diff --git a/lld/docs/WebAssembly.rst b/lld/docs/WebAssembly.rst
--- a/lld/docs/WebAssembly.rst
+++ b/lld/docs/WebAssembly.rst
@@ -72,7 +72,8 @@
.. option:: --allow-undefined
Allow undefined symbols in linked binary. This is the legacy
- flag which corresponds to ``--unresolved-symbols=import-functions``.
+ flag which corresponds to ``--unresolve-symbols=ignore`` +
+ ``--import-undefined``.
.. option:: --unresolved-symbols=<method>
@@ -91,16 +92,17 @@
this is trivial. For direct function calls, the linker will generate a
trapping stub function in place of the undefined function.
- import-functions:
-
- Generate WebAssembly imports for any undefined functions. Undefined data
- symbols are resolved to zero as in ``ignore-all``. This corresponds to
- the legacy ``--allow-undefined`` flag.
-
.. option:: --import-memory
Import memory from the environment.
+.. option:: --import-undefined
+
+ Generate WebAssembly imports for undefined symbols, where possible. For
+ example, for function symbols this is always possible, but in general this
+ is not possible for undefined data symbols. Undefined data symbols will
+ still be reported as normal (in accordance with ``--unresolved-symbols``).
+
.. option:: --initial-memory=<value>
Initial size of the linear memory. Default: static data size.
diff --git a/lld/test/wasm/unresolved-symbols.s b/lld/test/wasm/unresolved-symbols.s
--- a/lld/test/wasm/unresolved-symbols.s
+++ b/lld/test/wasm/unresolved-symbols.s
@@ -1,9 +1,9 @@
# RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown %s -o %t1.o
-## Check that %t1.o contains undefined symbol undef.
+## Check that %t1.o contains undefined symbol undef_func.
# RUN: not wasm-ld %t1.o -o /dev/null 2>&1 | \
# RUN: FileCheck -check-prefix=ERRUND %s
-# ERRUND: error: {{.*}}1.o: undefined symbol: undef
+# ERRUND: error: {{.*}}1.o: undefined symbol: undef_func
## report-all is the default one. Check that we get the same error
# RUN: not wasm-ld %t1.o -o /dev/null --unresolved-symbols=report-all 2>&1 | \
@@ -52,19 +52,25 @@
# IGNORE-NEXT: - Index: 3
# IGNORE-NEXT: Name: get_func_addr
-## import-functions should not produce errors and should resolve in
-# imports for the missing functions but not the missing data symbols.
-# `--allow-undefined` should behave exactly the same.
-# RUN: wasm-ld %t1.o -o %t3.wasm --unresolved-symbols=import-functions
+## --import-undefined should handle unresolved funtions symbols
+# by importing them but still report errors/warning for missing data symbols.
+# `--allow-undefined` should behave like `--import-undefined` +
+# `--unresolve-symbols=ignore`
+# RUN: wasm-ld %t1.o -o %t3.wasm --import-undefined --unresolved-symbols=ignore-all
# RUN: obj2yaml %t3.wasm | FileCheck -check-prefix=IMPORT %s
# IMPORT: - Type: IMPORT
# IMPORT-NEXT: Imports:
# IMPORT-NEXT: - Module: env
-# IMPORT-NEXT: Field: undef
+# IMPORT-NEXT: Field: undef_func
# IMPORT-NEXT: Kind: FUNCTION
# IMPORT-NEXT: SigIndex: 0
# IMPORT-NEXT: - Type: FUNCTION
+## Check that --import-undefined reports unresolved data symbols.
+# RUN: not wasm-ld %t1.o -o %t3.wasm --import-undefined --unresolved-symbols=report-all 2>&1 | FileCheck -check-prefix=IMPORTUNDEFINED %s
+# IMPORTUNDEFINED-NOT: error: {{.*}}1.o: undefined symbol: undef_func
+# IMPORTUNDEFINED: error: {{.*}}1.o: undefined symbol: undef_data
+
## Do not report undefines if linking relocatable.
# RUN: wasm-ld -r %t1.o -o %t4.wasm --unresolved-symbols=report-all
# RUN: llvm-readobj %t4.wasm > /dev/null 2>&1
@@ -72,7 +78,7 @@
.globl _start
_start:
.functype _start () -> ()
- call undef
+ call undef_func
call get_data_addr
call get_func_addr
end_function
@@ -87,8 +93,8 @@
.globl get_func_addr
get_func_addr:
.functype get_func_addr () -> (i32)
- i32.const undef
+ i32.const undef_func
return
end_function
-.functype undef () -> ()
+.functype undef_func () -> ()
diff --git a/lld/wasm/Config.h b/lld/wasm/Config.h
--- a/lld/wasm/Config.h
+++ b/lld/wasm/Config.h
@@ -18,10 +18,7 @@
namespace wasm {
// For --unresolved-symbols.
-// The `ImportFuncs` mode is an additional mode that corresponds to the
-// --allow-undefined flag which turns undefined functions in imports
-// as opposed ed to Ignore or Warn which turn them into unreachables.
-enum class UnresolvedPolicy { ReportError, Warn, Ignore, ImportFuncs };
+enum class UnresolvedPolicy { ReportError, Warn, Ignore };
// This struct contains the global configuration for the linker.
