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Reduce the number of memory allocations when displaying

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a warning about clobbering reserved registers (NFC).

Also address some minor inefficiencies and style issues.

Differential Revision: https://reviews.llvm.org/D86088
This commit is contained in:
Momchil Velikov 2020-09-07 16:16:52 +01:00
parent 8248c2af94
commit eb482afaf5
1 changed files with 19 additions and 16 deletions
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35
llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
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@ -11,6 +11,7 @@
//===----------------------------------------------------------------------===//
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Twine.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
@ -547,22 +548,23 @@ void AsmPrinter::emitInlineAsm(const MachineInstr *MI) const {
EmitMSInlineAsmStr(AsmStr, MI, MMI, AP, LocCookie, OS);
// Emit warnings if we use reserved registers on the clobber list, as
// that might give surprising results.
std::vector<std::string> RestrRegs;
// that might lead to undefined behaviour.
SmallVector<Register, 8> RestrRegs;
const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
// Start with the first operand descriptor, and iterate over them.
for (unsigned I = InlineAsm::MIOp_FirstOperand, NumOps = MI->getNumOperands();
I < NumOps; ++I) {
const MachineOperand &MO = MI->getOperand(I);
if (MO.isImm()) {
unsigned Flags = MO.getImm();
const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
if (InlineAsm::getKind(Flags) == InlineAsm::Kind_Clobber &&
!TRI->isAsmClobberable(*MF, MI->getOperand(I + 1).getReg())) {
RestrRegs.push_back(TRI->getName(MI->getOperand(I + 1).getReg()));
}
// Skip to one before the next operand descriptor, if it exists.
I += InlineAsm::getNumOperandRegisters(Flags);
if (!MO.isImm())
continue;
unsigned Flags = MO.getImm();
if (InlineAsm::getKind(Flags) == InlineAsm::Kind_Clobber) {
Register Reg = MI->getOperand(I + 1).getReg();
if (!TRI->isAsmClobberable(*MF, Reg))
RestrRegs.push_back(Reg);
}
// Skip to one before the next operand descriptor, if it exists.
I += InlineAsm::getNumOperandRegisters(Flags);
}
if (!RestrRegs.empty()) {
@ -572,14 +574,15 @@ void AsmPrinter::emitInlineAsm(const MachineInstr *MI) const {
SrcMgr.getMemoryBuffer(BufNum)->getBuffer().begin());
std::string Msg = "inline asm clobber list contains reserved registers: ";
for (auto I = RestrRegs.begin(), E = RestrRegs.end(); I != E; I++) {
for (auto I = RestrRegs.begin(), E = RestrRegs.end(); I != E; ++I) {
if(I != RestrRegs.begin())
Msg += ", ";
Msg += *I;
Msg += TRI->getName(*I);
}
std::string Note = "Reserved registers on the clobber list may not be "
"preserved across the asm statement, and clobbering them may "
"lead to undefined behaviour.";
const char *Note =
"Reserved registers on the clobber list may not be "
"preserved across the asm statement, and clobbering them may "
"lead to undefined behaviour.";
SrcMgr.PrintMessage(Loc, SourceMgr::DK_Warning, Msg);
SrcMgr.PrintMessage(Loc, SourceMgr::DK_Note, Note);
}