sunfish created this revision.
sunfish added a reviewer: sbc100.
Herald added subscribers: llvm-commits, aheejin, jfb.
WebAssembly, the architecture, is not designed to support unprototyped calling
conventions. For example, clang tends to assume that it can use varargs to
implement parts of the unprototyped function rules, which works on most other
architectures, however WebAssembly has no straightforward way of allowing
functions to be callable as both varargs and non-varargs. LLVM's backend does
find ways to make things work in some cases, however the support is incomplete.
To protect users from accidentally trying to compile such code and encountering
bugs, this patch enables -Werror=strict-prototypes by default for the
WebAssembly target.
Repository:
rL LLVM
https://reviews.llvm.org/D43540
Files:
lib/Driver/ToolChains/Clang.cpp
test/Driver/wasm-toolchain.c
Index: test/Driver/wasm-toolchain.c
===================================================================
--- test/Driver/wasm-toolchain.c
+++ test/Driver/wasm-toolchain.c
@@ -1,15 +1,21 @@
// A basic clang -cc1 command-line. WebAssembly is somewhat special in
-// enabling -fvisibility=hidden by default.
+// enabling -fvisibility=hidden and -Werror-strict-prototypes by default.
// RUN: %clang %s -### -no-canonical-prefixes -target wasm32-unknown-unknown
2>&1 | FileCheck -check-prefix=CC1 %s
-// CC1: clang{{.*}} "-cc1" "-triple" "wasm32-unknown-unknown" {{.*}}
"-fvisibility" "hidden" {{.*}}
+// CC1: clang{{.*}} "-cc1" "-triple" "wasm32-unknown-unknown" {{.*}}
"-Werror=strict-prototypes" "-fvisibility" "hidden" {{.*}}
// Ditto, but ensure that a user -fvisibility=default disables the default
// -fvisibility=hidden.
// RUN: %clang %s -### -target wasm32-unknown-unknown -fvisibility=default
2>&1 | FileCheck -check-prefix=FVISIBILITY_DEFAULT %s
// FVISIBILITY_DEFAULT-NOT: hidden
+// Ensure that a user -Wno-strict-prototypes disabled the default
+// -Werror=strict-prototypes.
+
+// RUN: %clang %s -### -target wasm32-unknown-unknown -Wno-strict-prototypes
2>&1 | FileCheck -check-prefix=WNO_STRICT_PROTOTYPES %s
+// WNO_STRICT_PROTOTYPES: "-Werror=strict-prototypes" {{.*}}
"-Wno-strict-prototypes"
+
// A basic C link command-line.
// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown
--sysroot=/foo %s 2>&1 | FileCheck -check-prefix=LINK %s
Index: lib/Driver/ToolChains/Clang.cpp
===================================================================
--- lib/Driver/ToolChains/Clang.cpp
+++ lib/Driver/ToolChains/Clang.cpp
@@ -1820,6 +1820,9 @@
void Clang::AddWebAssemblyTargetArgs(const ArgList &Args,
ArgStringList &CmdArgs) const {
+ // WebAssembly doesn't fully support code without prototypes.
+ CmdArgs.push_back("-Werror=strict-prototypes");
+
// Default to "hidden" visibility.
if (!Args.hasArg(options::OPT_fvisibility_EQ,
options::OPT_fvisibility_ms_compat)) {
Index: test/Driver/wasm-toolchain.c
===================================================================
--- test/Driver/wasm-toolchain.c
+++ test/Driver/wasm-toolchain.c
@@ -1,15 +1,21 @@
// A basic clang -cc1 command-line. WebAssembly is somewhat special in
-// enabling -fvisibility=hidden by default.
+// enabling -fvisibility=hidden and -Werror-strict-prototypes by default.
// RUN: %clang %s -### -no-canonical-prefixes -target wasm32-unknown-unknown 2>&1 | FileCheck -check-prefix=CC1 %s
-// CC1: clang{{.*}} "-cc1" "-triple" "wasm32-unknown-unknown" {{.*}} "-fvisibility" "hidden" {{.*}}
+// CC1: clang{{.*}} "-cc1" "-triple" "wasm32-unknown-unknown" {{.*}} "-Werror=strict-prototypes" "-fvisibility" "hidden" {{.*}}
// Ditto, but ensure that a user -fvisibility=default disables the default
// -fvisibility=hidden.
// RUN: %clang %s -### -target wasm32-unknown-unknown -fvisibility=default 2>&1 | FileCheck -check-prefix=FVISIBILITY_DEFAULT %s
// FVISIBILITY_DEFAULT-NOT: hidden
+// Ensure that a user -Wno-strict-prototypes disabled the default
+// -Werror=strict-prototypes.
+
+// RUN: %clang %s -### -target wasm32-unknown-unknown -Wno-strict-prototypes 2>&1 | FileCheck -check-prefix=WNO_STRICT_PROTOTYPES %s
+// WNO_STRICT_PROTOTYPES: "-Werror=strict-prototypes" {{.*}} "-Wno-strict-prototypes"
+
// A basic C link command-line.
// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s 2>&1 | FileCheck -check-prefix=LINK %s
Index: lib/Driver/ToolChains/Clang.cpp
===================================================================
--- lib/Driver/ToolChains/Clang.cpp
+++ lib/Driver/ToolChains/Clang.cpp
@@ -1820,6 +1820,9 @@
void Clang::AddWebAssemblyTargetArgs(const ArgList &Args,
ArgStringList &CmdArgs) const {
+ // WebAssembly doesn't fully support code without prototypes.
+ CmdArgs.push_back("-Werror=strict-prototypes");
+
// Default to "hidden" visibility.
if (!Args.hasArg(options::OPT_fvisibility_EQ,
options::OPT_fvisibility_ms_compat)) {
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