[lld] wasm-ld: Add allow-multiple-definition flag (PR #97699)
via llvm-commits
llvm-commits at lists.llvm.org
Mon Jul 8 12:44:25 PDT 2024
https://github.com/mzukovec updated https://github.com/llvm/llvm-project/pull/97699
>From 0c5cd703f979949c303ab432774063c6b1761a79 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20=C5=BDukovec?= <martin.zukovec at xlab.si>
Date: Mon, 8 Jul 2024 20:44:34 +0200
Subject: [PATCH] Add allow-multiple-definition and noinhibit-exec flags to
wasm-ld to enable duplicated definitions.
---
.../wasm/Inputs/allow-multiple-definition.s | 6 +++
lld/test/wasm/allow-multiple-definition.s | 38 +++++++++++++++++++
lld/wasm/Config.h | 5 +++
lld/wasm/Driver.cpp | 24 +++++++++++-
lld/wasm/Options.td | 7 ++++
lld/wasm/SymbolTable.cpp | 9 +++--
6 files changed, 85 insertions(+), 4 deletions(-)
create mode 100644 lld/test/wasm/Inputs/allow-multiple-definition.s
create mode 100644 lld/test/wasm/allow-multiple-definition.s
diff --git a/lld/test/wasm/Inputs/allow-multiple-definition.s b/lld/test/wasm/Inputs/allow-multiple-definition.s
new file mode 100644
index 00000000000000..7a5577cb12791e
--- /dev/null
+++ b/lld/test/wasm/Inputs/allow-multiple-definition.s
@@ -0,0 +1,6 @@
+ .hidden foo
+ .globl foo
+foo:
+ .functype foo () -> (i32)
+ i32.const 1
+ end_function
diff --git a/lld/test/wasm/allow-multiple-definition.s b/lld/test/wasm/allow-multiple-definition.s
new file mode 100644
index 00000000000000..93fccd3c46f907
--- /dev/null
+++ b/lld/test/wasm/allow-multiple-definition.s
@@ -0,0 +1,38 @@
+# RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown %s -o %t1
+# RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown %p/Inputs/allow-multiple-definition.s -o %t2
+# RUN: not wasm-ld %t1 %t2 -o /dev/null
+# RUN: not wasm-ld --allow-multiple-definition --no-allow-multiple-definition %t1 %t2 -o /dev/null
+# RUN: wasm-ld --allow-multiple-definition --fatal-warnings %t1 %t2 -o %t3
+# RUN: wasm-ld --allow-multiple-definition --fatal-warnings %t2 %t1 -o %t4
+# RUN: llvm-objdump --no-print-imm-hex -d %t3 | FileCheck %s
+# RUN: llvm-objdump --no-print-imm-hex -d %t4 | FileCheck --check-prefix=REVERT %s
+
+# RUN: wasm-ld --noinhibit-exec %t2 %t1 -o /dev/null 2>&1 | FileCheck %s --check-prefix=WARN
+# WARN: warning: duplicate symbol: foo
+
+# RUN: wasm-ld -z muldefs --fatal-warnings %t1 %t2 -o %t3
+# RUN: wasm-ld -z muldefs --fatal-warnings %t2 %t1 -o %t4
+# RUN: llvm-objdump --no-print-imm-hex -d %t3 | FileCheck %s
+# RUN: llvm-objdump --no-print-imm-hex -d %t4 | FileCheck --check-prefix=REVERT %s
+
+# CHECK: i32.const 0
+# REVERT: i32.const 1
+
+# inputs contain different constants for function foo return.
+# Tests below checks that order of files in command line
+# affects on what symbol will be used.
+# If flag allow-multiple-definition is enabled the first
+# meet symbol should be used.
+
+ .hidden foo
+ .globl foo
+foo:
+ .functype foo () -> (i32)
+ i32.const 0
+ end_function
+
+ .globl _start
+_start:
+ .functype _start () -> (i32)
+ call foo
+ end_function
diff --git a/lld/wasm/Config.h b/lld/wasm/Config.h
index d0ffa83d111e07..98fd33373779a7 100644
--- a/lld/wasm/Config.h
+++ b/lld/wasm/Config.h
@@ -12,6 +12,7 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSet.h"
+#include "llvm/ADT/Twine.h"
#include "llvm/BinaryFormat/Wasm.h"
#include "llvm/Support/CachePruning.h"
#include <optional>
@@ -43,6 +44,7 @@ enum class BuildIdKind { None, Fast, Sha1, Hexstring, Uuid };
// and such fields have the same name as the corresponding options.
