[llvm] r343640 - [WebAssembly] Stop generating helper functions in WebAssemblyLowerEmscriptenEHSjLj
Sam Clegg via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 2 15:12:15 PDT 2018
Author: sbc
Date: Tue Oct 2 15:12:15 2018
New Revision: 343640
URL: http://llvm.org/viewvc/llvm-project?rev=343640&view=rev
Log:
[WebAssembly] Stop generating helper functions in WebAssemblyLowerEmscriptenEHSjLj
Previously we were creating weakly defined helper function in
each translation unit:
- setThrew
- setTempRet0
Instead we now assume these will be provided at link time. In
emscripten they are provided in compiler-rt:
https://github.com/kripken/emscripten/pull/7203
Additionally we previously created three global variable which are
also now required to exist at link time instead.
- __THREW__
- _threwValue
- __tempRet0
Differential Revision: https://reviews.llvm.org/D49208
Modified:
llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions.ll
llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll
Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp?rev=343640&r1=343639&r2=343640&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp (original)
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp Tue Oct 2 15:12:15 2018
@@ -50,7 +50,8 @@
///
/// In detail, this pass does following things:
///
-/// 1) Create three global variables: __THREW__, __threwValue, and __tempRet0.
+/// 1) Assumes the existence of global variables: __THREW__, __threwValue, and
+/// __tempRet0.
/// __tempRet0 will be set within __cxa_find_matching_catch() function in
/// JS library, and __THREW__ and __threwValue will be set in invoke wrappers
/// in JS glue code. For what invoke wrappers are, refer to 3). These
@@ -65,9 +66,10 @@
///
/// * Exception handling
///
-/// 2) Create setThrew and setTempRet0 functions.
-/// The global variables created in 1) will exist in wasm address space,
-/// but their values should be set in JS code, so we provide these functions
+/// 2) We assume the existence of setThrew and setTempRet0 functions at link
+/// time.
+/// The global variables in 1) will exist in wasm address space,
+/// but their values should be set in JS code, so these functions
/// as interfaces to JS glue code. These functions are equivalent to the
/// following JS functions, which actually exist in asm.js version of JS
/// library.
@@ -272,9 +274,6 @@ class WebAssemblyLowerEmscriptenEHSjLj f
bool areAllExceptionsAllowed() const { return EHWhitelistSet.empty(); }
bool canLongjmp(Module &M, const Value *Callee) const;
- void createSetThrewFunction(Module &M);
- void createSetTempRet0Function(Module &M);
-
void rebuildSSA(Function &F);
public:
@@ -333,13 +332,15 @@ static bool canThrow(const Value *V) {
return true;
}
-static GlobalVariable *createGlobalVariableI32(Module &M, IRBuilder<> &IRB,
- const char *Name) {
+// Get a global variable with the given name. If it doesn't exist declare it,
+// which will generate an import and asssumes that it will exist at link time.
+static GlobalVariable *getGlobalVariableI32(Module &M, IRBuilder<> &IRB,
+ const char *Name) {
if (M.getNamedGlobal(Name))
report_fatal_error(Twine("variable name is reserved: ") + Name);
return new GlobalVariable(M, IRB.getInt32Ty(), false,
- GlobalValue::WeakODRLinkage, IRB.getInt32(0), Name);
+ GlobalValue::ExternalLinkage, nullptr, Name);
}
// Simple function name mangler.
@@ -590,67 +591,6 @@ void WebAssemblyLowerEmscriptenEHSjLj::w
LongjmpResult = IRB.CreateLoad(TempRet0GV, "longjmp_result");
}
-// Create setThrew function
-// function setThrew(threw, value) {
-// if (__THREW__ == 0) {
-// __THREW__ = threw;
-// __threwValue = value;
-// }
-// }
-void WebAssemblyLowerEmscriptenEHSjLj::createSetThrewFunction(Module &M) {
- LLVMContext &C = M.getContext();
- IRBuilder<> IRB(C);
-
- if (M.getNamedGlobal("setThrew"))
- report_fatal_error("setThrew already exists");
-
- Type *Params[] = {IRB.getInt32Ty(), IRB.getInt32Ty()};
- FunctionType *FTy = FunctionType::get(IRB.getVoidTy(), Params, false);
- Function *F =
- Function::Create(FTy, GlobalValue::WeakODRLinkage, "setThrew", &M);
- Argument *Arg1 = &*(F->arg_begin());
- Argument *Arg2 = &*std::next(F->arg_begin());
- Arg1->setName("threw");
- Arg2->setName("value");
- BasicBlock *EntryBB = BasicBlock::Create(C, "entry", F);
- BasicBlock *ThenBB = BasicBlock::Create(C, "if.then", F);
- BasicBlock *EndBB = BasicBlock::Create(C, "if.end", F);
-
- IRB.SetInsertPoint(EntryBB);
- Value *Threw = IRB.CreateLoad(ThrewGV, ThrewGV->getName() + ".val");
- Value *Cmp = IRB.CreateICmpEQ(Threw, IRB.getInt32(0), "cmp");
- IRB.CreateCondBr(Cmp, ThenBB, EndBB);
-
- IRB.SetInsertPoint(ThenBB);
- IRB.CreateStore(Arg1, ThrewGV);
- IRB.CreateStore(Arg2, ThrewValueGV);
- IRB.CreateBr(EndBB);
-
- IRB.SetInsertPoint(EndBB);
- IRB.CreateRetVoid();
-}
-
-// Create setTempRet0 function
-// function setTempRet0(value) {
