[llvm] r319186 - [WebAssembly] Support bitcasted function addresses with varargs.
Dan Gohman via llvm-commits
llvm-commits at lists.llvm.org
Tue Nov 28 09:15:03 PST 2017
Author: djg
Date: Tue Nov 28 09:15:03 2017
New Revision: 319186
URL: http://llvm.org/viewvc/llvm-project?rev=319186&view=rev
Log:
[WebAssembly] Support bitcasted function addresses with varargs.
Generalize FixFunctionBitcasts to handle varargs functions. This in
particular fixes the case where clang bitcasts away a varargs when
calling a K&R-style function.
This avoids interacting with tricky ABI details because it operates
at the LLVM IR level before varargs ABI details are exposed.
This fixes PR35385.
Added:
llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts-varargs.ll
Modified:
llvm/trunk/lib/MC/WasmObjectWriter.cpp
llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
llvm/trunk/test/CodeGen/WebAssembly/call.ll
llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts.ll
Modified: llvm/trunk/lib/MC/WasmObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/WasmObjectWriter.cpp?rev=319186&r1=319185&r2=319186&view=diff
==============================================================================
--- llvm/trunk/lib/MC/WasmObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/WasmObjectWriter.cpp Tue Nov 28 09:15:03 2017
@@ -1040,12 +1040,15 @@ void WasmObjectWriter::writeObject(MCAss
for (const MCSymbol &S : Asm.symbols()) {
const auto &WS = static_cast<const MCSymbolWasm &>(S);
- if (WS.isTemporary())
- continue;
-
+ // Register types for all functions, including those with private linkage
+ // (making them
+ // because wasm always needs a type signature.
if (WS.isFunction())
registerFunctionType(WS);
+ if (WS.isTemporary())
+ continue;
+
// If the symbol is not defined in this translation unit, import it.
if (!WS.isDefined(/*SetUsed=*/false)) {
WasmImport Import;
Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp?rev=319186&r1=319185&r2=319186&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp (original)
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp Tue Nov 28 09:15:03 2017
@@ -107,9 +107,10 @@ static Function *CreateWrapper(Function
// Determine what arguments to pass.
SmallVector<Value *, 4> Args;
Function::arg_iterator AI = Wrapper->arg_begin();
+ Function::arg_iterator AE = Wrapper->arg_end();
FunctionType::param_iterator PI = F->getFunctionType()->param_begin();
FunctionType::param_iterator PE = F->getFunctionType()->param_end();
- for (; AI != Wrapper->arg_end() && PI != PE; ++AI, ++PI) {
+ for (; AI != AE && PI != PE; ++AI, ++PI) {
if (AI->getType() != *PI) {
Wrapper->eraseFromParent();
return nullptr;
@@ -118,6 +119,9 @@ static Function *CreateWrapper(Function
}
for (; PI != PE; ++PI)
Args.push_back(UndefValue::get(*PI));
+ if (F->isVarArg())
+ for (; AI != AE; ++AI)
+ Args.push_back(&*AI);
CallInst *Call = CallInst::Create(F, Args, "", BB);
@@ -158,11 +162,6 @@ bool FixFunctionBitcasts::runOnModule(Mo
if (!Ty)
continue;
- // Wasm varargs are not ABI-compatible with non-varargs. Just ignore
- // such casts for now.
- if (Ty->isVarArg() || F->isVarArg())
- continue;
-
auto Pair = Wrappers.insert(std::make_pair(std::make_pair(F, Ty), nullptr));
if (Pair.second)
Pair.first->second = CreateWrapper(F, Ty);
Modified: llvm/trunk/test/CodeGen/WebAssembly/call.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/call.ll?rev=319186&r1=319185&r2=319186&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/call.ll (original)
+++ llvm/trunk/test/CodeGen/WebAssembly/call.ll Tue Nov 28 09:15:03 2017
@@ -153,7 +153,7 @@ define void @coldcc_tail_call_void_nulla
; CHECK-LABEL: call_constexpr:
; CHECK-NEXT: i32.const $push[[L0:[0-9]+]]=, 2{{$}}
; CHECK-NEXT: i32.const $push[[L1:[0-9]+]]=, 3{{$}}
-; CHECK-NEXT: call vararg_func at FUNCTION, $pop[[L0]], $pop[[L1]]{{$}}
+; CHECK-NEXT: call .Lbitcast at FUNCTION, $pop[[L0]], $pop[[L1]]{{$}}
; CHECK-NEXT: call other_void_nullary at FUNCTION{{$}}
; CHECK-NEXT: call void_nullary at FUNCTION{{$}}
; CHECK-NEXT: return{{$}}
Added: llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts-varargs.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts-varargs.ll?rev=319186&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts-varargs.ll (added)
+++ llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts-varargs.ll Tue Nov 28 09:15:03 2017
@@ -0,0 +1,31 @@
+; RUN: llc < %s -asm-verbose=false | FileCheck %s
+
+; Test that function pointer casts casting away varargs are replaced with
+; wrappers.
