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Differential D82692

[ARM] do not consider sp as deprecated for ldm/stm
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Authored by falstaff84 on Jun 26 2020, 4:43 PM.

Details

Reviewers
psmith
simon_tatham
efriedma
SjoerdMeijer
Commits
rGe1c3bf6afe09: [ARM] do not consider sp as deprecated for ldm/stm
Summary

Early versions of the ARMv7 reference manuals considered the sp register
as a deprecated register for ldm/stm familiy of instructions. However,
later versions such as ARM DDI 0406C.d added a note to the Appendix:

D9.3 Use of the SP as a general-purpose register

Most ARM instructions, unlike Thumb instructions, provide exactly the
same access to the SP as to R0-R12. This means that it is possible to
use the SP as a general-purpose register.  Earlier issues of this manual
deprecated the use of SP in an ARM instruction, in any way that is
deprecated, not permitted, or not possible in the corresponding
Thumb instruction. However, user feedback indicates a number of cases
where these instructions are useful. Therefore, ARM no longer deprecates
these instruction uses.

Also Armv8 manuals no longer consider SP as deprecated register for ldm/
stm A32 instructions.

Furthermore, GNU as also does not print a deprecated warning when using
SP with those instructions.

Drop deprecation warning for pop/ldm/push/stm instructions.

Diff Detail

Event Timeline

falstaff84 created this revision.Jun 26 2020, 4:43 PM
Herald added a project: Restricted Project. · View Herald TranscriptJun 26 2020, 4:43 PM
Herald added subscribers: llvm-commits, danielkiss, hiraditya, kristof.beyls. · View Herald Transcript
Harbormaster failed remote builds in B62006: Diff 273863!Jun 26 2020, 5:44 PM
SjoerdMeijer accepted this revision.Jul 29 2020, 8:59 AM
SjoerdMeijer added a subscriber: SjoerdMeijer.

Yep, agree, LGTM

This revision is now accepted and ready to land.Jul 29 2020, 8:59 AM
nickdesaulniers added a comment.Oct 29 2020, 2:00 PM

bumping; was this waiting on anything?

nickdesaulniers added a comment.Feb 22 2021, 3:28 PM

@SjoerdMeijer can you please commit this? I don't think @falstaff84 has commit access.

This revision was landed with ongoing or failed builds.Feb 23 2021, 5:27 AM
Closed by commit rGe1c3bf6afe09: [ARM] do not consider sp as deprecated for ldm/stm (authored by SjoerdMeijer). · Explain Why
This revision was automatically updated to reflect the committed changes.
SjoerdMeijer added a commit: rGe1c3bf6afe09: [ARM] do not consider sp as deprecated for ldm/stm.
SjoerdMeijer added a comment.Feb 23 2021, 5:30 AM

Sorry missed the earlier message, but this has now been committed.

Revision Contents

PathSize
llvm/
lib/
Target/
ARM/
MCTargetDesc/
8 lines
test/
CodeGen/
ARM/
2 lines
MC/
ARM/
156 lines

