[llvm] r315326 - [WebAssembly] Narrow the scope of WebAssemblyFixFunctionBitcasts
Jacob Gravelle via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 10 09:20:18 PDT 2017
Author: jgravelle
Date: Tue Oct 10 09:20:18 2017
New Revision: 315326
URL: http://llvm.org/viewvc/llvm-project?rev=315326&view=rev
Log:
[WebAssembly] Narrow the scope of WebAssemblyFixFunctionBitcasts
Summary:
The pass to fix function bitcasts generates thunks for functions that
are called directly with a mismatching signature. It was also generating
thunks in cases where the function was address-taken, causing aliasing
problems in otherwise valid cases.
This patch tightens the restrictions for when the pass runs.
Reviewers: sunfish, dschuff
Subscribers: jfb, sbc100, llvm-commits, aheejin
Differential Revision: https://reviews.llvm.org/D38640
Modified:
llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts.ll
Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp?rev=315326&r1=315325&r2=315326&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp (original)
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp Tue Oct 10 09:20:18 2017
@@ -24,6 +24,7 @@
//===----------------------------------------------------------------------===//
#include "WebAssembly.h"
+#include "llvm/IR/CallSite.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Module.h"
@@ -68,10 +69,19 @@ static void FindUses(Value *V, Function
if (BitCastOperator *BC = dyn_cast<BitCastOperator>(U.getUser()))
FindUses(BC, F, Uses, ConstantBCs);
else if (U.get()->getType() != F.getType()) {
+ CallSite CS(U.getUser());
+ if (!CS)
+ // Skip uses that aren't immediately called
+ continue;
+ Value *Callee = CS.getCalledValue();
+ if (Callee != V)
+ // Skip calls where the function isn't the callee
+ continue;
if (isa<Constant>(U.get())) {
// Only add constant bitcasts to the list once; they get RAUW'd
auto c = ConstantBCs.insert(cast<Constant>(U.get()));
- if (!c.second) continue;
+ if (!c.second)
+ continue;
}
Uses.push_back(std::make_pair(&U, &F));
}
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=315326&r1=315325&r2=315326&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts.ll (original)
+++ llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts.ll Tue Oct 10 09:20:18 2017
@@ -1,10 +1,20 @@
-; RUN: llc < %s -asm-verbose=false -disable-wasm-explicit-locals | FileCheck %s
+; RUN: llc < %s -asm-verbose=false -disable-wasm-explicit-locals -enable-emscripten-cxx-exceptions | FileCheck %s
; Test that function pointer casts are replaced with wrappers.
target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32-unknown-unknown-wasm"
+declare void @has_i32_arg(i32)
+declare i32 @has_i32_ret()
+declare void @vararg(...)
+declare void @plain(i32)
+
+declare void @foo0()
+declare void @foo1()
+declare void @foo2()
+declare void @foo3()
+
; CHECK-LABEL: test:
; CHECK-NEXT: call .Lbitcast at FUNCTION{{$}}
; CHECK-NEXT: call .Lbitcast at FUNCTION{{$}}
@@ -21,6 +31,25 @@ target triple = "wasm32-unknown-unknown-
; CHECK-NEXT: call foo1 at FUNCTION{{$}}
; CHECK-NEXT: call foo3 at FUNCTION{{$}}
; CHECK-NEXT: end_function
+define void @test() {
+entry:
+ call void bitcast (void (i32)* @has_i32_arg to void ()*)()
+ call void bitcast (void (i32)* @has_i32_arg to void ()*)()
+ call void bitcast (i32 ()* @has_i32_ret to void ()*)()
+ call void bitcast (void ()* @foo0 to void (i32)*)(i32 0)
+ %p = bitcast void ()* @foo0 to void (i32)*
+ call void %p(i32 0)
+ %q = bitcast void ()* @foo0 to void (i32)*
+ call void %q(i32 0)
+ %r = bitcast void (i32)* %q to void ()*
+ call void %r()
+ %t = call i32 bitcast (void ()* @foo1 to i32 ()*)()
+ call void bitcast (void ()* @foo2 to void ()*)()
+ call void @foo1()
+ call void @foo3()
+
+ ret void
+}
; CHECK-LABEL: test_varargs:
; CHECK: set_global
@@ -29,6 +58,85 @@ target triple = "wasm32-unknown-unknown-
; 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, $[[L5]]{{$}}
+define void @test_varargs() {
+ call void bitcast (void (...)* @vararg to void (i32)*)(i32 0)
