Add BL (immediate) and BLX (register) to ARM assembler.

tests_lit/assembler/arm32/blx.ll

+; Show that we know how to translate add.
+
+; NOTE: We use -O2 to get rid of memory stores.
+
+; REQUIRES: allow_dump
+
+; Compile using standalone assembler.
+; RUN: %p2i --filetype=asm -i %s --target=arm32 --args -O2 \
+; RUN:   | FileCheck %s --check-prefix=ASM
+
+; Show bytes in assembled standalone code.
+; RUN: %p2i --filetype=asm -i %s --target=arm32 --assemble --disassemble \
+; RUN:   --args -O2 | FileCheck %s --check-prefix=DIS
+
+; Compile using integrated assembler.
+; RUN: %p2i --filetype=iasm -i %s --target=arm32 --args -O2 \
+; RUN:   | FileCheck %s --check-prefix=IASM
+
+; Show bytes in assembled integrated code.
+; RUN: %p2i --filetype=iasm -i %s --target=arm32 --assemble --disassemble \
+; RUN:   --args -O2 | FileCheck %s --check-prefix=DIS
+
+define internal void @callIndirect(i32 %addr) {
+; ASM-LABEL:callIndirect:
+; DIS-LABEL:00000000 <callIndirect>:
+; IASM-LABEL:callIndirect:
+
+entry:
+; ASM-NEXT:.LcallIndirect$entry:
+; IASM-NEXT:.LcallIndirect$entry:
+; ASM-NEXT:     push    {lr}
+; DIS-NEXT:   0:        e52de004
+; IASM-NEXT:    .byte 0x4
+; IASM-NEXT:    .byte 0xe0
+; IASM-NEXT:    .byte 0x2d
+; IASM-NEXT:    .byte 0xe5
+
+; ASM-NEXT:     sub     sp, sp, #12
+; DIS-NEXT:   4:        e24dd00c
+; IASM-NEXT:    .byte 0xc
+; IASM-NEXT:    .byte 0xd0
+; IASM-NEXT:    .byte 0x4d
+; IASM-NEXT:    .byte 0xe2
+
+   %calladdr = inttoptr i32 %addr to void (i32)*
+
+; ASM-NEXT:     mov     r1, r0
+; DIS-NEXT:   8:        e1a01000
+; IASM-NEXT:    .byte 0x0
+; IASM-NEXT:    .byte 0x10
+; IASM-NEXT:    .byte 0xa0
+; IASM-NEXT:    .byte 0xe1
+
+   call void %calladdr(i32 %addr)
+
+; ASM-NEXT:     blx     r1
+; DIS-NEXT:   c:        e12fff31
+; IASM-NEXT:    .byte 0x31
+; IASM-NEXT:    .byte 0xff
+; IASM-NEXT:    .byte 0x2f
+; IASM-NEXT:    .byte 0xe1
+
+   ret void
+}