Diff 325750

llvm/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp

Show First 20 Lines • Show All 101 Lines • ▼ Show 20 Lines
static bool getARMStoreDeprecationInfo(MCInst &MI, const MCSubtargetInfo &STI, static bool getARMStoreDeprecationInfo(MCInst &MI, const MCSubtargetInfo &STI,
std::string &Info) { std::string &Info) {
assert(!STI.getFeatureBits()[llvm::ARM::ModeThumb] && assert(!STI.getFeatureBits()[llvm::ARM::ModeThumb] &&
"cannot predicate thumb instructions"); "cannot predicate thumb instructions");
assert(MI.getNumOperands() >= 4 && "expected >= 4 arguments"); assert(MI.getNumOperands() >= 4 && "expected >= 4 arguments");
for (unsigned OI = 4, OE = MI.getNumOperands(); OI < OE; ++OI) { for (unsigned OI = 4, OE = MI.getNumOperands(); OI < OE; ++OI) {
assert(MI.getOperand(OI).isReg() && "expected register"); assert(MI.getOperand(OI).isReg() && "expected register");
if (MI.getOperand(OI).getReg() == ARM::SP || if (MI.getOperand(OI).getReg() == ARM::PC) {
MI.getOperand(OI).getReg() == ARM::PC) { Info = "use of PC in the list is deprecated";
Info = "use of SP or PC in the list is deprecated";
return true; return true;
} }
} }
return false; return false;
} }
static bool getARMLoadDeprecationInfo(MCInst &MI, const MCSubtargetInfo &STI, static bool getARMLoadDeprecationInfo(MCInst &MI, const MCSubtargetInfo &STI,
std::string &Info) { std::string &Info) {
assert(!STI.getFeatureBits()[llvm::ARM::ModeThumb] && assert(!STI.getFeatureBits()[llvm::ARM::ModeThumb] &&
"cannot predicate thumb instructions"); "cannot predicate thumb instructions");
assert(MI.getNumOperands() >= 4 && "expected >= 4 arguments"); assert(MI.getNumOperands() >= 4 && "expected >= 4 arguments");
bool ListContainsPC = false, ListContainsLR = false; bool ListContainsPC = false, ListContainsLR = false;
for (unsigned OI = 4, OE = MI.getNumOperands(); OI < OE; ++OI) { for (unsigned OI = 4, OE = MI.getNumOperands(); OI < OE; ++OI) {
assert(MI.getOperand(OI).isReg() && "expected register"); assert(MI.getOperand(OI).isReg() && "expected register");
switch (MI.getOperand(OI).getReg()) { switch (MI.getOperand(OI).getReg()) {
default: default:
break; break;
case ARM::LR: case ARM::LR:
ListContainsLR = true; ListContainsLR = true;
break; break;
case ARM::PC: case ARM::PC:
ListContainsPC = true; ListContainsPC = true;
break; break;
case ARM::SP:
Info = "use of SP in the list is deprecated";
return true;
} }
} }
if (ListContainsPC && ListContainsLR) { if (ListContainsPC && ListContainsLR) {
Info = "use of LR and PC simultaneously in the list is deprecated"; Info = "use of LR and PC simultaneously in the list is deprecated";
return true; return true;
} }
▲ Show 20 Lines • Show All 390 Lines • Show Last 20 Lines

llvm/test/CodeGen/ARM/deprecated-asm.s

// REQUIRES: asserts // REQUIRES: asserts
// RUN: llvm-mc < %s -triple=armv4t-linux-gnueabi -filetype=obj -o %t.o -no-deprecated-warn -stats 2>&1 | FileCheck %s // RUN: llvm-mc < %s -triple=armv4t-linux-gnueabi -filetype=obj -o %t.o -no-deprecated-warn -stats 2>&1 | FileCheck %s
// RUN: llvm-mc < %s -triple=armv4t-linux-gnueabi -filetype=obj -o %t.o 2>&1 | FileCheck %s -check-prefix=WARN // RUN: llvm-mc < %s -triple=armv4t-linux-gnueabi -filetype=obj -o %t.o -stats 2>&1 | FileCheck %s
.text .text
.syntax unified .syntax unified
.eabi_attribute 67, "2.09" @ Tag_conformance .eabi_attribute 67, "2.09" @ Tag_conformance
.cpu arm7tdmi .cpu arm7tdmi
.eabi_attribute 6, 2 @ Tag_CPU_arch .eabi_attribute 6, 2 @ Tag_CPU_arch
.eabi_attribute 8, 1 @ Tag_ARM_ISA_use .eabi_attribute 8, 1 @ Tag_ARM_ISA_use
.eabi_attribute 17, 1 @ Tag_ABI_PCS_GOT_use .eabi_attribute 17, 1 @ Tag_ABI_PCS_GOT_use
Show All 32 Lines

