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[WebAssembly] Allow undefined symbols when building shared libraries 

Differential Revision: https://reviews.llvm.org/D55043

llvm-svn: 347909
This commit is contained in:
Sam Clegg 2018-11-29 20:07:13 +00:00
parent 80fabab677
commit 0f90191faa
2 changed files with 26 additions and 17 deletions
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27
lld/test/wasm/shared.ll
View File

@ -4,27 +4,34 @@
target triple = "wasm32-unknown-unknown"
@used_data = hidden global i32 2, align 4
@data = hidden global i32 2, align 4
@indirect_func = local_unnamed_addr global void ()* @foo, align 4
@indirect_func_external = local_unnamed_addr global void ()* @func_external, align 4
define default void @foo() {
entry:
; To ensure we use __stack_pointer
%ptr = alloca i32
%0 = load i32, i32* @used_data, align 4
%1 = load void ()*, void ()** @indirect_func, align 4
call void %1()
%0 = load i32, i32* @data, align 4
%1 = load i32, i32* @data_external, align 4
%2 = load void ()*, void ()** @indirect_func, align 4
call void %2()
ret void
}
declare void @func_external()
@data_external = external global i32
; check for dylink section at start
; CHECK: Sections:
; CHECK-NEXT: - Type: CUSTOM
; CHECK-NEXT: Name: dylink
; CHECK-NEXT: MemorySize: 4
; CHECK-NEXT: MemorySize: 8
; CHECK-NEXT: MemoryAlignment: 2
; CHECK-NEXT: TableSize: 1
; CHECK-NEXT: TableSize: 2
; CHECK-NEXT: TableAlignment: 0
; check for import of __table_base and __memory_base globals
@ -38,8 +45,8 @@ entry:
; CHECK-NEXT: ElemType: ANYFUNC
; CHECK-NEXT: Limits:
; CHECK-NEXT: Flags: [ HAS_MAX ]
; CHECK-NEXT: Initial: 0x00000001
; CHECK-NEXT: Maximum: 0x00000001
; CHECK-NEXT: Initial: 0x00000002
; CHECK-NEXT: Maximum: 0x00000002
; CHECK-NEXT: - Module: env
; CHECK-NEXT: Field: __stack_pointer
; CHECK-NEXT: Kind: GLOBAL
@ -63,7 +70,7 @@ entry:
; CHECK-NEXT: - Offset:
; CHECK-NEXT: Opcode: GET_GLOBAL
; CHECK-NEXT: Index: 2
; CHECK-NEXT: Functions: [ 1 ]
; CHECK-NEXT: Functions: [ 2, 0 ]
; check the data segment initialized with __memory_base global as offset
@ -74,4 +81,4 @@ entry:
; CHECK-NEXT: Offset:
; CHECK-NEXT: Opcode: GET_GLOBAL
; CHECK-NEXT: Index: 1
; CHECK-NEXT: Content: '00000000'
; CHECK-NEXT: Content: '0000000001000000'

16
lld/wasm/Driver.cpp
View File

@ -313,8 +313,7 @@ static void handleWeakUndefines() {
// be GC'd if not used as the target of any "call" instructions.
std::string SymName = toString(*Sym);
StringRef DebugName = Saver.save("undefined function " + SymName);
SyntheticFunction *Func =
make<SyntheticFunction>(Sig, Sym->getName(), DebugName);
auto *Func = make<SyntheticFunction>(Sig, Sym->getName(), DebugName);
Func->setBody(UnreachableFn);
// Ensure it compares equal to the null pointer, and so that table relocs
// don't pull in the stub body (only call-operand relocs should do that).
@ -448,9 +447,10 @@ static void createSyntheticSymbols() {
static llvm::wasm::WasmGlobalType MutableGlobalTypeI32 = {WASM_TYPE_I32,
true};
WasmSym::CallCtors = Symtab->addSyntheticFunction(
"__wasm_call_ctors", WASM_SYMBOL_VISIBILITY_HIDDEN,
make<SyntheticFunction>(NullSignature, "__wasm_call_ctors"));
if (!Config->Relocatable)
WasmSym::CallCtors = Symtab->addSyntheticFunction(
"__wasm_call_ctors", WASM_SYMBOL_VISIBILITY_HIDDEN,
make<SyntheticFunction>(NullSignature, "__wasm_call_ctors"));
// The __stack_pointer is imported in the shared library case, and exported
// in the non-shared (executable) case.
@ -463,7 +463,7 @@ static void createSyntheticSymbols() {
Global.InitExpr.Value.Int32 = 0;
Global.InitExpr.Opcode = WASM_OPCODE_I32_CONST;
Global.SymbolName = "__stack_pointer";
InputGlobal *StackPointer = make<InputGlobal>(Global, nullptr);
auto *StackPointer = make<InputGlobal>(Global, nullptr);
StackPointer->Live = true;
// For non-PIC code
// TODO(sbc): Remove WASM_SYMBOL_VISIBILITY_HIDDEN when the mutable global
@ -543,8 +543,10 @@ void LinkerDriver::link(ArrayRef<const char *> ArgsArr) {
Config->ImportTable = true;
}
if (Config->Shared)
if (Config->Shared) {
Config->ExportDynamic = true;
Config->AllowUndefined = true;
}
if (!Config->Relocatable)
createSyntheticSymbols();