Commit bb66d8f8 authored by YAMAMOTO Takashi's avatar YAMAMOTO Takashi Committed by Tobias Hieta
Browse files

[clang][WebAssembly] Link crt1 even in case of -shared 

This allows -mexec-model=reactor -shared produces a library module
with _initialize entrypoint, which is preferrable over __wasm_call_ctors.

This partially reverts https://reviews.llvm.org/D153293

Discussion: https://github.com/dicej/component-linking-demo/issues/3

Reviewed By: sbc100

Differential Revision: https://reviews.llvm.org/D156205

(cherry picked from commit 989ce069)
parent 98bfdac5

clang/lib/Driver/ToolChains/WebAssembly.cpp

+25 −13
Original line number Diff line number Diff line
@@ -77,31 +77,43 @@ void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA, 
  Args.AddAllArgs(CmdArgs, options::OPT_u);

  ToolChain.AddFilePathLibArgs(Args, CmdArgs);



  const char *Crt1 = "crt1.o";

  bool IsCommand = true;

  const char *Crt1;

  const char *Entry = nullptr;



  // When -shared is specified, use the reactor exec model unless

  // specified otherwise.

  if (Args.hasArg(options::OPT_shared))

    IsCommand = false;



  if (const Arg *A = Args.getLastArg(options::OPT_mexec_model_EQ)) {

    StringRef CM = A->getValue();

    if (CM == "command") {

      IsCommand = true;

    } else if (CM == "reactor") {

      IsCommand = false;

    } else {

      ToolChain.getDriver().Diag(diag::err_drv_invalid_argument_to_option)

          << CM << A->getOption().getName();

    }

  }



  if (IsCommand) {

    // If crt1-command.o exists, it supports new-style commands, so use it.

    // Otherwise, use the old crt1.o. This is a temporary transition measure.

    // Once WASI libc no longer needs to support LLVM versions which lack

    // support for new-style command, it can make crt1.o the same as

    // crt1-command.o. And once LLVM no longer needs to support WASI libc

    // versions before that, it can switch to using crt1-command.o.

    Crt1 = "crt1.o";

    if (ToolChain.GetFilePath("crt1-command.o") != "crt1-command.o")

      Crt1 = "crt1-command.o";



  if (const Arg *A = Args.getLastArg(options::OPT_mexec_model_EQ)) {

    StringRef CM = A->getValue();

    if (CM == "command") {

      // Use default values.

    } else if (CM == "reactor") {

  } else {

    Crt1 = "crt1-reactor.o";

    Entry = "_initialize";

    } else {

      ToolChain.getDriver().Diag(diag::err_drv_invalid_argument_to_option)

          << CM << A->getOption().getName();

  }

  }

  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles, options::OPT_shared))



  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles))

    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(Crt1)));

  if (Entry) {

    CmdArgs.push_back(Args.MakeArgString("--entry"));

clang/test/Driver/wasm-toolchain.c

+6 −6
Original line number Diff line number Diff line
@@ -33,19 +33,19 @@ 
// LINK_KNOWN: "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"

// LINK_KNOWN: wasm-ld{{.*}}" "-L/foo/lib/wasm32-wasi" "crt1.o" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"



// -shared should be passed through to `wasm-ld` and not include crt1.o with a known OS.

// -shared should be passed through to `wasm-ld` and include crt1-reactor.o with a known OS.



// RUN: %clang -### -shared --target=wasm32-wasi --sysroot=/foo %s 2>&1 \

// RUN: %clang -### -shared -mexec-model=reactor --target=wasm32-wasi --sysroot=/foo %s 2>&1 \

// RUN:   | FileCheck -check-prefix=LINK_KNOWN_SHARED %s

// LINK_KNOWN_SHARED: "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"

// LINK_KNOWN_SHARED: wasm-ld{{.*}}" "-L/foo/lib/wasm32-wasi" "-shared" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"

// LINK_KNOWN_SHARED: wasm-ld{{.*}}" "-L/foo/lib/wasm32-wasi" "crt1-reactor.o" "--entry" "_initialize" "-shared" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"



// -shared should be passed through to `wasm-ld` and not include crt1.o with an unknown OS.

// -shared should be passed through to `wasm-ld` and include crt1-reactor.o with an unknown OS.



// RUN: %clang -### -shared --target=wasm32-unknown-unknown --sysroot=/foo %s 2>&1 \

// RUN: %clang -### -shared -mexec-model=reactor --target=wasm32-unknown-unknown --sysroot=/foo %s 2>&1 \

// RUN:   | FileCheck -check-prefix=LINK_UNKNOWN_SHARED %s

// LINK_UNKNOWN_SHARED: "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"

// LINK_UNKNOWN_SHARED: wasm-ld{{.*}}" "-shared" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"

// LINK_UNKNOWN_SHARED: wasm-ld{{.*}}" "crt1-reactor.o" "--entry" "_initialize" "-shared" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"



// A basic C link command-line with optimization with known OS.