// Most fields are initialized by the driver.
struct Configuration {
+ bool allowMultipleDefinition;
bool bsymbolic;
bool checkFeatures;
bool compressRelocations;
@@ -64,6 +66,7 @@ struct Configuration {
bool importUndefined;
std::optional<bool> is64;
bool mergeDataSegments;
+ bool noinhibitExec;
bool pie;
bool printGcSections;
bool relocatable;
@@ -147,6 +150,8 @@ struct Ctx {
extern Ctx ctx;
+void errorOrWarn(const llvm::Twine &msg);
+
} // namespace lld::wasm
#endif
diff --git a/lld/wasm/Driver.cpp b/lld/wasm/Driver.cpp
index d099689911fc6b..025b7ffc2ba953 100644
--- a/lld/wasm/Driver.cpp
+++ b/lld/wasm/Driver.cpp
@@ -47,6 +47,13 @@ namespace lld::wasm {
Configuration *config;
Ctx ctx;
+void errorOrWarn(const llvm::Twine &msg) {
+ if (config->noinhibitExec)
+ warn(msg);
+ else
+ error(msg);
+}
+
void Ctx::reset() {
objectFiles.clear();
stubFiles.clear();
@@ -99,6 +106,16 @@ class LinkerDriver {
std::vector<InputFile *> files;
};
+
+static bool hasZOption(opt::InputArgList &args, StringRef key) {
+ bool ret = false;
+ for (const auto *arg : args.filtered(OPT_z))
+ if (key == arg->getValue()) {
+ ret = true;
+ arg->claim();
+ }
+ return ret;
+}
} // anonymous namespace
bool link(ArrayRef<const char *> args, llvm::raw_ostream &stdoutOS,
@@ -467,6 +484,10 @@ getBuildId(opt::InputArgList &args) {
// Initializes Config members by the command line options.
static void readConfigs(opt::InputArgList &args) {
+ config->allowMultipleDefinition =
+ hasZOption(args, "muldefs") ||
+ args.hasFlag(OPT_allow_multiple_definition,
+ OPT_no_allow_multiple_definition, false);
config->bsymbolic = args.hasArg(OPT_Bsymbolic);
config->checkFeatures =
args.hasFlag(OPT_check_features, OPT_no_check_features, true);
@@ -479,6 +500,7 @@ static void readConfigs(opt::InputArgList &args) {
config->exportAll = args.hasArg(OPT_export_all);
config->exportTable = args.hasArg(OPT_export_table);
config->growableTable = args.hasArg(OPT_growable_table);
+ config->noinhibitExec = args.hasArg(OPT_noinhibit_exec);
if (args.hasArg(OPT_import_memory_with_name)) {
config->memoryImport =
@@ -1161,7 +1183,7 @@ static void splitSections() {
static bool isKnownZFlag(StringRef s) {
// For now, we only support a very limited set of -z flags
- return s.starts_with("stack-size=");
+ return s.starts_with("stack-size=") || s.starts_with("muldefs");
}
// Report a warning for an unknown -z option.
diff --git a/lld/wasm/Options.td b/lld/wasm/Options.td
index 7e954822ef6425..ed9690195613c2 100644
--- a/lld/wasm/Options.td
+++ b/lld/wasm/Options.td
@@ -42,6 +42,10 @@ def Bdynamic: F<"Bdynamic">, HelpText<"Link against shared libraries">;
def Bstatic: F<"Bstatic">, HelpText<"Do not link against shared libraries (default)">;
+defm allow_multiple_definition: B<"allow-multiple-definition",
+ "Allow multiple definitions",
+ "Do not allow multiple definitions (default)">;
+
def build_id: F<"build-id">, HelpText<"Alias for --build-id=fast">;
def build_id_eq: J<"build-id=">, HelpText<"Generate build ID note">,
@@ -106,6 +110,9 @@ defm Map: Eq<"Map", "Print a link map to the specified file">;
def no_fatal_warnings: F<"no-fatal-warnings">;
+def noinhibit_exec: F<"noinhibit-exec">,
+ HelpText<"Retain the executable output file whenever it is still usable">;
+
def o: JoinedOrSeparate<["-"], "o">, MetaVarName<"<path>">,
HelpText<"Path to file to write output">;
diff --git a/lld/wasm/SymbolTable.cpp b/lld/wasm/SymbolTable.cpp
index 081f811cd139dd..2d52f100e68e86 100644
--- a/lld/wasm/SymbolTable.cpp
+++ b/lld/wasm/SymbolTable.cpp
@@ -310,9 +310,12 @@ static bool shouldReplace(const Symbol *existing, InputFile *newFile,
}
// Neither symbol is week. They conflict.
- error("duplicate symbol: " + toString(*existing) + "\n>>> defined in " +
- toString(existing->getFile()) + "\n>>> defined in " +
- toString(newFile));
+ if (config->allowMultipleDefinition) {
+ return false;
+ }
+ errorOrWarn("duplicate symbol: " + toString(*existing) + "\n>>> defined in " +
+ toString(existing->getFile()) + "\n>>> defined in " +
+ toString(newFile));
return true;
}
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