[llvm] 8e8ccf4 - [MIPS] Don't emit R_(MICRO)MIPS_JALR relocations against data symbols
Alex Richardson via llvm-commits
llvm-commits at lists.llvm.org
Mon Jan 13 06:14:24 PST 2020
Author: Alex Richardson
Date: 2020-01-13T14:14:03Z
New Revision: 8e8ccf4712cf58562a91c197da3efd4f9963ce0d
URL: https://github.com/llvm/llvm-project/commit/8e8ccf4712cf58562a91c197da3efd4f9963ce0d
DIFF: https://github.com/llvm/llvm-project/commit/8e8ccf4712cf58562a91c197da3efd4f9963ce0d.diff
LOG: [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
Added:
Modified:
llvm/lib/Target/Mips/MipsISelLowering.cpp
llvm/test/CodeGen/Mips/reloc-jalr.ll
Removed:
################################################################################
diff --git a/llvm/lib/Target/Mips/MipsISelLowering.cpp b/llvm/lib/Target/Mips/MipsISelLowering.cpp
index ea242b4d46b8..46b1f35a6fc7 100644
--- a/llvm/lib/Target/Mips/MipsISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsISelLowering.cpp
@@ -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));
}
}
diff --git a/llvm/test/CodeGen/Mips/reloc-jalr.ll b/llvm/test/CodeGen/Mips/reloc-jalr.ll
index f8fd90311004..ef360266a1bb 100644
--- a/llvm/test/CodeGen/Mips/reloc-jalr.ll
+++ b/llvm/test/CodeGen/Mips/reloc-jalr.ll
@@ -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
+; 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
+}
-; TAILCALL-64R2: .reloc [[TMPLABEL:.*]], R_MIPS_JALR, foo
-; TAILCALL-64R2-NEXT: [[TMPLABEL]]:
-; TAILCALL-64R2-NEXT: jr $25
+; 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.
-; TAILCALL-MM: .reloc ([[TMPLABEL:.*]]), R_MICROMIPS_JALR, foo
-; TAILCALL-MM-NEXT: [[TMPLABEL]]:
-; TAILCALL-MM-NEXT: jrc $25
+ at fnptr_internal = internal global void()* @checkFunctionPointerCall
+ at fnptr_internal_const = internal constant void()* @checkFunctionPointerCall
+ at fnptr_const = constant void()* @checkFunctionPointerCall
+ at fnptr_global = global void()* @checkFunctionPointerCall
-; TAILCALL-32R6: .reloc ([[TMPLABEL:.*]]), R_MIPS_JALR, foo
-; TAILCALL-32R6-NEXT: [[TMPLABEL]]:
-; TAILCALL-32R6-NEXT: jrc $25
+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
+}
-; TAILCALL-64R6: .reloc [[TMPLABEL:.*]], R_MIPS_JALR, foo
-; TAILCALL-64R6-NEXT: [[TMPLABEL]]:
-; TAILCALL-64R6-NEXT: jrc $25
+ at tls_fnptr_gd = thread_local global void()* @checkTlsFunctionPointerCall
+ at tls_fnptr_ld = thread_local(localdynamic) global void()* @checkTlsFunctionPointerCall
+ at tls_fnptr_ie = thread_local(initialexec) global void()* @checkTlsFunctionPointerCall
+ at tls_fnptr_le = thread_local(localexec) global void()* @checkTlsFunctionPointerCall
-; NORELOC-NOT: R_MIPS_JALR
+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
}
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