[llvm-branch-commits] [llvm] 981b225 - [AArch64] Allow PAC mnemonics in the HINT space with PAC disabled
Pablo Barrio via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Fri Apr 24 08:52:26 PDT 2020
Author: Pablo Barrio
Date: 2020-04-24T16:50:42+01:00
New Revision: 981b2258ebdc27001405d333015e12297dd536f5
URL: https://github.com/llvm/llvm-project/commit/981b2258ebdc27001405d333015e12297dd536f5
DIFF: https://github.com/llvm/llvm-project/commit/981b2258ebdc27001405d333015e12297dd536f5.diff
LOG: [AArch64] Allow PAC mnemonics in the HINT space with PAC disabled
Summary:
It is important to emit HINT instructions instead of PAC ones when
PAC is disabled. This allows compatibility with other assemblers
(e.g. GAS). This was implemented in commit da33762de853.
Still, developers of assembly code will want to write code that is
compatible with both pre- and post-PAC CPUs. They could use HINT
mnemonics, but the new mnemonics are a lot more readable (e.g.
paciaz instead of hint #24), and they will result in the same
encodings. So, while LLVM should not *emit* the new mnemonics when
PAC is disabled, this patch will at least make LLVM *accept*
assembly code that uses them.
Reviewers: danielkiss, chill, olista01, LukeCheeseman, simon_tatham
Subscribers: kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D78372
Added:
Modified:
llvm/lib/Target/AArch64/AArch64InstrInfo.td
llvm/test/MC/AArch64/armv8.3a-signed-pointer.s
Removed:
################################################################################
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 91af6c79a427..913e23c861da 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -915,10 +915,28 @@ let Uses = [LR], Defs = [LR], CRm = 0b0000 in {
def XPACLRI : SystemNoOperands<0b111, "hint\t#7">;
}
+// In order to be able to write readable assembly, LLVM should accept assembly
+// inputs that use pointer authentication mnemonics, even with PA disabled.
+// However, in order to be compatible with other assemblers (e.g. GAS), LLVM
+// should not emit these mnemonics unless PA is enabled.
+def : InstAlias<"paciaz", (PACIAZ), 0>;
+def : InstAlias<"pacibz", (PACIBZ), 0>;
+def : InstAlias<"autiaz", (AUTIAZ), 0>;
+def : InstAlias<"autibz", (AUTIBZ), 0>;
+def : InstAlias<"paciasp", (PACIASP), 0>;
+def : InstAlias<"pacibsp", (PACIBSP), 0>;
+def : InstAlias<"autiasp", (AUTIASP), 0>;
+def : InstAlias<"autibsp", (AUTIBSP), 0>;
+def : InstAlias<"pacia1716", (PACIA1716), 0>;
+def : InstAlias<"pacib1716", (PACIB1716), 0>;
+def : InstAlias<"autia1716", (AUTIA1716), 0>;
+def : InstAlias<"autib1716", (AUTIB1716), 0>;
+def : InstAlias<"xpaclri", (XPACLRI), 0>;
+
// These pointer authentication instructions require armv8.3a
let Predicates = [HasPA] in {
- // When compiling with PA, there is a better mnemonic for these instructions.
+ // When PA is enabled, a better mnemonic should be emitted.