// Most fields are direct mapping from the command line options
@@ -43,6 +40,7 @@
bool importMemory;
bool sharedMemory;
bool importTable;
+ bool importUndefined;
llvm::Optional<bool> is64;
bool mergeDataSegments;
bool pie;
diff --git a/lld/wasm/Driver.cpp b/lld/wasm/Driver.cpp
--- a/lld/wasm/Driver.cpp
+++ b/lld/wasm/Driver.cpp
@@ -344,18 +344,11 @@
StringRef s = arg->getValue();
if (s == "ignore-all")
return UnresolvedPolicy::Ignore;
- if (s == "import-functions")
- return UnresolvedPolicy::ImportFuncs;
if (s == "report-all")
return errorOrWarn;
error("unknown --unresolved-symbols value: " + s);
}
- // Legacy --allow-undefined flag which is equivalent to
- // --unresolve-symbols=ignore-all
- if (args.hasArg(OPT_allow_undefined))
- return UnresolvedPolicy::ImportFuncs;
-
return errorOrWarn;
}
@@ -378,6 +371,7 @@
config->importMemory = args.hasArg(OPT_import_memory);
config->sharedMemory = args.hasArg(OPT_shared_memory);
config->importTable = args.hasArg(OPT_import_table);
+ config->importUndefined = args.hasArg(OPT_import_undefined);
config->ltoo = args::getInteger(args, OPT_lto_O, 2);
config->ltoPartitions = args::getInteger(args, OPT_lto_partitions, 1);
config->ltoNewPassManager =
@@ -453,6 +447,13 @@
config->features->push_back(std::string(s));
}
+ // Legacy --allow-undefined flag which is equivalent to
+ // --unresolve-symbols=ignore + --import-undefined
+ if (args.hasArg(OPT_allow_undefined)) {
+ config->importUndefined = true;
+ config->unresolvedSymbols = UnresolvedPolicy::Ignore;
+ }
+
if (args.hasArg(OPT_print_map))
config->mapFile = "-";
}
@@ -481,7 +482,8 @@
if (config->shared) {
config->importMemory = true;
- config->unresolvedSymbols = UnresolvedPolicy::ImportFuncs;
+ config->importUndefined = true;
+ config->unresolvedSymbols = UnresolvedPolicy::Ignore;
}
}
diff --git a/lld/wasm/Options.td b/lld/wasm/Options.td
--- a/lld/wasm/Options.td
+++ b/lld/wasm/Options.td
@@ -141,7 +141,11 @@
// The follow flags are unique to wasm
def allow_undefined: F<"allow-undefined">,
- HelpText<"Allow undefined symbols in linked binary">;
+ HelpText<"Allow undefined symbols in linked binary. This options is equivelant "
+ "to --import-undefined and --unresolved-symbols=ignore-all">;
+
+def import_undefined: F<"import-undefined">,
+ HelpText<"Turn undefined symbols into imports where possible">;
def allow_undefined_file: J<"allow-undefined-file=">,
HelpText<"Allow symbols listed in <file> to be undefined in linked binary">;
diff --git a/lld/wasm/Relocations.cpp b/lld/wasm/Relocations.cpp
--- a/lld/wasm/Relocations.cpp
+++ b/lld/wasm/Relocations.cpp
@@ -35,7 +35,7 @@
// Undefined functions and globals with explicit import name are allowed to be
// undefined at link time.
if (auto *f = dyn_cast<UndefinedFunction>(sym))
- if (f->importName)
+ if (f->importName || config->importUndefined)
return true;
if (auto *g = dyn_cast<UndefinedGlobal>(sym))
if (g->importName)
@@ -56,20 +56,20 @@
warn(toString(sym->getFile()) + ": undefined symbol: " + toString(*sym));
break;
case UnresolvedPolicy::Ignore:
- if (auto *f = dyn_cast<UndefinedFunction>(sym)) {
- if (!f->stubFunction) {
- LLVM_DEBUG(dbgs()
- << "ignoring undefined symbol: " + toString(*sym) + "\n");
- f->stubFunction = symtab->createUndefinedStub(*f->getSignature());
- f->stubFunction->markLive();
- // Mark the function itself as a stub which prevents it from being
- // assigned a table entry.
- f->isStub = true;
+ LLVM_DEBUG(dbgs() << "ignoring undefined symbol: " + toString(*sym) +
+ "\n");
+ if (!config->importUndefined) {
+ if (auto *f = dyn_cast<UndefinedFunction>(sym)) {
+ if (!f->stubFunction) {
+ f->stubFunction = symtab->createUndefinedStub(*f->getSignature());
+ f->stubFunction->markLive();
+ // Mark the function itself as a stub which prevents it from being
+ // assigned a table entry.
+ f->isStub = true;
+ }
}
}
break;
- case UnresolvedPolicy::ImportFuncs:
- break;
}
}
}
diff --git a/lld/wasm/Writer.cpp b/lld/wasm/Writer.cpp
--- a/lld/wasm/Writer.cpp
+++ b/lld/wasm/Writer.cpp
@@ -558,8 +558,7 @@
if (isa<DataSymbol>(sym))
return false;
- if ((config->isPic || config->relocatable) ||
- config->unresolvedSymbols == UnresolvedPolicy::ImportFuncs)
+ if (config->isPic || config->relocatable || config->importUndefined)
return true;
if (config->allowUndefinedSymbols.count(sym->getName()) != 0)
return true;