From: Thomas Preud'homme Date: Mon, 24 Apr 2017 13:49:48 +0000 (+0100) Subject: [GAS/ARM] Fix expansion of ldr pseudo instruction X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=534455547021f3262fa60d32cabb626af01692a3;p=binutils-gdb.git [GAS/ARM] Fix expansion of ldr pseudo instruction The LDR rX, =cst pseudo-instruction suffers from two issues for loading integer constants in Thumb mode: - movs is used if the constant and register can be encoded using that instruction which leads to unexpected behavior due to its flag-setting behavior - mov.w, movw and mvn are used for r13 (sp) and r15 (pc) but these encoding are marked as UNPREDICTABLE This patch fixes those issues and update testing accordingly. 2017-04-24 Thomas Preud'homme gas/ * config/tc-arm.c (move_or_literal_pool): Remove code generating MOVS. Forbid MOV.W and MOVW if destination is SP or PC. * testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.s: Explain expectation of LDR not generating a MOVS for low registers and small constants. Add tests of MOVW generation. * testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.d: Update expected disassembly. --- diff --git a/gas/ChangeLog b/gas/ChangeLog index c5531a76861..7c9697bd045 100644 --- a/gas/ChangeLog +++ b/gas/ChangeLog @@ -1,3 +1,13 @@ +2017-04-24 Thomas Preud'homme + + * config/tc-arm.c (move_or_literal_pool): Remove code generating MOVS. + Forbid MOV.W and MOVW if destination is SP or PC. + * testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.s: Explain + expectation of LDR not generating a MOVS for low registers and small + constants. Add tests of MOVW generation. + * testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.d: Update + expected disassembly. + 2017-04-22 Alan Modra * testsuite/gas/ppc/vle.s: Format. Add se_rfgi and e_sc. diff --git a/gas/config/tc-arm.c b/gas/config/tc-arm.c index 83244b70473..7e35c348d20 100644 --- a/gas/config/tc-arm.c +++ b/gas/config/tc-arm.c @@ -7959,17 +7959,13 @@ move_or_literal_pool (int i, enum lit_type t, bfd_boolean mode_3) { if (thumb_p) { - /* This can be encoded only for a low register. */ - if ((v & ~0xFF) == 0 && (inst.operands[i].reg < 8)) - { - /* This can be done with a mov(1) instruction. */ - inst.instruction = T_OPCODE_MOV_I8 | (inst.operands[i].reg << 8); - inst.instruction |= v; - return TRUE; - } + /* LDR should not use lead in a flag-setting instruction being + chosen so we do not check whether movs can be used. */ - if (ARM_CPU_HAS_FEATURE (cpu_variant, arm_ext_v6t2) + if ((ARM_CPU_HAS_FEATURE (cpu_variant, arm_ext_v6t2) || ARM_CPU_HAS_FEATURE (cpu_variant, arm_ext_v6t2_v8m)) + && inst.operands[i].reg != 13 + && inst.operands[i].reg != 15) { /* Check if on thumb2 it can be done with a mov.w, mvn or movw instruction. */ diff --git a/gas/testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.d b/gas/testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.d index 55b5f17887f..7afc1350e53 100644 --- a/gas/testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.d +++ b/gas/testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.d @@ -6,19 +6,23 @@ .*: +file format .*arm.* Disassembly of section \.text: -0[0-9a-f]+ <[^>]+> 2000[[:space:]]+movs[[:space:]]+r0, #0.