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THIS IS A WIP!
Remove the restrictions that preventing "callbr" from returning non-void
values. The value returned by "callbr" is only valid on the "normal" path.
Values used on "abnormal" paths are poisoned.
Allow output constraints on "asm goto"
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D69875
Files:
clang/include/clang/AST/Stmt.h
clang/lib/AST/Stmt.cpp
clang/lib/Parse/ParseStmtAsm.cpp
clang/lib/Sema/SemaStmtAsm.cpp
clang/test/Parser/asm-goto.c
clang/test/Parser/asm-goto.cpp
llvm/lib/AsmParser/LLParser.cpp
llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
llvm/lib/IR/Verifier.cpp
llvm/test/CodeGen/X86/callbr-asm-outputs.ll
Index: llvm/test/CodeGen/X86/callbr-asm-outputs.ll
===================================================================
--- llvm/test/CodeGen/X86/callbr-asm-outputs.ll
+++ llvm/test/CodeGen/X86/callbr-asm-outputs.ll
@@ -1,18 +1,26 @@
-; RUN: not llc -mtriple=i686-- < %s 2> %t
-; RUN: FileCheck %s < %t
+; RUN: llc -mtriple=i686-- < %s | FileCheck %s
-; CHECK: error: asm-goto outputs not supported
+; A test for asm-goto output
-; A test for asm-goto output prohibition
-
-define i32 @test(i32 %a) {
+; CHECK-LABEL: test1:
+; CHECK: movl 4(%esp), %eax
+; CHECK-NEXT: addl $4, %eax
+; CHECK-NEXT: #APP
+; CHECK-NEXT: xorl %eax, %eax
+; CHECK-NEXT: jmp .Ltmp0
+; CHECK-NEXT: #NO_APP
+; CHECK-NEXT: .LBB0_1:
+; CHECK-NEXT: retl
+; CHECK-NEXT: .Ltmp0:
+define i32 @test1(i32 %x) {
entry:
- %0 = add i32 %a, 4
- %1 = callbr i32 asm "xorl $1, $1; jmp ${1:l}", "=&r,r,X,~{dirflag},~{fpsr},~{flags}"(i32 %0, i8* blockaddress(@test, %fail)) to label %normal [label %fail]
+ %add = add nsw i32 %x, 4
+ %ret = callbr i32 asm "xorl $1, $0; jmp ${2:l}", "=r,r,X,~{dirflag},~{fpsr},~{flags}"(i32 %add, i8* blockaddress(@test1, %abnormal))
+ to label %normal [label %abnormal]
normal:
- ret i32 %1
+ ret i32 %ret
-fail:
+abnormal:
ret i32 1
}
Index: llvm/lib/IR/Verifier.cpp
===================================================================
--- llvm/lib/IR/Verifier.cpp
+++ llvm/lib/IR/Verifier.cpp
@@ -2492,8 +2492,6 @@
void Verifier::visitCallBrInst(CallBrInst &CBI) {
Assert(CBI.isInlineAsm(), "Callbr is currently only used for asm-goto!",
&CBI);
- Assert(CBI.getType()->isVoidTy(), "Callbr return value is not supported!",
- &CBI);
for (unsigned i = 0, e = CBI.getNumSuccessors(); i != e; ++i)
Assert(CBI.getSuccessor(i)->getType()->isLabelTy(),
"Callbr successors must all have pointer type!", &CBI);
Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -2834,6 +2834,7 @@
assert(isa<InlineAsm>(I.getCalledValue()) &&
"Only know how to handle inlineasm callbr");
visitInlineAsm(&I);
+ CopyToExportRegsIfNeeded(&I);
// Retrieve successors.
MachineBasicBlock *Return = FuncInfo.MBBMap[I.getDefaultDest()];
Index: llvm/lib/AsmParser/LLParser.cpp
===================================================================
--- llvm/lib/AsmParser/LLParser.cpp
+++ llvm/lib/AsmParser/LLParser.cpp
@@ -6416,9 +6416,6 @@
/*IsCall=*/true))
return true;
- if (isa<InlineAsm>(Callee) && !Ty->getReturnType()->isVoidTy())
- return Error(RetTypeLoc, "asm-goto outputs not supported");
-
// Set up the Attribute for the function.