llvm/test/MC/ARM/arm-load-store-multiple-deprecated.s

@ RUN: llvm-mc -triple armv6t2-linux-eabi -filetype asm -o - %s 2>&1 \ @ RUN: llvm-mc -triple armv6t2-linux-eabi -filetype asm -o - %s 2>&1 \
@ RUN: | FileCheck %s @ RUN: | FileCheck %s
@ RUN: not llvm-mc -triple armv6t2-linux-eabi --fatal-warnings -filetype asm -o - %s 2>&1 \ @ RUN: not llvm-mc -triple armv6t2-linux-eabi --fatal-warnings -filetype asm -o - %s 2>&1 \
@ RUN: | FileCheck -check-prefix CHECK-ERROR %s @ RUN: | FileCheck -check-prefix CHECK-ERROR %s
@ RUN: not llvm-mc -triple armv7-linux-eabi -filetype asm -o - %s 2>&1 \ @ RUN: not llvm-mc -triple armv7-linux-eabi -filetype asm -o - %s 2>&1 \
@ RUN: | FileCheck %s -check-prefix CHECK -check-prefix CHECK-V7 @ RUN: | FileCheck %s -check-prefix CHECK -check-prefix CHECK-V7
@ RUN: not llvm-mc -triple armv8-linux-eabi -filetype asm -o - %s 2>&1 \
@ RUN: | FileCheck %s -check-prefix CHECK -check-prefix CHECK-V7
.syntax unified .syntax unified
.arm .arm
.global stm .global stm
.type stm,%function .type stm,%function
stm: stm:
stm sp!, {r0, pc} stm sp!, {r0, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK-ERROR: error: use of SP or PC in the list is deprecated @ CHECK-ERROR: error: use of PC in the list is deprecated
@ CHECK: stm sp!, {r0, pc} @ CHECK: stm sp!, {r0, pc}
@ CHECK: ^ @ CHECK: ^
stm r0!, {r0, sp}
@ CHECK: warning: use of SP or PC in the list is deprecated
@ CHECK-ERROR: error: use of SP or PC in the list is deprecated
@ CHECK: stm r0!, {r0, sp}
@ CHECK: ^
stm r1!, {r0, sp, pc} stm r1!, {r0, sp, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stm r1!, {r0, sp, pc} @ CHECK: stm r1!, {r0, sp, pc}
@ CHECK: ^ @ CHECK: ^
stm r2!, {sp, pc} stm r2!, {sp, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stm r2!, {sp, pc} @ CHECK: stm r2!, {sp, pc}
@ CHECK: ^ @ CHECK: ^
stm sp!, {pc} stm sp!, {pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stm sp!, {pc} @ CHECK: stm sp!, {pc}
@ CHECK: ^ @ CHECK: ^
stm r0!, {sp}
@ CHECK: warning: use of SP or PC in the list is deprecated
@ CHECK: stm r0!, {sp}
@ CHECK: ^
.global stmda .global stmda
.type stmda,%function .type stmda,%function
stmda: stmda:
stmda sp!, {r0, pc} stmda sp!, {r0, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stmda sp!, {r0, pc} @ CHECK: stmda sp!, {r0, pc}
@ CHECK: ^ @ CHECK: ^
stmda r0!, {r0, sp}
@ CHECK: warning: use of SP or PC in the list is deprecated
@ CHECK: stmda r0!, {r0, sp}
@ CHECK: ^
stmda r1!, {r0, sp, pc} stmda r1!, {r0, sp, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stmda r1!, {r0, sp, pc} @ CHECK: stmda r1!, {r0, sp, pc}
@ CHECK: ^ @ CHECK: ^
stmda r2!, {sp, pc} stmda r2!, {sp, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stmda r2!, {sp, pc} @ CHECK: stmda r2!, {sp, pc}
@ CHECK: ^ @ CHECK: ^
stmda sp!, {pc} stmda sp!, {pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stmda sp!, {pc} @ CHECK: stmda sp!, {pc}
@ CHECK: ^ @ CHECK: ^
stmda r0!, {sp}
@ CHECK: warning: use of SP or PC in the list is deprecated
@ CHECK: stmda r0!, {sp}
@ CHECK: ^
.global stmdb .global stmdb
.type stmdb,%function .type stmdb,%function
stmdb: stmdb:
stmdb sp!, {r0, pc} stmdb sp!, {r0, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stmdb sp!, {r0, pc} @ CHECK: stmdb sp!, {r0, pc}
@ CHECK: ^ @ CHECK: ^
stmdb r0!, {r0, sp}
@ CHECK: warning: use of SP or PC in the list is deprecated
@ CHECK: stmdb r0!, {r0, sp}
@ CHECK: ^
stmdb r1!, {r0, sp, pc} stmdb r1!, {r0, sp, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stmdb r1!, {r0, sp, pc} @ CHECK: stmdb r1!, {r0, sp, pc}
