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llvm-project/llvm/test/CodeGen/ARM/2010-11-29-PrologueBug.ll

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ARM: stop emitting blx instructions for most calls on MachO. I'm really not sure why we were in the first place, it's the linker's job to convert between BL/BLX as necessary. Even worse, using BLX left Thumb calls that could be locally resolved completely unencodable since all offsets to BLX are multiples of 4. rdar://26182344 llvm-svn: 269101
2016-05-11 03:17:47 +08:00
; RUN: llc < %s -mtriple=armv7-apple-ios | FileCheck %s
; RUN: llc < %s -mtriple=thumbv7-apple-ios | FileCheck %s
Mark Darwin call instructions as using "r7" to prevent the frame-register assignment instructions from being moved below / above calls. rdar://8690640 llvm-svn: 120339
2010-11-30 06:43:27 +08:00
; rdar://8690640
[ARM] Generate consistent frame records for Thumb2 There is not an official documented ABI for frame pointers in Thumb2, but we should try to emit something which is useful. We use r7 as the frame pointer for Thumb code, which currently means that if a function needs to save a high register (r8-r11), it will get pushed to the stack between the frame pointer (r7) and link register (r14). This means that while a stack unwinder can follow the chain of frame pointers up the stack, it cannot know the offset to lr, so does not know which functions correspond to the stack frames. To fix this, we need to push the callee-saved registers in two batches, with the first push saving the low registers, fp and lr, and the second push saving the high registers. This is already implemented, but previously only used for iOS. This patch turns it on for all Thumb2 targets when frame pointers are required by the ABI, and the frame pointer is r7 (Windows uses r11, so this isn't a problem there). If frame pointer elimination is enabled we still emit a single push/pop even if we need a frame pointer for other reasons, to avoid increasing code size. We must also ensure that lr is pushed to the stack when using a frame pointer, so that we end up with a complete frame record. Situations that could cause this were rare, because we already push lr in most situations so that we can return using the pop instruction. Differential Revision: https://reviews.llvm.org/D23516 llvm-svn: 279506
2016-08-23 17:19:22 +08:00
define i32* @t(i32* %x) nounwind "no-frame-pointer-elim"="true" {
Mark Darwin call instructions as using "r7" to prevent the frame-register assignment instructions from being moved below / above calls. rdar://8690640 llvm-svn: 120339
2010-11-30 06:43:27 +08:00
entry:
ARM: stop emitting blx instructions for most calls on MachO. I'm really not sure why we were in the first place, it's the linker's job to convert between BL/BLX as necessary. Even worse, using BLX left Thumb calls that could be locally resolved completely unencodable since all offsets to BLX are multiples of 4. rdar://26182344 llvm-svn: 269101
2016-05-11 03:17:47 +08:00
; CHECK-LABEL: t:
; CHECK: push
; CHECK: mov r7, sp
; CHECK: bl _foo
; CHECK: bl _foo
; CHECK: bl _foo
; CHECK: pop {r7, pc}
Mark Darwin call instructions as using "r7" to prevent the frame-register assignment instructions from being moved below / above calls. rdar://8690640 llvm-svn: 120339
2010-11-30 06:43:27 +08:00
%0 = tail call i32* @foo(i32* %x) nounwind
%1 = tail call i32* @foo(i32* %0) nounwind
%2 = tail call i32* @foo(i32* %1) nounwind
ret i32* %2
}
declare i32* @foo(i32*)