+ call void (...) bitcast (void (i32)* @plain to void (...)*)(i32 0)
+ ret void
+}
+
+; Don't use wrappers when the value is stored in memory
+
+ at global_func = hidden local_unnamed_addr global void ()* null
+
+; CHECK-LABEL: test_store:
+; CHECK-NEXT: i32.const $push[[L0:[0-9]+]]=, 0{{$}}
+; CHECK-NEXT: i32.const $push[[L1:[0-9]+]]=, has_i32_ret at FUNCTION{{$}}
+; CHECK-NEXT: i32.store global_func($pop[[L0]]), $pop[[L1]]{{$}}
+define void @test_store() {
+ %1 = bitcast i32 ()* @has_i32_ret to void ()*
+ store void ()* %1, void ()** @global_func
+ ret void
+}
+
+; CHECK-LABEL: test_load:
+; CHECK-NEXT: result i32{{$}}
+; CHECK-NEXT: i32.const $push[[L0:[0-9]+]]=, 0{{$}}
+; CHECK-NEXT: i32.load $push[[L1:[0-9]+]]=, global_func($pop[[L0]]){{$}}
+; CHECK-NEXT: i32.call_indirect $push{{[0-9]+}}=, $pop[[L1]]{{$}}
+define i32 @test_load() {
+ %1 = load i32 ()*, i32 ()** bitcast (void ()** @global_func to i32 ()**)
+ %2 = call i32 %1()
+ ret i32 %2
+}
+
+; Don't use wrappers when the value is passed to a function call
+
+declare void @call_func(i32 ()*)
+
+; CHECK-LABEL: test_argument:
+; CHECK-NEXT: i32.const $push[[L0:[0-9]+]]=, has_i32_ret at FUNCTION{{$}}
+; CHECK-NEXT: call call_func at FUNCTION, $pop[[L0]]{{$}}
+; CHECK-NEXT: i32.const $push[[L1:[0-9]+]]=, has_i32_arg at FUNCTION{{$}}
+; CHECK-NEXT: call call_func at FUNCTION, $pop[[L1]]{{$}}
+define void @test_argument() {
+ call void @call_func(i32 ()* @has_i32_ret)
+ call void @call_func(i32 ()* bitcast (void (i32)* @has_i32_arg to i32 ()*))
+ ret void
+}
+
+; Invokes should be treated like calls
+
+; CHECK-LABEL: test_invoke:
+; CHECK: i32.const $push[[L1:[0-9]+]]=, call_func at FUNCTION{{$}}
+; CHECK-NEXT: i32.const $push[[L0:[0-9]+]]=, has_i32_ret at FUNCTION{{$}}
+; CHECK-NEXT: call "__invoke_void_i32()*"@FUNCTION, $pop[[L1]], $pop[[L0]]{{$}}
+; CHECK: i32.const $push[[L3:[0-9]+]]=, call_func at FUNCTION{{$}}
+; CHECK-NEXT: i32.const $push[[L2:[0-9]+]]=, has_i32_arg at FUNCTION{{$}}
+; CHECK-NEXT: call "__invoke_void_i32()*"@FUNCTION, $pop[[L3]], $pop[[L2]]{{$}}
+; CHECK: i32.const $push[[L4:[0-9]+]]=, .Lbitcast at FUNCTION{{$}}
+; CHECK-NEXT: call __invoke_void at FUNCTION, $pop[[L4]]{{$}}
+declare i32 @personality(...)
+define void @test_invoke() personality i32 (...)* @personality {
+entry:
+ invoke void @call_func(i32 ()* @has_i32_ret)
+ to label %cont unwind label %lpad
+
+cont:
+ invoke void @call_func(i32 ()* bitcast (void (i32)* @has_i32_arg to i32 ()*))
+ to label %cont2 unwind label %lpad
+
+cont2:
+ invoke void bitcast (void (i32)* @has_i32_arg to void ()*)()
+ to label %end unwind label %lpad
+
+lpad:
+ %0 = landingpad { i8*, i32 }
+ catch i8* null
+ br label %end
+
+end:
+ ret void
+}
; CHECK-LABEL: .Lbitcast:
; CHECK-NEXT: call has_i32_arg at FUNCTION, $0{{$}}
@@ -48,39 +156,3 @@ target triple = "wasm32-unknown-unknown-
; CHECK-NEXT: call foo1 at FUNCTION{{$}}
; CHECK-NEXT: copy_local $push0=, $0
; CHECK-NEXT: end_function
-
-declare void @has_i32_arg(i32)
-declare i32 @has_i32_ret()
-declare void @vararg(...)
-declare void @plain(i32)
-
-declare void @foo0()
-declare void @foo1()
-declare void @foo2()
-declare void @foo3()
-
-define void @test() {
-entry:
- call void bitcast (void (i32)* @has_i32_arg to void ()*)()
- call void bitcast (void (i32)* @has_i32_arg to void ()*)()
- call void bitcast (i32 ()* @has_i32_ret to void ()*)()
- call void bitcast (void ()* @foo0 to void (i32)*)(i32 0)
- %p = bitcast void ()* @foo0 to void (i32)*
- call void %p(i32 0)
- %q = bitcast void ()* @foo0 to void (i32)*
- call void %q(i32 0)
- %r = bitcast void (i32)* %q to void ()*
- call void %r()
- %t = call i32 bitcast (void ()* @foo1 to i32 ()*)()
- call void bitcast (void ()* @foo2 to void ()*)()
- call void @foo1()
- call void @foo3()
-
- ret void
-}
-
-define void @test_varargs() {
- call void bitcast (void (...)* @vararg to void (i32)*)(i32 0)
- call void (...) bitcast (void (i32)* @plain to void (...)*)(i32 0)
- ret void
-}
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