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[MIPS] Don't emit R_(MICRO)MIPS_JALR relocations against data symbols 

The R_(MICRO)MIPS_JALR optimization only works when used against functions.
Using the relocation against a data symbol (e.g. function pointer) will
cause some linkers that don't ignore the hint in this case (e.g. LLD prior
to commit 5bab291b7b) to generate a relative branch to the data symbol
which crashes at run time. Before this patch, LLVM was erroneously emitting
these relocations against local-dynamic TLS function pointers and global
function pointers with internal visibility.

Reviewers: atanasyan, jrtc27, vstefanovic
Reviewed By: atanasyan
Differential Revision: https://reviews.llvm.org/D72571
This commit is contained in:
Alex Richardson 2020-01-13 13:52:48 +00:00
parent 894f742acb
commit 8e8ccf4712
2 changed files with 104 additions and 58 deletions
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9
llvm/lib/Target/Mips/MipsISelLowering.cpp
View File

@ -3111,6 +3111,14 @@ void MipsTargetLowering::AdjustInstrPostInstrSelection(MachineInstr &MI,
StringRef Sym;
if (const GlobalAddressSDNode *G =
dyn_cast_or_null<const GlobalAddressSDNode>(TargetAddr)) {
// We must not emit the R_MIPS_JALR relocation against data symbols
// since this will cause run-time crashes if the linker replaces the
// call instruction with a relative branch to the data symbol.
if (!isa<Function>(G->getGlobal())) {
LLVM_DEBUG(dbgs() << "Not adding R_MIPS_JALR against data symbol "
<< G->getGlobal()->getName() << "\n");
return;
}
Sym = G->getGlobal()->getName();
}
else if (const ExternalSymbolSDNode *ES =
@ -3123,6 +3131,7 @@ void MipsTargetLowering::AdjustInstrPostInstrSelection(MachineInstr &MI,
MachineFunction *MF = MI.getParent()->getParent();
MCSymbol *S = MF->getContext().getOrCreateSymbol(Sym);
LLVM_DEBUG(dbgs() << "Adding R_MIPS_JALR against " << Sym << "\n");
MI.addOperand(MachineOperand::CreateMCSymbol(S, MipsII::MO_JALR));
}
}

