[llvm-branch-commits] [llvm] 4c96b36 - [X86] -fpatchable-function-entry=N, 0: place patch label after ENDBR{32, 64}
Hans Wennborg via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Wed Feb 5 06:19:18 PST 2020
Author: Fangrui Song
Date: 2020-02-05T15:19:04+01:00
New Revision: 4c96b369a074e93a0be536dd795d3f245ef6f18b
URL: https://github.com/llvm/llvm-project/commit/4c96b369a074e93a0be536dd795d3f245ef6f18b
DIFF: https://github.com/llvm/llvm-project/commit/4c96b369a074e93a0be536dd795d3f245ef6f18b.diff
LOG: [X86] -fpatchable-function-entry=N,0: place patch label after ENDBR{32,64}
Similar to D73680 (AArch64 BTI).
A local linkage function whose address is not taken does not need ENDBR32/ENDBR64. Placing the patch label after ENDBR32/ENDBR64 has the advantage that code does not need to differentiate whether the function has an initial ENDBR.
Also, add 32-bit tests and test that .cfi_startproc is at the function
entry. The line information has a general implementation and is tested
by AArch64/patchable-function-entry-empty.mir
Reviewed By: nickdesaulniers
Differential Revision: https://reviews.llvm.org/D73760
(cherry picked from commit 8ff86fcf4c038c7156ed4f01e7ed35cae49489e2)
Added:
Modified:
llvm/lib/Target/X86/X86MCInstLower.cpp
llvm/test/CodeGen/AArch64/patchable-function-entry-bti.ll
llvm/test/CodeGen/X86/patchable-function-entry-ibt.ll
Removed:
################################################################################
diff --git a/llvm/lib/Target/X86/X86MCInstLower.cpp b/llvm/lib/Target/X86/X86MCInstLower.cpp
index 2fc9a2af01d7..7f49c6e861d4 100644
--- a/llvm/lib/Target/X86/X86MCInstLower.cpp
+++ b/llvm/lib/Target/X86/X86MCInstLower.cpp
@@ -2002,6 +2002,25 @@ void X86AsmPrinter::EmitInstruction(const MachineInstr *MI) {
break;
}
+ case X86::ENDBR32:
+ case X86::ENDBR64: {
+ // CurrentPatchableFunctionEntrySym can be CurrentFnBegin only for
+ // -fpatchable-function-entry=N,0. The entry MBB is guaranteed to be
+ // non-empty. If MI is the initial ENDBR, place the
+ // __patchable_function_entries label after ENDBR.
+ if (CurrentPatchableFunctionEntrySym &&
+ CurrentPatchableFunctionEntrySym == CurrentFnBegin &&
+ MI == &MF->front().front()) {
+ MCInst Inst;
+ MCInstLowering.Lower(MI, Inst);
+ EmitAndCountInstruction(Inst);
+ CurrentPatchableFunctionEntrySym = createTempSymbol("patch");
+ OutStreamer->EmitLabel(CurrentPatchableFunctionEntrySym);
+ return;
+ }
+ break;
+ }
+
case X86::TAILJMPr:
case X86::TAILJMPm:
case X86::TAILJMPd:
diff --git a/llvm/test/CodeGen/AArch64/patchable-function-entry-bti.ll b/llvm/test/CodeGen/AArch64/patchable-function-entry-bti.ll
index 4b85664673fd..19386e94383d 100644
--- a/llvm/test/CodeGen/AArch64/patchable-function-entry-bti.ll
+++ b/llvm/test/CodeGen/AArch64/patchable-function-entry-bti.ll
@@ -15,7 +15,8 @@ define void @f0() "patchable-function-entry"="0" "branch-target-enforcement" {
define void @f1() "patchable-function-entry"="1" "branch-target-enforcement" {
; CHECK-LABEL: f1:
; CHECK-NEXT: .Lfunc_begin1:
-; CHECK: // %bb.0:
+; CHECK-NEXT: .cfi_startproc
+; CHECK-NEXT: // %bb.0:
; CHECK-NEXT: hint #34
; CHECK-NEXT: .Lpatch0:
; CHECK-NEXT: nop
@@ -33,7 +34,8 @@ define void @f2_1() "patchable-function-entry"="1" "patchable-function-prefix"="
; CHECK-NEXT: nop
; CHECK-NEXT: f2_1:
; CHECK-NEXT: .Lfunc_begin2:
-; CHECK: // %bb.0:
+; CHECK-NEXT: .cfi_startproc
+; CHECK-NEXT: // %bb.0:
; CHECK-NEXT: hint #34
; CHECK-NEXT: nop
; CHECK-NEXT: ret
diff --git a/llvm/test/CodeGen/X86/patchable-function-entry-ibt.ll b/llvm/test/CodeGen/X86/patchable-function-entry-ibt.ll
index 49a36b2205ce..3def5a378458 100644
--- a/llvm/test/CodeGen/X86/patchable-function-entry-ibt.ll
+++ b/llvm/test/CodeGen/X86/patchable-function-entry-ibt.ll
@@ -1,26 +1,37 @@
-; RUN: llc -mtriple=x86_64 %s -o - | FileCheck --check-prefixes=CHECK %s
+; RUN: llc -mtriple=i686 %s -o - | FileCheck --check-prefixes=CHECK,32 %s
+; RUN: llc -mtriple=x86_64 %s -o - | FileCheck --check-prefixes=CHECK,64 %s
;; -fpatchable-function-entry=0 -fcf-protection=branch
-define void @f0() "patchable-function-entry"="0" "branch-target-enforcement" {
+define void @f0() "patchable-function-entry"="0" {
; CHECK-LABEL: f0:
; CHECK-NEXT: .Lfunc_begin0:
-; CHECK: # %bb.0:
-; CHECK-NEXT: endbr64
-; CHECK-NEXT: retq
+; CHECK-NEXT: .cfi_startproc
+; CHECK-NEXT: # %bb.0:
+; 32-NEXT: endbr32
+; 64-NEXT: endbr64
+; CHECK-NEXT: ret
; CHECK-NOT: .section __patchable_function_entries
ret void
}
;; -fpatchable-function-entry=1 -fcf-protection=branch
+;; For M=0, place the label .Lpatch0 after the initial ENDBR.