-// __tempRet0 = value;
-// }
-void WebAssemblyLowerEmscriptenEHSjLj::createSetTempRet0Function(Module &M) {
- LLVMContext &C = M.getContext();
- IRBuilder<> IRB(C);
-
- if (M.getNamedGlobal("setTempRet0"))
- report_fatal_error("setTempRet0 already exists");
- Type *Params[] = {IRB.getInt32Ty()};
- FunctionType *FTy = FunctionType::get(IRB.getVoidTy(), Params, false);
- Function *F =
- Function::Create(FTy, GlobalValue::WeakODRLinkage, "setTempRet0", &M);
- F->arg_begin()->setName("value");
- BasicBlock *EntryBB = BasicBlock::Create(C, "entry", F);
- IRB.SetInsertPoint(EntryBB);
- IRB.CreateStore(&*F->arg_begin(), TempRet0GV);
- IRB.CreateRetVoid();
-}
-
void WebAssemblyLowerEmscriptenEHSjLj::rebuildSSA(Function &F) {
DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
DT.recalculate(F); // CFG has been changed
@@ -688,11 +628,12 @@ bool WebAssemblyLowerEmscriptenEHSjLj::r
bool LongjmpUsed = LongjmpF && !LongjmpF->use_empty();
bool DoSjLj = EnableSjLj && (SetjmpUsed || LongjmpUsed);
- // Create global variables __THREW__, threwValue, and __tempRet0, which are
- // used in common for both exception handling and setjmp/longjmp handling
- ThrewGV = createGlobalVariableI32(M, IRB, "__THREW__");
- ThrewValueGV = createGlobalVariableI32(M, IRB, "__threwValue");
- TempRet0GV = createGlobalVariableI32(M, IRB, "__tempRet0");
+ // Declare (or get) global variables __THREW__, __threwValue, and __tempRet0,
+ // which are used in common for both exception handling and setjmp/longjmp
+ // handling
+ ThrewGV = getGlobalVariableI32(M, IRB, "__THREW__");
+ ThrewValueGV = getGlobalVariableI32(M, IRB, "__threwValue");
+ TempRet0GV = getGlobalVariableI32(M, IRB, "__tempRet0");
bool Changed = false;
@@ -764,9 +705,6 @@ bool WebAssemblyLowerEmscriptenEHSjLj::r
if (!Changed) {
// Delete unused global variables and functions
- ThrewGV->eraseFromParent();
- ThrewValueGV->eraseFromParent();
- TempRet0GV->eraseFromParent();
if (ResumeF)
ResumeF->eraseFromParent();
if (EHTypeIDF)
@@ -780,12 +718,6 @@ bool WebAssemblyLowerEmscriptenEHSjLj::r
return false;
}
- // If we have made any changes while doing exception handling or
- // setjmp/longjmp handling, we have to create these functions for JavaScript
- // to call.
- createSetThrewFunction(M);
- createSetTempRet0Function(M);
-
return true;
}
Modified: llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions.ll?rev=343640&r1=343639&r2=343640&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions.ll (original)
+++ llvm/trunk/test/CodeGen/WebAssembly/lower-em-exceptions.ll Tue Oct 2 15:12:15 2018
@@ -5,9 +5,9 @@ target triple = "wasm32-unknown-unknown"
@_ZTIi = external constant i8*
@_ZTIc = external constant i8*
-; CHECK-DAG: __THREW__ = weak_odr global i32 0
-; CHECK-DAG: __threwValue = weak_odr global i32 0
-; CHECK-DAG: __tempRet0 = weak_odr global i32 0
+; CHECK-DAG: __THREW__ = external global i32
+; CHECK-DAG: __threwValue = external global i32
+; CHECK-DAG: __tempRet0 = external global i32
; Test invoke instruction with clauses (try-catch block)
define void @clause() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
@@ -171,24 +171,3 @@ declare void @__cxa_call_unexpected(i8*)
; CHECK-DAG: declare void @__resumeException(i8*)
; CHECK-DAG: declare void @__invoke_void_i32(void (i32)*, i32)
; CHECK-DAG: declare i8* @__cxa_find_matching_catch_4(i8*, i8*)
-
-; setThrew function creation
-; CHECK-LABEL: define weak_odr void @setThrew(i32 %threw, i32 %value) {
-; CHECK: entry:
-; CHECK-NEXT: %__THREW__.val = load i32, i32* @__THREW__
-; CHECK-NEXT: %cmp = icmp eq i32 %__THREW__.val, 0
-; CHECK-NEXT: br i1 %cmp, label %if.then, label %if.end
-; CHECK: if.then:
-; CHECK-NEXT: store i32 %threw, i32* @__THREW__
-; CHECK-NEXT: store i32 %value, i32* @__threwValue
-; CHECK-NEXT: br label %if.end
-; CHECK: if.end:
-; CHECK-NEXT: ret void
-; CHECK: }
-
-; setTempRet0 function creation
-; CHECK-LABEL: define weak_odr void @setTempRet0(i32 %value) {
-; CHECK: entry:
-; CHECK-NEXT: store i32 %value, i32* @__tempRet0
-; CHECK-NEXT: ret void
-; CHECK: }
Modified: llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll?rev=343640&r1=343639&r2=343640&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll (original)
+++ llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll Tue Oct 2 15:12:15 2018
@@ -6,9 +6,9 @@ target triple = "wasm32-unknown-unknown"
%struct.__jmp_buf_tag = type { [6 x i32], i32, [32 x i32] }
@global_var = hidden global i32 0, align 4
-; CHECK-DAG: __THREW__ = weak_odr global i32 0
-; CHECK-DAG: __threwValue = weak_odr global i32 0
-; CHECK-DAG: __tempRet0 = weak_odr global i32 0
+; CHECK-DAG: __THREW__ = external global i32
+; CHECK-DAG: __threwValue = external global i32
+; CHECK-DAG: __tempRet0 = external global i32
; Test a simple setjmp - longjmp sequence
define hidden void @setjmp_longjmp() {
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