SmallVector<Value *, 8> Args;
SmallVector<AttributeSet, 8> ArgAttrs;
Index: clang/test/Parser/asm-goto.cpp
===================================================================
--- clang/test/Parser/asm-goto.cpp
+++ clang/test/Parser/asm-goto.cpp
@@ -6,9 +6,7 @@
int x,cond,*e;
// expected-error@+1 {{expected ')'}}
asm ("mov %[e], %[e]" : : [e] "rm" (*e)::a)
- // expected-error@+1 {{'asm goto' cannot have output constraints}}
- asm goto ("decl %0; jnz %l[a]" :"=r"(x): "m"(x) : "memory" : a);
- // expected-error@+1 {{expected identifie}}
+ // expected-error@+1 {{expected identifier}}
asm goto ("decl %0;" :: "m"(x) : "memory" : );
// expected-error@+1 {{expected ':'}}
asm goto ("decl %0;" :: "m"(x) : "memory" );
@@ -51,3 +49,12 @@
:: lab);
lab: return;
}
+
+int
+fgoto3 (int x)
+{
+ __asm__ volatile goto ("decl %0; jnz %l[a]"
+ : "=r" (x) : "m" (x) : "memory" : a);
+a:
+ return -x;
+}
Index: clang/test/Parser/asm-goto.c
===================================================================
--- clang/test/Parser/asm-goto.c
+++ clang/test/Parser/asm-goto.c
@@ -31,14 +31,22 @@
lab: return;
}
-int zoo ()
+int
+fgoto3 (int x)
+{
+ __asm__ volatile goto ("decl %0; jnz %l[a]"
+ : "=r" (x) : "m" (x) : "memory" : a);
+a:
+ return -x;
+}
+
+int
+zoo (void)
{
int x,cond,*e;
// expected-error@+1 {{expected ')'}}
asm ("mov %[e], %[e]" : : [e] "rm" (*e)::a)
- // expected-error@+1 {{'asm goto' cannot have output constraints}}
- asm goto ("decl %0; jnz %l[a]" :"=r"(x): "m"(x) : "memory" : a);
- // expected-error@+1 {{expected identifie}}
+ // expected-error@+1 {{expected identifier}}
asm goto ("decl %0;" :: "m"(x) : "memory" : );
// expected-error@+1 {{expected ':'}}
asm goto ("decl %0;" :: "m"(x) : "memory" );
Index: clang/lib/Sema/SemaStmtAsm.cpp
===================================================================
--- clang/lib/Sema/SemaStmtAsm.cpp
+++ clang/lib/Sema/SemaStmtAsm.cpp
@@ -473,10 +473,10 @@
// Look for the correct constraint index.
unsigned ConstraintIdx = Piece.getOperandNo();
- // Labels are the last in the Exprs list.
- if (NS->isAsmGoto() && ConstraintIdx >= NS->getNumInputs())
- continue;
unsigned NumOperands = NS->getNumOutputs() + NS->getNumInputs();
+ // Labels are the last in the Exprs list.
+ if (NS->isAsmGoto() && ConstraintIdx >= NumOperands)
+ continue;
// Look for the (ConstraintIdx - NumOperands + 1)th constraint with
// modifier '+'.
if (ConstraintIdx >= NumOperands) {
Index: clang/lib/Parse/ParseStmtAsm.cpp
===================================================================
--- clang/lib/Parse/ParseStmtAsm.cpp
+++ clang/lib/Parse/ParseStmtAsm.cpp
@@ -764,12 +764,6 @@
AteExtraColon = Tok.is(tok::coloncolon);
ConsumeToken();
- if (!AteExtraColon && isGotoAsm && Tok.isNot(tok::colon)) {
- Diag(Tok, diag::err_asm_goto_cannot_have_output);
- SkipUntil(tok::r_paren, StopAtSemi);
- return StmtError();
- }
-
if (!AteExtraColon && ParseAsmOperandsOpt(Names, Constraints, Exprs))
return StmtError();
}
Index: clang/lib/AST/Stmt.cpp
===================================================================
--- clang/lib/AST/Stmt.cpp
+++ clang/lib/AST/Stmt.cpp
@@ -456,7 +456,7 @@
}
AddrLabelExpr *GCCAsmStmt::getLabelExpr(unsigned i) const {
- return cast<AddrLabelExpr>(Exprs[i + NumInputs]);
+ return cast<AddrLabelExpr>(Exprs[i + NumOutputs + NumInputs]);
}
StringRef GCCAsmStmt::getLabelName(unsigned i) const {
@@ -522,7 +522,7 @@
for (unsigned i = 0, e = getNumLabels(); i != e; ++i)
if (getLabelName(i) == SymbolicName)
- return i + getNumInputs();
+ return i + getNumOutputs() + getNumInputs();
// Not found.
return -1;
Index: clang/include/clang/AST/Stmt.h
===================================================================
--- clang/include/clang/AST/Stmt.h
+++ clang/include/clang/AST/Stmt.h
@@ -3013,7 +3013,7 @@
}
IdentifierInfo *getLabelIdentifier(unsigned i) const {
- return Names[i + NumInputs];
+ return Names[i + NumOutputs + NumInputs];
}
AddrLabelExpr *getLabelExpr(unsigned i) const;
@@ -3024,11 +3024,11 @@
using labels_const_range = llvm::iterator_range<const_labels_iterator>;
labels_iterator begin_labels() {
- return &Exprs[0] + NumInputs;
+ return &Exprs[0] + NumOutputs + NumInputs;
}
labels_iterator end_labels() {
- return &Exprs[0] + NumInputs + NumLabels;
+ return &Exprs[0] + NumOutputs + NumInputs + NumLabels;
}
labels_range labels() {
@@ -3036,11 +3036,11 @@
}
const_labels_iterator begin_labels() const {
- return &Exprs[0] + NumInputs;
+ return &Exprs[0] + NumOutputs + NumInputs;
}
const_labels_iterator end_labels() const {
- return &Exprs[0] + NumInputs + NumLabels;
+ return &Exprs[0] + NumOutputs + NumInputs + NumLabels;
}
labels_const_range labels() const {
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