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown-wasm"
+
+define void @callWithArgs() {
+entry:
+ call void bitcast (void (...)* @underspecified to void (i32, i32)*)(i32 0, i32 1)
+ call void(...) bitcast (void (i32, i32)* @specified to void (...)*)(i32 0, i32 1)
+ ret void
+}
+
+declare void @underspecified(...)
+declare void @specified(i32, i32)
+
+; CHECK: callWithArgs:
+; CHECK: i32.const $push1=, 0
+; CHECK-NEXT: i32.const $push0=, 1
+; CHECK-NEXT: call .Lbitcast at FUNCTION, $pop1, $pop0
+; CHECK: call .Lbitcast.1 at FUNCTION, $pop{{[0-9]+$}}
+
+; CHECK: .Lbitcast:
+; CHECK-NEXT: .param i32, i32{{$}}
+; CHECK: call underspecified at FUNCTION, $pop{{[0-9]+$}}
+
+; CHECK: .Lbitcast.1:
+; CHECK-NEXT: .param i32{{$}}
+; CHECK: call specified at FUNCTION, $pop{{[0-9]+}}, $pop{{[0-9]+$}}
Modified: llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts.ll?rev=319186&r1=319185&r2=319186&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts.ll (original)
+++ llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts.ll Tue Nov 28 09:15:03 2017
@@ -20,13 +20,13 @@ declare void @foo3()
; CHECK-NEXT: call .Lbitcast at FUNCTION{{$}}
; CHECK-NEXT: call .Lbitcast.1 at FUNCTION{{$}}
; CHECK-NEXT: i32.const $push[[L0:[0-9]+]]=, 0
-; CHECK-NEXT: call .Lbitcast.2 at FUNCTION, $pop[[L0]]{{$}}
+; CHECK-NEXT: call .Lbitcast.4 at FUNCTION, $pop[[L0]]{{$}}
; CHECK-NEXT: i32.const $push[[L1:[0-9]+]]=, 0
-; CHECK-NEXT: call .Lbitcast.2 at FUNCTION, $pop[[L1]]{{$}}
+; CHECK-NEXT: call .Lbitcast.4 at FUNCTION, $pop[[L1]]{{$}}
; CHECK-NEXT: i32.const $push[[L2:[0-9]+]]=, 0
-; CHECK-NEXT: call .Lbitcast.2 at FUNCTION, $pop[[L2]]{{$}}
+; CHECK-NEXT: call .Lbitcast.4 at FUNCTION, $pop[[L2]]{{$}}
; CHECK-NEXT: call foo0 at FUNCTION
-; CHECK-NEXT: i32.call $drop=, .Lbitcast.3 at FUNCTION{{$}}
+; CHECK-NEXT: i32.call $drop=, .Lbitcast.5 at FUNCTION{{$}}
; CHECK-NEXT: call foo2 at FUNCTION{{$}}
; CHECK-NEXT: call foo1 at FUNCTION{{$}}
; CHECK-NEXT: call foo3 at FUNCTION{{$}}
@@ -54,10 +54,10 @@ entry:
; CHECK-LABEL: test_varargs:
; CHECK: set_global
; CHECK: i32.const $push[[L3:[0-9]+]]=, 0{{$}}
-; CHECK-NEXT: call vararg at FUNCTION, $pop[[L3]]{{$}}
+; CHECK-NEXT: call .Lbitcast.2 at FUNCTION, $pop[[L3]]{{$}}
; CHECK-NEXT: i32.const $push[[L4:[0-9]+]]=, 0{{$}}
; CHECK-NEXT: i32.store 0($[[L5:[0-9]+]]), $pop[[L4]]{{$}}
-; CHECK-NEXT: call plain at FUNCTION, $[[L5]]{{$}}
+; CHECK-NEXT: call .Lbitcast.3 at FUNCTION, $[[L5]]{{$}}
define void @test_varargs() {
call void bitcast (void (...)* @vararg to void (i32)*)(i32 0)
call void (...) bitcast (void (i32)* @plain to void (...)*)(i32 0)
@@ -147,11 +147,19 @@ end:
; CHECK-NEXT: end_function
; CHECK-LABEL: .Lbitcast.2:
+; CHECK: call vararg at FUNCTION, $1{{$}}
+; CHECK: end_function
+
+; CHECK-LABEL: .Lbitcast.3:
+; CHECK: call plain at FUNCTION, $1{{$}}
+; CHECK: end_function
+
+; CHECK-LABEL: .Lbitcast.4:
; CHECK-NEXT: .param i32
; CHECK-NEXT: call foo0 at FUNCTION{{$}}
; CHECK-NEXT: end_function
-; CHECK-LABEL: .Lbitcast.3:
+; CHECK-LABEL: .Lbitcast.5:
; CHECK-NEXT: .result i32
; CHECK-NEXT: call foo1 at FUNCTION{{$}}
; CHECK-NEXT: copy_local $push0=, $0
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