llvm/test/MC/ARM/ldr-pseudo-darwin.s
David Peixotto 0fa193b086 Implement the ldr-pseudo opcode for ARM assembly
The ldr-pseudo opcode is a convenience for loading 32-bit constants.
It is converted into a pc-relative load from a constant pool. For
example,

  ldr r0, =0x10001
  ldr r1, =bar

will generate this output in the final assembly

  ldr r0, .Ltmp0
  ldr r1, .Ltmp1
  ...
  .Ltmp0: .long 0x10001
  .Ltmp1: .long bar

Sketch of the LDR pseudo implementation:
  Keep a map from Section => ConstantPool

  When parsing ldr r0, =val
    parse val as an MCExpr
    get ConstantPool for current Section
    Label = CreateTempSymbol()
    remember val in ConstantPool at next free slot
    add operand to ldr that is MCSymbolRef of Label

  On finishParse() callback
    Write out all non-empty constant pools
    for each Entry in ConstantPool
      Emit Entry.Label
      Emit Entry.Value

Possible improvements to be added in a later patch:
  1. Does not convert load of small constants to mov
     (e.g. ldr r0, =0x1 => mov r0, 0x1)
  2. Does reuse constant pool entries for same constant

The implementation was tested for ARM, Thumb1, and Thumb2 targets on
linux and darwin.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197708 91177308-0d34-0410-b5e6-96231b3b80d8
2013-12-19 18:12:36 +00:00