def : InstAlias<"paciaz", (PACIAZ), 1>;
def : InstAlias<"pacibz", (PACIBZ), 1>;
def : InstAlias<"autiaz", (AUTIAZ), 1>;
diff --git a/llvm/test/MC/AArch64/armv8.3a-signed-pointer.s b/llvm/test/MC/AArch64/armv8.3a-signed-pointer.s
index b804889726e7..dad4bc667853 100644
--- a/llvm/test/MC/AArch64/armv8.3a-signed-pointer.s
+++ b/llvm/test/MC/AArch64/armv8.3a-signed-pointer.s
@@ -2,7 +2,7 @@
// RUN: FileCheck --check-prefixes=CHECK,ALL %s
// RUN: not llvm-mc -triple aarch64-none-linux-gnu -show-encoding %s -o - > %t.1 2>%t.2
-// RUN: FileCheck --check-prefixes=ALL %s < %t.1
+// RUN: FileCheck --check-prefixes=NO83,ALL %s < %t.1
// RUN: FileCheck --check-prefix=CHECK-REQ %s < %t.2
// ALL: .text
@@ -98,56 +98,43 @@
// ALL-EMPTY:
paciasp
// CHECK-NEXT: paciasp // encoding: [0x3f,0x23,0x03,0xd5]
-// CHECK-REQ: error: instruction requires: pa
-// CHECK-REQ-NEXT: paciasp
+// NO83-NEXT: hint #25 // encoding: [0x3f,0x23,0x03,0xd5]
autiasp
// CHECK-NEXT: autiasp // encoding: [0xbf,0x23,0x03,0xd5]
-// CHECK-REQ: error: instruction requires: pa
-// CHECK-REQ-NEXT: autiasp
+// NO83-NEXT: hint #29 // encoding: [0xbf,0x23,0x03,0xd5]
paciaz
// CHECK-NEXT: paciaz // encoding: [0x1f,0x23,0x03,0xd5]
-// CHECK-REQ: error: instruction requires: pa
-// CHECK-REQ-NEXT: paciaz
+// NO83-NEXT: hint #24 // encoding: [0x1f,0x23,0x03,0xd5]
autiaz
// CHECK-NEXT: autiaz // encoding: [0x9f,0x23,0x03,0xd5]
-// CHECK-REQ: error: instruction requires: pa
-// CHECK-REQ-NEXT: autiaz
+// NO83-NEXT: hint #28 // encoding: [0x9f,0x23,0x03,0xd5]
pacia1716
// CHECK-NEXT: pacia1716 // encoding: [0x1f,0x21,0x03,0xd5]
-// CHECK-REQ: error: instruction requires: pa
-// CHECK-REQ-NEXT: pacia1716
+// NO83-NEXT: hint #8 // encoding: [0x1f,0x21,0x03,0xd5]
autia1716
// CHECK-NEXT: autia1716 // encoding: [0x9f,0x21,0x03,0xd5]
-// CHECK-REQ: error: instruction requires: pa
-// CHECK-REQ-NEXT: autia1716
+// NO83-NEXT: hint #12 // encoding: [0x9f,0x21,0x03,0xd5]
pacibsp
// CHECK-NEXT: pacibsp // encoding: [0x7f,0x23,0x03,0xd5]
-// CHECK-REQ: error: instruction requires: pa
-// CHECK-REQ-NEXT: pacibsp
+// NO83-NEXT: hint #27 // encoding: [0x7f,0x23,0x03,0xd5]
autibsp
// CHECK-NEXT: autibsp // encoding: [0xff,0x23,0x03,0xd5]
-// CHECK-REQ: error: instruction requires: pa
-// CHECK-REQ-NEXT: autibsp
+// NO83-NEXT: hint #31 // encoding: [0xff,0x23,0x03,0xd5]
pacibz
// CHECK-NEXT: pacibz // encoding: [0x5f,0x23,0x03,0xd5]
-// CHECK-REQ: error: instruction requires: pa
-// CHECK-REQ-NEXT: pacibz
+// NO83-NEXT: hint #26 // encoding: [0x5f,0x23,0x03,0xd5]
autibz
// CHECK-NEXT: autibz // encoding: [0xdf,0x23,0x03,0xd5]
-// CHECK-REQ: error: instruction requires: pa
-// CHECK-REQ-NEXT: autibz
+// NO83-NEXT: hint #30 // encoding: [0xdf,0x23,0x03,0xd5]
pacib1716
// CHECK-NEXT: pacib1716 // encoding: [0x5f,0x21,0x03,0xd5]
-// CHECK-REQ: error: instruction requires: pa
-// CHECK-REQ-NEXT: pacib1716
+// NO83-NEXT: hint #10 // encoding: [0x5f,0x21,0x03,0xd5]
autib1716
// CHECK-NEXT: autib1716 // encoding: [0xdf,0x21,0x03,0xd5]
-// CHECK-REQ: error: instruction requires: pa
-// CHECK-REQ-NEXT: autib1716
+// NO83-NEXT: hint #14 // encoding: [0xdf,0x21,0x03,0xd5]
xpaclri
// CHECK-NEXT: xpaclri // encoding: [0xff,0x20,0x03,0xd5]
-// CHECK-REQ: error: instruction requires: pa
-// CHECK-REQ-NEXT: xpaclri
+// NO83-NEXT: hint #7 // encoding: [0xff,0x20,0x03,0xd5]
// ALL-EMPTY:
pacia x0, x1
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