* -0[0-9a-f]+ <[^>]+> 2108[[:space:]]+movs[[:space:]]+r1, #8.* -0[0-9a-f]+ <[^>]+> 2251[[:space:]]+movs[[:space:]]+r2, #81.* -0[0-9a-f]+ <[^>]+> 231f[[:space:]]+movs[[:space:]]+r3, #31.* -0[0-9a-f]+ <[^>]+> 242f[[:space:]]+movs[[:space:]]+r4, #47.* -0[0-9a-f]+ <[^>]+> 253f[[:space:]]+movs[[:space:]]+r5, #63.* -0[0-9a-f]+ <[^>]+> 2680[[:space:]]+movs[[:space:]]+r6, #128.* -0[0-9a-f]+ <[^>]+> 27ff[[:space:]]+movs[[:space:]]+r7, #255.* +0[0-9a-f]+ <[^>]+> f04f 0000[[:space:]]+mov\.w[[:space:]]+r0, #0.* +0[0-9a-f]+ <[^>]+> f04f 0108[[:space:]]+mov\.w[[:space:]]+r1, #8.* +0[0-9a-f]+ <[^>]+> f04f 0251[[:space:]]+mov\.w[[:space:]]+r2, #81.* +0[0-9a-f]+ <[^>]+> f04f 031f[[:space:]]+mov\.w[[:space:]]+r3, #31.* +0[0-9a-f]+ <[^>]+> f04f 042f[[:space:]]+mov\.w[[:space:]]+r4, #47.* +0[0-9a-f]+ <[^>]+> f04f 053f[[:space:]]+mov\.w[[:space:]]+r5, #63.* +0[0-9a-f]+ <[^>]+> f04f 0680[[:space:]]+mov\.w[[:space:]]+r6, #128.* +0[0-9a-f]+ <[^>]+> f04f 07ff[[:space:]]+mov\.w[[:space:]]+r7, #255.* 0[0-9a-f]+ <[^>]+> f04f 0800[[:space:]]+mov\.w[[:space:]]+r8, #0.* 0[0-9a-f]+ <[^>]+> f04f 0908[[:space:]]+mov\.w[[:space:]]+r9, #8.* 0[0-9a-f]+ <[^>]+> f04f 0a51[[:space:]]+mov\.w[[:space:]]+sl, #81.* 0[0-9a-f]+ <[^>]+> f04f 0b1f[[:space:]]+mov\.w[[:space:]]+fp, #31.* 0[0-9a-f]+ <[^>]+> f04f 0c2f[[:space:]]+mov\.w[[:space:]]+ip, #47.* -0[0-9a-f]+ <[^>]+> f04f 0d3f[[:space:]]+mov\.w[[:space:]]+sp, #63.* 0[0-9a-f]+ <[^>]+> f04f 0e80[[:space:]]+mov\.w[[:space:]]+lr, #128.* -0[0-9a-f]+ <[^>]+> f04f 0fff[[:space:]]+mov\.w[[:space:]]+pc, #255.* +0[0-9a-f]+ <[^>]+> f64f 78ff[[:space:]]+movw[[:space:]]+r8, #65535.* +0[0-9a-f]+ <[^>]+> f24f 09f0[[:space:]]+movw[[:space:]]+r9, #61680.* +0[0-9a-f]+ <[^>]+> f8df d004[[:space:]]+ldr\.w[[:space:]]+sp, \[pc, #4\].* +0[0-9a-f]+ <[^>]+> f8df f004[[:space:]]+ldr\.w[[:space:]]+pc, \[pc, #4\].* +0[0-9a-f]+ <[^>]+> 0000003f[[:space:]]+.word[[:space:]]+0x0000003f.* +0[0-9a-f]+ <[^>]+> 000000ff[[:space:]]+.word[[:space:]]+0x000000ff.* diff --git a/gas/testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.s b/gas/testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.s index d2254101860..b4738572236 100644 --- a/gas/testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.s +++ b/gas/testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.s @@ -2,8 +2,8 @@ .syntax unified .thumb_func thumb2_ldr: - # These can be encoded into movs since constant is small - # And register can be encoded in 3 bits + # These must be encoded into mov.w despite constant and register being + # small enough as ldr should not generate a flag-setting instruction. ldr r0,=0x00 ldr r1,=0x08 ldr r2,=0x51 @@ -12,13 +12,19 @@ thumb2_ldr: ldr r5,=0x3F ldr r6,=0x80 ldr r7,=0xFF - # These shall be encoded into mov.w - # Since register cannot be encoded in 3 bits + # These shall be encoded into mov.w since register cannot be encoded in + # 3 bits ldr r8,=0x00 ldr r9,=0x08 ldr r10,=0x51 ldr r11,=0x1F ldr r12,=0x2F - ldr r13,=0x3F ldr r14,=0x80 + # These shall be encoded into movw since immediate cannot be encoded + # with mov.w + ldr r8,=0xFFFF + ldr r9,=0xF0F0 + # These should be encoded as ldr since mov immediate is unpredictable + # for sp and pc + ldr r13,=0x3F ldr r15,=0xFF