242 lines
5.2 KiB
ArmAsm

@ This test has a partner (ldr-pseudo.s) that contains matching
@ tests for the ldr-pseudo on linux targets. We need separate files
@ because the syntax for switching sections and temporary labels differs
@ between darwin and linux. Any tests added here should have a matching
@ test added there.
@RUN: llvm-mc -triple armv7-apple-darwin %s | FileCheck %s
@RUN: llvm-mc -triple thumbv5-apple-darwin %s | FileCheck %s
@RUN: llvm-mc -triple thumbv7-apple-darwin %s | FileCheck %s
@
@ Check that large constants are converted to ldr from constant pool
@
@ simple test
.section __TEXT,b,regular,pure_instructions
@ CHECK-LABEL: f3:
f3:
ldr r0, =0x10001
@ CHECK: ldr r0, Ltmp0
@ loading multiple constants
.section __TEXT,c,regular,pure_instructions
@ CHECK-LABEL: f4:
f4:
ldr r0, =0x10002
@ CHECK: ldr r0, Ltmp1
adds r0, r0, #1
adds r0, r0, #1
adds r0, r0, #1
adds r0, r0, #1
ldr r0, =0x10003
@ CHECK: ldr r0, Ltmp2
adds r0, r0, #1
adds r0, r0, #1
@ TODO: the same constants should have the same constant pool location
.section __TEXT,d,regular,pure_instructions
@ CHECK-LABEL: f5:
f5:
ldr r0, =0x10004
@ CHECK: ldr r0, Ltmp3
adds r0, r0, #1
adds r0, r0, #1
adds r0, r0, #1
adds r0, r0, #1
adds r0, r0, #1
adds r0, r0, #1
adds r0, r0, #1
ldr r0, =0x10004
@ CHECK: ldr r0, Ltmp4
adds r0, r0, #1
adds r0, r0, #1
adds r0, r0, #1
adds r0, r0, #1
adds r0, r0, #1
adds r0, r0, #1
@ a section defined in multiple pieces should be merged and use a single constant pool
.section __TEXT,e,regular,pure_instructions
@ CHECK-LABEL: f6:
f6:
ldr r0, =0x10006
@ CHECK: ldr r0, Ltmp5
adds r0, r0, #1
adds r0, r0, #1
adds r0, r0, #1
.section __TEXT,f,regular,pure_instructions
@ CHECK-LABEL: f7:
f7:
adds r0, r0, #1
adds r0, r0, #1
adds r0, r0, #1
.section __TEXT,e,regular,pure_instructions
@ CHECK-LABEL: f8:
f8:
adds r0, r0, #1
ldr r0, =0x10007
@ CHECK: ldr r0, Ltmp6
adds r0, r0, #1
adds r0, r0, #1
@
@ Check that symbols can be loaded using ldr pseudo
@
@ load an undefined symbol
.section __TEXT,g,regular,pure_instructions
@ CHECK-LABEL: f9:
f9:
ldr r0, =foo
@ CHECK: ldr r0, Ltmp7
@ load a symbol from another section
.section __TEXT,h,regular,pure_instructions
@ CHECK-LABEL: f10:
f10:
ldr r0, =f5
@ CHECK: ldr r0, Ltmp8
@ load a symbol from the same section
.section __TEXT,i,regular,pure_instructions
@ CHECK-LABEL: f11:
f11:
ldr r0, =f12
@ CHECK: ldr r0, Ltmp9
@ CHECK-LABEL: f12:
f12:
adds r0, r0, #1
adds r0, r0, #1
.section __TEXT,j,regular,pure_instructions
@ mix of symbols and constants
@ CHECK-LABEL: f13:
f13:
adds r0, r0, #1
adds r0, r0, #1
ldr r0, =0x101
@ CHECK: ldr r0, Ltmp10
adds r0, r0, #1
adds r0, r0, #1
ldr r0, =bar
@ CHECK: ldr r0, Ltmp11
adds r0, r0, #1
adds r0, r0, #1
@
@ Check for correct usage in other contexts
@
@ usage in macro
.macro useit_in_a_macro
ldr r0, =0x10008
ldr r0, =baz
.endm
.section __TEXT,k,regular,pure_instructions
@ CHECK-LABEL: f14:
f14:
useit_in_a_macro
@ CHECK: ldr r0, Ltmp12
@ CHECK: ldr r0, Ltmp13
@ usage with expressions
.section __TEXT,l,regular,pure_instructions
@ CHECK-LABEL: f15:
f15:
ldr r0, =0x10001+8
@ CHECK: ldr r0, Ltmp14
adds r0, r0, #1
ldr r0, =bar+4
@ CHECK: ldr r0, Ltmp15
adds r0, r0, #1
@
@ Constant Pools
@
@ CHECK: .section __TEXT,b,regular,pure_instructions
@ CHECK: .align 2
@ CHECK: .data_region
@ CHECK-LABEL: Ltmp0:
@ CHECK: .long 65537
@ CHECK: .end_data_region
@ CHECK: .section __TEXT,c,regular,pure_instructions
@ CHECK: .align 2
@ CHECK: .data_region
@ CHECK-LABEL: Ltmp1:
@ CHECK: .long 65538
@ CHECK-LABEL: Ltmp2:
@ CHECK: .long 65539
@ CHECK: .end_data_region
@ CHECK: .section __TEXT,d,regular,pure_instructions
@ CHECK: .align 2
@ CHECK: .data_region
@ CHECK-LABEL: Ltmp3:
@ CHECK: .long 65540
@ CHECK-LABEL: Ltmp4:
@ CHECK: .long 65540
@ CHECK: .end_data_region
@ CHECK: .section __TEXT,e,regular,pure_instructions
@ CHECK: .align 2
@ CHECK: .data_region
@ CHECK-LABEL: Ltmp5:
@ CHECK: .long 65542
@ CHECK-LABEL: Ltmp6:
@ CHECK: .long 65543
@ CHECK: .end_data_region
@ Should not switch to section because it has no constant pool
@ CHECK-NOT: .section __TEXT,f,regular,pure_instructions
@ CHECK: .section __TEXT,g,regular,pure_instructions
@ CHECK: .align 2
@ CHECK: .data_region
@ CHECK-LABEL: Ltmp7:
@ CHECK: .long foo
@ CHECK: .end_data_region
@ CHECK: .section __TEXT,h,regular,pure_instructions
@ CHECK: .align 2
@ CHECK: .data_region
@ CHECK-LABEL: Ltmp8:
@ CHECK: .long f5
@ CHECK: .end_data_region
@ CHECK: .section __TEXT,i,regular,pure_instructions
@ CHECK: .align 2
@ CHECK: .data_region
@ CHECK-LABEL: Ltmp9:
@ CHECK: .long f12
@ CHECK: .end_data_region
@ CHECK: .section __TEXT,j,regular,pure_instructions
@ CHECK: .align 2
@ CHECK: .data_region
@ CHECK-LABEL: Ltmp10:
@ CHECK: .long 257
@ CHECK-LABEL: Ltmp11:
@ CHECK: .long bar
@ CHECK: .end_data_region
@ CHECK: .section __TEXT,k,regular,pure_instructions
@ CHECK: .align 2
@ CHECK: .data_region
@ CHECK-LABEL: Ltmp12:
@ CHECK: .long 65544
@ CHECK-LABEL: Ltmp13:
@ CHECK: .long baz
@ CHECK: .end_data_region
@ CHECK: .section __TEXT,l,regular,pure_instructions
@ CHECK: .align 2
@ CHECK: .data_region
@ CHECK-LABEL: Ltmp14:
@ CHECK: .long 65545
@ CHECK-LABEL: Ltmp15:
@ CHECK: .long bar+4
@ CHECK: .end_data_region