@ CHECK: ^ @ CHECK: ^
stmdb r2!, {sp, pc} stmdb r2!, {sp, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stmdb r2!, {sp, pc} @ CHECK: stmdb r2!, {sp, pc}
@ CHECK: ^ @ CHECK: ^
stmdb sp!, {pc} stmdb sp!, {pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stmdb sp!, {pc} @ CHECK: stmdb sp!, {pc}
@ CHECK: ^ @ CHECK: ^
stmdb r0!, {sp}
@ CHECK: warning: use of SP or PC in the list is deprecated
@ CHECK: stmdb r0!, {sp}
@ CHECK: ^
.global stmib .global stmib
.type stmib,%function .type stmib,%function
stmib: stmib:
stmib sp!, {r0, pc} stmib sp!, {r0, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stmib sp!, {r0, pc} @ CHECK: stmib sp!, {r0, pc}
@ CHECK: ^ @ CHECK: ^
stmib r0!, {r0, sp}
@ CHECK: warning: use of SP or PC in the list is deprecated
@ CHECK: stmib r0!, {r0, sp}
@ CHECK: ^
stmib r1!, {r0, sp, pc} stmib r1!, {r0, sp, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stmib r1!, {r0, sp, pc} @ CHECK: stmib r1!, {r0, sp, pc}
@ CHECK: ^ @ CHECK: ^
stmib r2!, {sp, pc} stmib r2!, {sp, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stmib r2!, {sp, pc} @ CHECK: stmib r2!, {sp, pc}
@ CHECK: ^ @ CHECK: ^
stmib sp!, {pc} stmib sp!, {pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: stmib sp!, {pc} @ CHECK: stmib sp!, {pc}
@ CHECK: ^ @ CHECK: ^
stmib r0!, {sp}
@ CHECK: warning: use of SP or PC in the list is deprecated
@ CHECK: stmib r0!, {sp}
@ CHECK: ^
.global push .global push
.type push,%function .type push,%function
push: push:
push {r0, pc} push {r0, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: push {r0, pc} @ CHECK: push {r0, pc}
@ CHECK: ^ @ CHECK: ^
push {r0, sp}
@ CHECK: warning: use of SP or PC in the list is deprecated
@ CHECK: push {r0, sp}
@ CHECK: ^
push {r0, sp, pc} push {r0, sp, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: push {r0, sp, pc} @ CHECK: push {r0, sp, pc}
@ CHECK: ^ @ CHECK: ^
push {sp, pc} push {sp, pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: push {sp, pc} @ CHECK: push {sp, pc}
@ CHECK: ^ @ CHECK: ^
push {pc} push {pc}
@ CHECK: warning: use of SP or PC in the list is deprecated @ CHECK: warning: use of PC in the list is deprecated
@ CHECK: push {pc} @ CHECK: push {pc}
@ CHECK: ^ @ CHECK: ^
push {sp}
@ CHECK: warning: use of SP or PC in the list is deprecated
@ CHECK: push {sp}
@ CHECK: ^
.global ldm .global ldm
.type ldm,%function .type ldm,%function
ldm: ldm:
ldm r0!, {r1, sp}
@ CHECK: warning: use of SP in the list is deprecated
ldm r0!, {sp}
@ CHECK: warning: use of SP in the list is deprecated
ldm r0!, {r1, lr, pc} ldm r0!, {r1, lr, pc}
@ CHECK: warning: use of LR and PC simultaneously in the list is deprecated @ CHECK: warning: use of LR and PC simultaneously in the list is deprecated
ldm r0!, {lr, pc} ldm r0!, {lr, pc}
@ CHECK: warning: use of LR and PC simultaneously in the list is deprecated @ CHECK: warning: use of LR and PC simultaneously in the list is deprecated
.global ldmda .global ldmda
.type ldmda,%function .type ldmda,%function
ldmda: ldmda:
ldmda r0!, {r1, sp}
@ CHECK: warning: use of SP in the list is deprecated
ldmda r0!, {sp}
@ CHECK: warning: use of SP in the list is deprecated
ldmda r0!, {r1, lr, pc} ldmda r0!, {r1, lr, pc}
@ CHECK: warning: use of LR and PC simultaneously in the list is deprecated @ CHECK: warning: use of LR and PC simultaneously in the list is deprecated
ldmda r0!, {lr, pc} ldmda r0!, {lr, pc}
