[llvm] r319586 - [MC] Handle unknown literal register numbers in .cfi_* directives
Jake Ehrlich via llvm-commits
llvm-commits at lists.llvm.org
Fri Dec 1 13:44:28 PST 2017
Author: jakehehrlich
Date: Fri Dec 1 13:44:27 2017
New Revision: 319586
URL: http://llvm.org/viewvc/llvm-project?rev=319586&view=rev
Log:
[MC] Handle unknown literal register numbers in .cfi_* directives
r230670 introduced a step to map EH register numbers to standard
DWARF register numbers. This failed to consider the case when a
user .cfi_* directive uses an integer literal rather than a
register name, to specify a DWARF register number that has no
corresponding LLVM register number (e.g. a special register that
the compiler and assembler have no name for).
Fixes PR34028.
Patch by Roland McGrath
Differential Revision: https://reviews.llvm.org/D36493
Added:
llvm/trunk/test/MC/AsmParser/cfi-unknown-register.s
Modified:
llvm/trunk/include/llvm/MC/MCRegisterInfo.h
llvm/trunk/lib/MC/MCAsmStreamer.cpp
llvm/trunk/lib/MC/MCDwarf.cpp
llvm/trunk/lib/MC/MCRegisterInfo.cpp
Modified: llvm/trunk/include/llvm/MC/MCRegisterInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCRegisterInfo.h?rev=319586&r1=319585&r2=319586&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCRegisterInfo.h (original)
+++ llvm/trunk/include/llvm/MC/MCRegisterInfo.h Fri Dec 1 13:44:27 2017
@@ -407,6 +407,15 @@ public:
/// \brief Map a dwarf register back to a target register.
int getLLVMRegNum(unsigned RegNum, bool isEH) const;
+ /// \brief Map a DWARF EH register back to a target register (same as
+ /// getLLVMRegNum(RegNum, true)) but return -1 if there is no mapping,
+ /// rather than asserting that there must be one.
+ int getLLVMRegNumFromEH(unsigned RegNum) const;
+
+ /// \brief Map a target EH register number to an equivalent DWARF register
+ /// number.
+ int getDwarfRegNumFromDwarfEHRegNum(unsigned RegNum) const;
+
/// \brief Map a target register to an equivalent SEH register
/// number. Returns LLVM register number if there is no equivalent value.
int getSEHRegNum(unsigned RegNum) const;
Modified: llvm/trunk/lib/MC/MCAsmStreamer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCAsmStreamer.cpp?rev=319586&r1=319585&r2=319586&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCAsmStreamer.cpp (original)
+++ llvm/trunk/lib/MC/MCAsmStreamer.cpp Fri Dec 1 13:44:27 2017
@@ -1296,12 +1296,17 @@ void MCAsmStreamer::EmitCFIEndProcImpl(M
void MCAsmStreamer::EmitRegisterName(int64_t Register) {
if (!MAI->useDwarfRegNumForCFI()) {
+ // User .cfi_* directives can use arbitrary DWARF register numbers, not
+ // just ones that map to LLVM register numbers and have known names.
+ // Fall back to using the original number directly if no name is known.
const MCRegisterInfo *MRI = getContext().getRegisterInfo();
- unsigned LLVMRegister = MRI->getLLVMRegNum(Register, true);
- InstPrinter->printRegName(OS, LLVMRegister);
- } else {
- OS << Register;
+ int LLVMRegister = MRI->getLLVMRegNumFromEH(Register);
+ if (LLVMRegister != -1) {
+ InstPrinter->printRegName(OS, LLVMRegister);
+ return;
+ }
}
+ OS << Register;
}
void MCAsmStreamer::EmitCFIDefCfa(int64_t Register, int64_t Offset) {
Modified: llvm/trunk/lib/MC/MCDwarf.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCDwarf.cpp?rev=319586&r1=319585&r2=319586&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCDwarf.cpp (original)
+++ llvm/trunk/lib/MC/MCDwarf.cpp Fri Dec 1 13:44:27 2017
@@ -1057,8 +1057,8 @@ void FrameEmitterImpl::EmitCFIInstructio
unsigned Reg1 = Instr.getRegister();
unsigned Reg2 = Instr.getRegister2();
if (!IsEH) {
- Reg1 = MRI->getDwarfRegNum(MRI->getLLVMRegNum(Reg1, true), false);
- Reg2 = MRI->getDwarfRegNum(MRI->getLLVMRegNum(Reg2, true), false);
+ Reg1 = MRI->getDwarfRegNumFromDwarfEHRegNum(Reg1);