+;; .cfi_startproc should be placed at the function entry.
define void @f1() "patchable-function-entry"="1" {
; CHECK-LABEL: f1:
; CHECK-NEXT: .Lfunc_begin1:
-; CHECK: endbr64
+; CHECK-NEXT: .cfi_startproc
+; CHECK-NEXT: # %bb.0:
+; 32-NEXT: endbr32
+; 64-NEXT: endbr64
+; CHECK-NEXT: .Lpatch0:
; CHECK-NEXT: nop
-; CHECK-NEXT: retq
+; CHECK-NEXT: ret
; CHECK: .section __patchable_function_entries,"awo", at progbits,f1,unique,0
-; CHECK-NEXT: .p2align 3
-; CHECK-NEXT: .quad .Lfunc_begin1
+; 32-NEXT: .p2align 2
+; 32-NEXT: .long .Lpatch0
+; 64-NEXT: .p2align 3
+; 64-NEXT: .quad .Lpatch0
ret void
}
@@ -31,15 +42,44 @@ define void @f2_1() "patchable-function-entry"="1" "patchable-function-prefix"="
; CHECK-NEXT: nop
; CHECK-NEXT: f2_1:
; CHECK-NEXT: .Lfunc_begin2:
-; CHECK: # %bb.0:
-; CHECK-NEXT: endbr64
+; CHECK-NEXT: .cfi_startproc
+; CHECK-NEXT: # %bb.0:
+; 32-NEXT: endbr32
+; 64-NEXT: endbr64
; CHECK-NEXT: nop
-; CHECK-NEXT: retq
+; CHECK-NEXT: ret
; CHECK: .Lfunc_end2:
; CHECK-NEXT: .size f2_1, .Lfunc_end2-f2_1
; CHECK: .section __patchable_function_entries,"awo", at progbits,f1,unique,0
-; CHECK-NEXT: .p2align 3
-; CHECK-NEXT: .quad .Ltmp0
+; 32-NEXT: .p2align 2
+; 32-NEXT: .long .Ltmp0
+; 64-NEXT: .p2align 3
+; 64-NEXT: .quad .Ltmp0
+ ret void
+}
+
+;; -fpatchable-function-entry=1 -fcf-protection=branch
+;; For M=0, don't create .Lpatch0 if the initial instruction is not ENDBR,
+;; even if other basic blocks may have ENDBR.
+ at buf = internal global [5 x i8*] zeroinitializer
+declare i32 @llvm.eh.sjlj.setjmp(i8*)
+
+define internal void @f1i() "patchable-function-entry"="1" {
+; CHECK-LABEL: f1i:
+; CHECK-NEXT: .Lfunc_begin3:
+; CHECK-NEXT: .cfi_startproc
+; CHECK-NEXT: # %bb.0:
+; CHECK-NEXT: nop
+; CHECK-NOT: .Lpatch0:
+;; Another basic block has ENDBR, but it doesn't affect our decision to not create .Lpatch0
+; CHECK: endbr
+; CHECK: .section __patchable_function_entries,"awo", at progbits,f1,unique,0
+; 32-NEXT: .p2align 2
+; 32-NEXT: .long .Lfunc_begin3
+; 64-NEXT: .p2align 3
+; 64-NEXT: .quad .Lfunc_begin3
+entry:
+ tail call i32 @llvm.eh.sjlj.setjmp(i8* bitcast ([5 x i8*]* @buf to i8*))
ret void
}
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