153
llvm/test/CodeGen/Mips/reloc-jalr.ll
View File

@ -1,64 +1,64 @@
; RUN: llc -mtriple=mips-linux-gnu -relocation-model=pic -mips-tail-calls=1 \
; RUN: -O2 < %s | \
; RUN: FileCheck %s -check-prefixes=ALL,JALR-32R2,TAILCALL-32R2
; RUN: FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-32,JALR-32R2,TAILCALL-32R2
; RUN: llc -mtriple=mips64-linux-gnu -relocation-model=pic -mips-tail-calls=1 \
; RUN: -O2 < %s | \
; RUN: FileCheck %s -check-prefixes=ALL,JALR-64R2,TAILCALL-64R2
; RUN: FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-64,JALR-64R2,TAILCALL-64R2
; RUN: llc -mtriple=mips-linux-gnu -relocation-model=pic -mips-tail-calls=1 \
; RUN: -O2 -mcpu=mips32r6 -mips-compact-branches=always < %s | \
; RUN: FileCheck %s -check-prefixes=ALL,JALR-32R6,TAILCALL-32R6
; RUN: FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-32,JALR-32R6,TAILCALL-32R6
; RUN: llc -mtriple=mips64-linux-gnu -relocation-model=pic -mips-tail-calls=1 \
; RUN: -O2 -mcpu=mips64r6 -mips-compact-branches=always < %s | \
; RUN: FileCheck %s -check-prefixes=ALL,JALR-64R6,TAILCALL-64R6
; RUN: FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-64,JALR-64R6,TAILCALL-64R6
; RUN: llc -mtriple=mips-linux-gnu -relocation-model=pic -mips-tail-calls=1 \
; RUN: -O2 -mcpu=mips32r6 -mips-compact-branches=never < %s | \
; RUN: FileCheck %s -check-prefixes=ALL,JALR-32R2,TAILCALL-32R2
; RUN: FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-32,JALR-32R2,TAILCALL-32R2
; RUN: llc -mtriple=mips64-linux-gnu -relocation-model=pic -mips-tail-calls=1 \
; RUN: -O2 -mcpu=mips64r6 -mips-compact-branches=never < %s | \
; RUN: FileCheck %s -check-prefixes=ALL,JALR-64R2,TAILCALL-64R2
; RUN: FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-64,JALR-64R2,TAILCALL-64R2
; RUN: llc -mtriple=mips-linux-gnu -relocation-model=pic -mips-tail-calls=1 \
; RUN: -O2 -mattr=+micromips -mcpu=mips32r2 < %s | \
; RUN: FileCheck %s -check-prefixes=ALL,JALR-MM,TAILCALL-MM
; RUN: FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-MM,TAILCALL-MM
; RUN: llc -mtriple=mips-linux-gnu -relocation-model=pic -mips-tail-calls=1 \
; RUN: -O2 -mattr=+micromips -mcpu=mips32r6 < %s | \
; RUN: FileCheck %s -check-prefixes=ALL,JALR-MM
; RUN: FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-MM,TAILCALL-MM
; RUN: llc -mtriple=mips-linux-gnu -relocation-model=pic \
; RUN: -O0 < %s | FileCheck %s -check-prefixes=ALL,JALR-32R2
; RUN: -O0 < %s | FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-32,JALR-32R2,PIC-NOTAILCALL-R2
; RUN: llc -mtriple=mips64-linux-gnu -relocation-model=pic \
; RUN: -O0 < %s | FileCheck %s -check-prefixes=ALL,JALR-64R2
; RUN: -O0 < %s | FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-64,JALR-64R2,PIC-NOTAILCALL-R2
; RUN: llc -mtriple=mips-linux-gnu -relocation-model=pic \
; RUN: -O0 -mcpu=mips32r6 -mips-compact-branches=always < %s | \
; RUN: FileCheck %s -check-prefixes=ALL,JALR-32R6
; RUN: FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-32,JALR-32R6,PIC-NOTAILCALL-R6
; RUN: llc -mtriple=mips64-linux-gnu -relocation-model=pic \
; RUN: -O0 -mcpu=mips64r6 -mips-compact-branches=always < %s | \
; RUN: FileCheck %s -check-prefixes=ALL,JALR-64R6
; RUN: FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-64,JALR-64R6,PIC-NOTAILCALL-R6
; RUN: llc -mtriple=mips-linux-gnu -relocation-model=pic \
; RUN: -O0 -mcpu=mips32r6 -mips-compact-branches=never < %s | \
; RUN: FileCheck %s -check-prefixes=ALL,JALR-32R2
; RUN: FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-32,JALR-32R2,PIC-NOTAILCALL-R2
; RUN: llc -mtriple=mips64-linux-gnu -relocation-model=pic \
; RUN: -O0 -mcpu=mips64r6 -mips-compact-branches=never < %s | \
; RUN: FileCheck %s -check-prefixes=ALL,JALR-64R2
; RUN: FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-64,JALR-64R2,PIC-NOTAILCALL-R2
; RUN: llc -mtriple=mips-linux-gnu -relocation-model=pic \
; RUN: -O0 -mattr=+micromips -mcpu=mips32r2 < %s | \
; RUN: FileCheck %s -check-prefixes=ALL,JALR-MM
; RUN: FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-MM,PIC-NOTAILCALL-MM
; RUN: llc -mtriple=mips-linux-gnu -relocation-model=pic \
; RUN: -O0 -mattr=+micromips -mcpu=mips32r6 < %s | \
; RUN: FileCheck %s -check-prefixes=ALL,JALR-MM
; RUN: FileCheck %s -check-prefixes=ALL,JALR-ALL,JALR-MM,PIC-NOTAILCALL-MM
; RUN: llc -mtriple=mips-linux-gnu -relocation-model=pic -mips-tail-calls=1 \
; RUN: -O2 -mips-jalr-reloc=false < %s | \
@ -100,55 +100,92 @@ entry:
define void @checkCall() {