+ Reg2 = MRI->getDwarfRegNumFromDwarfEHRegNum(Reg2);
}
Streamer.EmitIntValue(dwarf::DW_CFA_register, 1);
Streamer.EmitULEB128IntValue(Reg1);
@@ -1094,7 +1094,7 @@ void FrameEmitterImpl::EmitCFIInstructio
case MCCFIInstruction::OpDefCfa: {
unsigned Reg = Instr.getRegister();
if (!IsEH)
- Reg = MRI->getDwarfRegNum(MRI->getLLVMRegNum(Reg, true), false);
+ Reg = MRI->getDwarfRegNumFromDwarfEHRegNum(Reg);
Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
Streamer.EmitULEB128IntValue(Reg);
CFAOffset = -Instr.getOffset();
@@ -1105,7 +1105,7 @@ void FrameEmitterImpl::EmitCFIInstructio
case MCCFIInstruction::OpDefCfaRegister: {
unsigned Reg = Instr.getRegister();
if (!IsEH)
- Reg = MRI->getDwarfRegNum(MRI->getLLVMRegNum(Reg, true), false);
+ Reg = MRI->getDwarfRegNumFromDwarfEHRegNum(Reg);
Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
Streamer.EmitULEB128IntValue(Reg);
@@ -1118,7 +1118,7 @@ void FrameEmitterImpl::EmitCFIInstructio
unsigned Reg = Instr.getRegister();
if (!IsEH)
- Reg = MRI->getDwarfRegNum(MRI->getLLVMRegNum(Reg, true), false);
+ Reg = MRI->getDwarfRegNumFromDwarfEHRegNum(Reg);
int Offset = Instr.getOffset();
if (IsRelative)
@@ -1154,7 +1154,7 @@ void FrameEmitterImpl::EmitCFIInstructio
case MCCFIInstruction::OpRestore: {
unsigned Reg = Instr.getRegister();
if (!IsEH)
- Reg = MRI->getDwarfRegNum(MRI->getLLVMRegNum(Reg, true), false);
+ Reg = MRI->getDwarfRegNumFromDwarfEHRegNum(Reg);
Streamer.EmitIntValue(dwarf::DW_CFA_restore | Reg, 1);
return;
}
Modified: llvm/trunk/lib/MC/MCRegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCRegisterInfo.cpp?rev=319586&r1=319585&r2=319586&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCRegisterInfo.cpp (original)
+++ llvm/trunk/lib/MC/MCRegisterInfo.cpp Fri Dec 1 13:44:27 2017
@@ -88,6 +88,34 @@ int MCRegisterInfo::getLLVMRegNum(unsign
return I->ToReg;
}
+int MCRegisterInfo::getLLVMRegNumFromEH(unsigned RegNum) const {
+ const DwarfLLVMRegPair *M = EHDwarf2LRegs;
+ unsigned Size = EHDwarf2LRegsSize;
+
+ if (!M)
+ return -1;
+ DwarfLLVMRegPair Key = { RegNum, 0 };
+ const DwarfLLVMRegPair *I = std::lower_bound(M, M+Size, Key);
+ if (I == M+Size || I->FromReg != RegNum)
+ return -1;
+ return I->ToReg;
+}
+
+int MCRegisterInfo::getDwarfRegNumFromDwarfEHRegNum(unsigned RegNum) const {
+ // On ELF platforms, DWARF EH register numbers are the same as DWARF
+ // other register numbers. On Darwin x86, they differ and so need to be
+ // mapped. The .cfi_* directives accept integer literals as well as
+ // register names and should generate exactly what the assembly code
+ // asked for, so there might be DWARF/EH register numbers that don't have
+ // a corresponding LLVM register number at all. So if we can't map the
+ // EH register number to an LLVM register number, assume it's just a
+ // valid DWARF register number as is.
+ int LRegNum = getLLVMRegNumFromEH(RegNum);
+ if (LRegNum != -1)
+ return getDwarfRegNum(LRegNum, false);
+ return RegNum;
+}
+
int MCRegisterInfo::getSEHRegNum(unsigned RegNum) const {
const DenseMap<unsigned, int>::const_iterator I = L2SEHRegs.find(RegNum);
if (I == L2SEHRegs.end()) return (int)RegNum;
Added: llvm/trunk/test/MC/AsmParser/cfi-unknown-register.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/AsmParser/cfi-unknown-register.s?rev=319586&view=auto
==============================================================================
--- llvm/trunk/test/MC/AsmParser/cfi-unknown-register.s (added)
+++ llvm/trunk/test/MC/AsmParser/cfi-unknown-register.s Fri Dec 1 13:44:27 2017
@@ -0,0 +1,7 @@
+// RUN: llvm-mc -filetype=asm -triple x86_64-pc-linux-gnu %s 2>&1 | FileCheck %s
+
+.cfi_sections .debug_frame
+.cfi_startproc
+.cfi_rel_offset 99, 0
+// CHECK: .cfi_rel_offset 99, 0
+.cfi_endproc
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