This revision was automatically updated to reflect the committed changes.
Closed by commit rG00072c08c750: [WebAssembly] Mangle the argc/argv `main` as
`__wasm_argc_argv`. (authored by sunfishcode).
Changed prior to commit:
https://reviews.llvm.org/D70700?vs=234942=247011#toc
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D70700/new/
https://reviews.llvm.org/D70700
Files:
clang/lib/AST/Mangle.cpp
clang/lib/CodeGen/CodeGenModule.cpp
clang/lib/CodeGen/CodeGenModule.h
clang/lib/Frontend/InitHeaderSearch.cpp
clang/test/CodeGen/wasm-call-main.c
clang/test/CodeGen/wasm-main.c
clang/test/CodeGen/wasm-main_argc_argv.c
Index: clang/test/CodeGen/wasm-main_argc_argv.c
===
--- /dev/null
+++ clang/test/CodeGen/wasm-main_argc_argv.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -triple wasm32 -o - -emit-llvm %s | FileCheck %s
+
+// Mangle the argc/argv form of main.
+
+int main(int argc, char **argv) {
+ return 0;
+}
+
+// CHECK-LABEL: define i32 @__main_argc_argv(i32 %argc, i8** %argv)
Index: clang/test/CodeGen/wasm-main.c
===
--- /dev/null
+++ clang/test/CodeGen/wasm-main.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -triple wasm32 -o - -emit-llvm %s | FileCheck %s
+
+// Don't mangle the no-arg form of main.
+
+int main(void) {
+ return 0;
+}
+
+// CHECK-LABEL: define i32 @main()
Index: clang/test/CodeGen/wasm-call-main.c
===
--- /dev/null
+++ clang/test/CodeGen/wasm-call-main.c
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -triple wasm32 -o - -emit-llvm %s | FileCheck %s
+
+// Mangle argc/argv main even when it's not defined in this TU.
+
+#include
+
+int main(int argc, char *argv[]);
+
+int foo(void) {
+return main(0, NULL);
+}
+
+// CHECK: call i32 @__main_argc_argv(
Index: clang/lib/Frontend/InitHeaderSearch.cpp
===
--- clang/lib/Frontend/InitHeaderSearch.cpp
+++ clang/lib/Frontend/InitHeaderSearch.cpp
@@ -433,8 +433,7 @@
break;
case llvm::Triple::UnknownOS:
-if (triple.getArch() == llvm::Triple::wasm32 ||
-triple.getArch() == llvm::Triple::wasm64)
+if (triple.isWasm())
return;
break;
}
Index: clang/lib/CodeGen/CodeGenModule.h
===
--- clang/lib/CodeGen/CodeGenModule.h
+++ clang/lib/CodeGen/CodeGenModule.h
@@ -1023,6 +1023,9 @@
/// for the uninstrumented functions.
void EmitDeferredUnusedCoverageMappings();
+ /// Emit an alias for "main" if it has no arguments (needed for wasm).
+ void EmitMainVoidAlias();
+
/// Tell the consumer that this variable has been instantiated.
void HandleCXXStaticMemberVarInstantiation(VarDecl *VD);
Index: clang/lib/CodeGen/CodeGenModule.cpp
===
--- clang/lib/CodeGen/CodeGenModule.cpp
+++ clang/lib/CodeGen/CodeGenModule.cpp
@@ -448,6 +448,10 @@
CodeGenFunction(*this).EmitCfiCheckStub();
}
emitAtAvailableLinkGuard();
+ if (Context.getTargetInfo().getTriple().isWasm() &&
+ !Context.getTargetInfo().getTriple().isOSEmscripten()) {
+EmitMainVoidAlias();
+ }
emitLLVMUsed();
if (SanStats)
SanStats->finish();
@@ -5600,6 +5604,17 @@
}
}
+void CodeGenModule::EmitMainVoidAlias() {
+ // In order to transition away from "__original_main" gracefully, emit an
+ // alias for "main" in the no-argument case so that libc can detect when
+ // new-style no-argument main is in used.
+ if (llvm::Function *F = getModule().getFunction("main")) {
+if (!F->isDeclaration() && F->arg_size() == 0 && !F->isVarArg() &&
+F->getReturnType()->isIntegerTy(Context.getTargetInfo().getIntWidth()))
+ addUsedGlobal(llvm::GlobalAlias::create("__main_void", F));
+ }
+}
+
/// Turns the given pointer into a constant.
static llvm::Constant *GetPointerConstant(llvm::LLVMContext ,
const void *Ptr) {
Index: clang/lib/AST/Mangle.cpp
===
--- clang/lib/AST/Mangle.cpp
+++ clang/lib/AST/Mangle.cpp
@@ -50,7 +50,8 @@
CCM_Fast,
CCM_RegCall,
CCM_Vector,
- CCM_Std
+ CCM_Std,
+ CCM_WasmMainArgcArgv
};
static bool isExternC(const NamedDecl *ND) {
@@ -63,6 +64,16 @@
const NamedDecl *ND) {
const TargetInfo = Context.getTargetInfo();
const llvm::Triple = TI.getTriple();
+
+ // On wasm, the argc/argv form of "main" is renamed so that the startup code
+ // can call it with the correct function signature.
+ // On Emscripten, users may be exporting "main" and expecting to call it
+ // themselves, so we can't mangle it.
+ if (Triple.isWasm() && !Triple.isOSEmscripten())
+if (const FunctionDecl *FD = dyn_cast(ND))
+ if