entry:
; ALL-LABEL: checkCall:
; ALL-NOT: MIPS_JALR
call void @foo()
; JALR-32R2: .reloc ([[TMPLABEL:.*]]), R_MIPS_JALR, foo
; JALR-32R2-NEXT: [[TMPLABEL]]:
; JALR-32R2-NEXT: jalr $25
; JALR-64R2: .reloc [[TMPLABEL:.*]], R_MIPS_JALR, foo
; JALR-64R2-NEXT: [[TMPLABEL]]:
; JALR-64R2-NEXT: jalr $25
; JALR-MM: .reloc ([[TMPLABEL:.*]]), R_MICROMIPS_JALR, foo
; JALR-MM-NEXT: [[TMPLABEL]]:
; JALR-MM-NEXT: jalr $25
; JALR-32R6: .reloc ([[TMPLABEL:.*]]), R_MIPS_JALR, foo
; JALR-32R6-NEXT: [[TMPLABEL]]:
; JALR-32R6-NEXT: jalrc $25
; JALR-64R6: .reloc [[TMPLABEL:.*]], R_MIPS_JALR, foo
; JALR-64R6-NEXT: [[TMPLABEL]]:
; JALR-64R6-NEXT: jalrc $25
; NORELOC-NOT: R_MIPS_JALR
; JALR-32: .reloc ([[TMPLABEL:\$.+]]), R_MIPS_JALR, foo
; JALR-64: .reloc [[TMPLABEL:\..+]], R_MIPS_JALR, foo
; JALR-MM: .reloc ([[TMPLABEL:\$.+]]), R_MICROMIPS_JALR, foo
; JALR-ALL-NEXT: [[TMPLABEL]]:
; JALR-32R2-NEXT: jalr $25
; JALR-64R2-NEXT: jalr $25
; JALR-32R6-NEXT: jalrc $25
; JALR-64R6-NEXT: jalrc $25
; JALR-MM-NEXT: jalr $25
; ALL-NOT: MIPS_JALR
ret void
}
define void @checkTailCall() {
entry:
; ALL-LABEL: checkTailCall:
; ALL-NOT: MIPS_JALR
tail call void @foo()
; TAILCALL-32R2: .reloc ([[TMPLABEL:.*]]), R_MIPS_JALR, foo
; TAILCALL-32R2-NEXT: [[TMPLABEL]]:
; TAILCALL-32R2-NEXT: jr $25
; TAILCALL-64R2: .reloc [[TMPLABEL:.*]], R_MIPS_JALR, foo
; TAILCALL-64R2-NEXT: [[TMPLABEL]]:
; TAILCALL-64R2-NEXT: jr $25
; TAILCALL-MM: .reloc ([[TMPLABEL:.*]]), R_MICROMIPS_JALR, foo
; TAILCALL-MM-NEXT: [[TMPLABEL]]:
; TAILCALL-MM-NEXT: jrc $25
; TAILCALL-32R6: .reloc ([[TMPLABEL:.*]]), R_MIPS_JALR, foo
; TAILCALL-32R6-NEXT: [[TMPLABEL]]:
; TAILCALL-32R6-NEXT: jrc $25
; TAILCALL-64R6: .reloc [[TMPLABEL:.*]], R_MIPS_JALR, foo
; TAILCALL-64R6-NEXT: [[TMPLABEL]]:
; TAILCALL-64R6-NEXT: jrc $25
; NORELOC-NOT: R_MIPS_JALR
; JALR-32: .reloc ([[TMPLABEL:\$.+]]), R_MIPS_JALR, foo
; JALR-64: .reloc [[TMPLABEL:\..+]], R_MIPS_JALR, foo
; JALR-MM: .reloc ([[TMPLABEL:\$.+]]), R_MICROMIPS_JALR, foo
; JALR-ALL-NEXT: [[TMPLABEL]]:
; TAILCALL-32R2-NEXT: jr $25
; TAILCALL-64R2-NEXT: jr $25
; TAILCALL-MM-NEXT: jrc $25
; TAILCALL-32R6-NEXT: jrc $25
; TAILCALL-64R6-NEXT: jrc $25
; PIC-NOTAILCALL-R2-NEXT: jalr $25
; PIC-NOTAILCALL-R6-NEXT: jalrc $25
; PIC-NOTAILCALL-MM-NEXT: jalr $25
; ALL-NOT: MIPS_JALR
ret void
}
; Check that we don't emit R_MIPS_JALR relocations against function pointers.
; This resulted in run-time crashes until lld was modified to ignore
; R_MIPS_JALR relocations against data symbols (commit 5bab291b7b).
; However, the better approach is to not emit these relocations in the first
; place so check that we no longer emit them.
; Previously we were adding them for local dynamic TLS function pointers and
; function pointers with internal linkage.
@fnptr_internal = internal global void()* @checkFunctionPointerCall
@fnptr_internal_const = internal constant void()* @checkFunctionPointerCall
@fnptr_const = constant void()* @checkFunctionPointerCall
@fnptr_global = global void()* @checkFunctionPointerCall
define void @checkFunctionPointerCall() {
entry:
; ALL-LABEL: checkFunctionPointerCall:
; ALL-NOT: MIPS_JALR
%func_internal = load void()*, void()** @fnptr_internal
call void %func_internal()
%func_internal_const = load void()*, void()** @fnptr_internal_const
call void %func_internal_const()
%func_const = load void()*, void()** @fnptr_const
call void %func_const()
%func_global = load void()*, void()** @fnptr_global
call void %func_global()
ret void
}
@tls_fnptr_gd = thread_local global void()* @checkTlsFunctionPointerCall
@tls_fnptr_ld = thread_local(localdynamic) global void()* @checkTlsFunctionPointerCall
@tls_fnptr_ie = thread_local(initialexec) global void()* @checkTlsFunctionPointerCall
@tls_fnptr_le = thread_local(localexec) global void()* @checkTlsFunctionPointerCall
define void @checkTlsFunctionPointerCall() {
entry:
; There should not be any *JALR relocations in this function other than the
; calls to __tls_get_addr:
; ALL-LABEL: checkTlsFunctionPointerCall:
; ALL-NOT: MIPS_JALR
; JALR-ALL: .reloc {{.+}}MIPS_JALR, __tls_get_addr
; ALL-NOT: MIPS_JALR
; JALR-ALL: .reloc {{.+}}MIPS_JALR, __tls_get_addr
; ALL-NOT: _MIPS_JALR
%func_gd = load void()*, void()** @tls_fnptr_gd
call void %func_gd()
%func_ld = load void()*, void()** @tls_fnptr_ld
call void %func_ld()
%func_ie = load void()*, void()** @tls_fnptr_ie
call void %func_ie()
%func_le = load void()*, void()** @tls_fnptr_le
call void %func_le()
ret void
}