llvm-mirror/test/CodeGen/AArch64/extern-weak.ll
David Green 61ff754920 [AArch64] Add Tiny Code Model for AArch64
This adds the plumbing for the Tiny code model for the AArch64 backend. This,
instead of loading addresses through the normal ADRP;ADD pair used in the Small
model, uses a single ADR. The 21 bit range of an ADR means that the code and
its statically defined symbols need to be within 1MB of each other.

This makes it mostly interesting for embedded applications where we want to fit
as much as we can in as small a space as possible.

Differential Revision: https://reviews.llvm.org/D49673

llvm-svn: 340397
2018-08-22 11:31:39 +00:00

68 lines
2.2 KiB
LLVM

; RUN: llc -mtriple=aarch64-none-linux-gnu -relocation-model=pic -o - %s | FileCheck %s
; RUN: llc -mtriple=aarch64-none-linux-gnu -relocation-model=static -o - < %s | FileCheck %s
; RUN: llc -mtriple=aarch64-none-linux-gnu -code-model=large -o - %s | FileCheck --check-prefix=CHECK-LARGE %s
; RUN: llc -mtriple=aarch64-none-none-eabi -code-model=tiny -o - %s | FileCheck --check-prefix=CHECK-TINY %s
declare extern_weak i32 @var()
define i32()* @foo() {
; The usual ADRP/ADD pair can't be used for a weak reference because it must
; evaluate to 0 if the symbol is undefined. We use a GOT entry for PIC
; otherwise a litpool entry.
ret i32()* @var
; CHECK: adrp x[[ADDRHI:[0-9]+]], :got:var
; CHECK: ldr x0, [x[[ADDRHI]], :got_lo12:var]
; In the large model, the usual relocations are absolute and can
; materialise 0.
; CHECK-LARGE: movz x0, #:abs_g0_nc:var
; CHECK-LARGE: movk x0, #:abs_g1_nc:var
; CHECK-LARGE: movk x0, #:abs_g2_nc:var
; CHECK-LARGE: movk x0, #:abs_g3:var
; In the tiny codemodel we us a got relocated LDR.
; CHECK-TINY: ldr x0, :got:var
}
@arr_var = extern_weak global [10 x i32]
define i32* @bar() {
%addr = getelementptr [10 x i32], [10 x i32]* @arr_var, i32 0, i32 5
; CHECK: adrp x[[ADDRHI:[0-9]+]], :got:arr_var
; CHECK: ldr [[BASE:x[0-9]+]], [x[[ADDRHI]], :got_lo12:arr_var]
; CHECK: add x0, [[BASE]], #20
ret i32* %addr
; In the large model, the usual relocations are absolute and can
; materialise 0.
; CHECK-LARGE: movz [[ADDR:x[0-9]+]], #:abs_g0_nc:arr_var
; CHECK-LARGE: movk [[ADDR]], #:abs_g1_nc:arr_var
; CHECK-LARGE: movk [[ADDR]], #:abs_g2_nc:arr_var
; CHECK-LARGE: movk [[ADDR]], #:abs_g3:arr_var
; CHECK-TINY: ldr [[BASE:x[0-9]+]], :got:arr_var
; CHECK-TINY: add x0, [[BASE]], #20
}
@defined_weak_var = internal unnamed_addr global i32 0
define i32* @wibble() {
ret i32* @defined_weak_var
; CHECK: adrp [[BASE:x[0-9]+]], defined_weak_var
; CHECK: add x0, [[BASE]], :lo12:defined_weak_var
; CHECK-LARGE: movz x0, #:abs_g0_nc:defined_weak_var
; CHECK-LARGE: movk x0, #:abs_g1_nc:defined_weak_var
; CHECK-LARGE: movk x0, #:abs_g2_nc:defined_weak_var
; CHECK-LARGE: movk x0, #:abs_g3:defined_weak_var
; CHECK-TINY: adr x0, defined_weak_var
}