4 +3671,118 @@ RETURN R0 0
)");
}
TEST_CASE("LuauGenericSpecialGlobals")
{
const char* source = R"(
print()
Game.print()
Workspace.print()
_G.print()
game.print()
plugin.print()
script.print()
shared.print()
workspace.print()
)";
{
ScopedFastFlag genericSpecialGlobals{"LuauGenericSpecialGlobals", false};
// Check Roblox globals are here
CHECK_EQ("\n" + compileFunction0(source), R"(
GETIMPORT R0 1
CALL R0 0 0
GETIMPORT R1 3
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R1 5
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R1 7
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R1 9
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R1 11
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R1 13
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R1 15
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R1 17
GETTABLEKS R0 R1 K0
CALL R0 0 0
RETURN R0 0
)");
}
ScopedFastFlag genericSpecialGlobals{"LuauGenericSpecialGlobals", true};
// Check Roblox globals are no longer here
CHECK_EQ("\n" + compileFunction0(source), R"(
GETIMPORT R0 1
CALL R0 0 0
GETIMPORT R0 3
CALL R0 0 0
GETIMPORT R0 5
CALL R0 0 0
GETIMPORT R1 7
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R0 9
CALL R0 0 0
GETIMPORT R0 11
CALL R0 0 0
GETIMPORT R0 13
CALL R0 0 0
GETIMPORT R0 15
CALL R0 0 0
GETIMPORT R0 17
CALL R0 0 0
RETURN R0 0
)");
// Check we can add them back
Luau::BytecodeBuilder bcb;
bcb.setDumpFlags(Luau::BytecodeBuilder::Dump_Code);
Luau::CompileOptions options;
const char* mutableGlobals[] = {"Game", "Workspace", "game", "plugin", "script", "shared", "workspace", NULL};
options.mutableGlobals = &mutableGlobals[0];
Luau::compileOrThrow(bcb, source, options);
CHECK_EQ("\n" + bcb.dumpFunction(0), R"(
GETIMPORT R0 1
CALL R0 0 0
GETIMPORT R1 3
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R1 5
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R1 7
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R1 9
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R1 11
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R1 13
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R1 15
GETTABLEKS R0 R1 K0
CALL R0 0 0
GETIMPORT R1 17
GETTABLEKS R0 R1 K0
CALL R0 0 0
RETURN R0 0
)");
}
TEST_SUITE_END();