@ CHECK: warning: use of LR and PC simultaneously in the list is deprecated @ CHECK: warning: use of LR and PC simultaneously in the list is deprecated
.global ldmdb .global ldmdb
.type ldmdb,%function .type ldmdb,%function
ldmdb: ldmdb:
ldmdb r0!, {r1, sp}
@ CHECK: warning: use of SP in the list is deprecated
ldmdb r0!, {sp}
@ CHECK: warning: use of SP in the list is deprecated
ldmdb r0!, {r1, lr, pc} ldmdb r0!, {r1, lr, pc}
@ CHECK: warning: use of LR and PC simultaneously in the list is deprecated @ CHECK: warning: use of LR and PC simultaneously in the list is deprecated
ldmdb r0!, {lr, pc} ldmdb r0!, {lr, pc}
@ CHECK: warning: use of LR and PC simultaneously in the list is deprecated @ CHECK: warning: use of LR and PC simultaneously in the list is deprecated
.global ldmib .global ldmib
.type ldmib,%function .type ldmib,%function
ldmib: ldmib:
ldmib r0!, {r1, sp}
@ CHECK: warning: use of SP in the list is deprecated
ldmib r0!, {sp}
@ CHECK: warning: use of SP in the list is deprecated
ldmib r0!, {r1, lr, pc} ldmib r0!, {r1, lr, pc}
@ CHECK: warning: use of LR and PC simultaneously in the list is deprecated @ CHECK: warning: use of LR and PC simultaneously in the list is deprecated
ldmib r0!, {lr, pc} ldmib r0!, {lr, pc}
@ CHECK: warning: use of LR and PC simultaneously in the list is deprecated @ CHECK: warning: use of LR and PC simultaneously in the list is deprecated
.global pop .global pop
.type pop,%function .type pop,%function
pop: pop:
pop {r0, sp} pop {r0, sp}
@ CHECK: warning: use of SP in the list is deprecated
@ CHECK-V7: error: writeback register not allowed in register list @ CHECK-V7: error: writeback register not allowed in register list
pop {sp} pop {sp}
@ CHECK: warning: use of SP in the list is deprecated
@ CHECK-V7: error: writeback register not allowed in register list @ CHECK-V7: error: writeback register not allowed in register list
pop {r0, lr, pc} pop {r0, lr, pc}
@ CHECK: warning: use of LR and PC simultaneously in the list is deprecated @ CHECK: warning: use of LR and PC simultaneously in the list is deprecated
pop {lr, pc} pop {lr, pc}
@ CHECK: warning: use of LR and PC simultaneously in the list is deprecated @ CHECK: warning: use of LR and PC simultaneously in the list is deprecated
.global valid .global valid_stm
.type valid,%function .type valid,%function
valid: valid_stm:
stm r0!, {r0, sp}
@ CHECK: stm r0!, {r0, sp}
stm r0!, {sp}
@ CHECK: stm r0!, {sp}
stmda r0!, {r0, sp}
@ CHECK: stmda r0!, {r0, sp}
stmda r0!, {sp}
@ CHECK: stmda r0!, {sp}
stmdb r0!, {r0, sp}
@ CHECK: stmdb r0!, {r0, sp}
stmdb r0!, {sp}
@ CHECK: stmdb r0!, {sp}
stmib r0!, {r0, sp}
@ CHECK: stmib r0!, {r0, sp}
stmib r0!, {sp}
@ CHECK: stmib r0!, {sp}
stmdaeq r0, {r0} stmdaeq r0, {r0}
@ CHECK: stmdaeq r0, {r0} @ CHECK: stmdaeq r0, {r0}
.global valid_push
.type valid,%function
valid_push:
push {r0, sp}
@ CHECK: push {r0, sp}
push {sp}
@ CHECK: push {sp}
.global valid_ldm
.type valid,%function
valid_ldm:
ldm r0!, {r1, sp}
@ CHECK: ldm r0!, {r1, sp}
ldm r0!, {sp}
@ CHECK: ldm r0!, {sp}
ldmda r0!, {r1, sp}
@ CHECK: ldmda r0!, {r1, sp}
ldmda r0!, {sp}
@ CHECK: ldmda r0!, {sp}
ldmdb r0!, {r1, sp}
@ CHECK: ldmdb r0!, {r1, sp}
ldmdb r0!, {sp}
@ CHECK: ldmdb r0!, {sp}
ldmib r0!, {r1, sp}
@ CHECK: ldmib r0!, {r1, sp}
ldmib r0!, {sp}
@ CHECK: ldmib r0!, {sp}
ldmdaeq r0, {r0} ldmdaeq r0, {r0}
@ CHECK: ldmdaeq r0, {r0} @ CHECK: ldmdaeq r0, {r0}
.global valid_pop
.type valid,%function
valid_pop:
pop {r0, pc} pop {r0, pc}
@ CHECK: pop {r0, pc} @ CHECK: pop {r0, pc}