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authorH.J. Lu <hjl.tools@gmail.com>2018-02-17 05:20:42 -0800
committerH.J. Lu <hjl.tools@gmail.com>2018-02-17 05:20:57 -0800
commit62a02d25b6e5d9f92c205260daa11355d0c62532 (patch)
tree9fa0855fa0acd81d5d855b01a865cdfb3456254a
parentbb57c12e551e7b66db9d5d8623e2f294091f03c1 (diff)
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Add .nop assembler directive
Implement the '.nop SIZE[, CONTROL]' assembler directive, which emits SIZE bytes filled with no-op instructions. SIZE is absolute expression. The optional CONTROL byte controls how no-op instructions should be generated. If the comma and @var{control} are omitted, CONTROL is assumed to be zero. For Intel 80386 and AMD x86-64 targets, CONTROL byte specifies the size limit of a single no-op instruction. The valid values of CONTROL byte are between 0 and 8 for 16-bit mode, between 0 and 10 for 32-bit mode, between 0 and 11 for 64-bit mode. When 0 is used, the no-op size limit is set to the maximum supported size. 2 new relax states, rs_space_nop and rs_fill_nop, are added to enum _relax_state, which are similar to rs_space and rs_fill, respectively, but they fill with no-op instructions, instead of a single byte. A target backend must override the default md_generate_nops to generate proper no-op instructions. Otherwise, an error of unimplemented .nop directive will be issued whenever .nop directive is used. * NEWS: Mention .nop directive. * as.h (_relax_state): Add rs_space_nop and rs_fill_nop. * read.c (potable): Add .nop. (s_nop): New function. * read.h (s_nop): New prototype. * write.c (cvt_frag_to_fill): Handle rs_space_nop and rs_fill_nop. (md_generate_nops): New function. (relax_segment): Likewise. (write_contents): Use md_generate_nops for rs_fill_nop. * config/tc-i386.c (alt64_11): New. (alt64_patt): Likewise. (md_convert_frag): Handle rs_space_nop. (i386_output_nops): New function. (i386_generate_nops): Likewise. (i386_align_code): Call i386_output_nops. * config/tc-i386.h (i386_generate_nops): New. (md_generate_nops): Likewise. * doc/as.texinfo: Document .nop directive. * testsuite/gas/i386/i386.exp: Run .nop directive tests. * testsuite/gas/i386/nop-1.d: New file. * testsuite/gas/i386/nop-1.s: Likewise. * testsuite/gas/i386/nop-2.d: Likewise. * testsuite/gas/i386/nop-2.s: Likewise. * testsuite/gas/i386/nop-3.d: Likewise. * testsuite/gas/i386/nop-3.s: Likewise. * testsuite/gas/i386/nop-4.d: Likewise. * testsuite/gas/i386/nop-4.s: Likewise. * testsuite/gas/i386/nop-5.d: Likewise. * testsuite/gas/i386/nop-5.s: Likewise. * testsuite/gas/i386/nop-6.d: Likewise. * testsuite/gas/i386/nop-6.s: Likewise. * testsuite/gas/i386/nop-bad-1.l: Likewise. * testsuite/gas/i386/nop-bad-1.s: Likewise. * testsuite/gas/i386/x86-64-nop-1.d: Likewise. * testsuite/gas/i386/x86-64-nop-2.d: Likewise. * testsuite/gas/i386/x86-64-nop-3.d: Likewise. * testsuite/gas/i386/x86-64-nop-4.d: Likewise. * testsuite/gas/i386/x86-64-nop-5.d: Likewise. * testsuite/gas/i386/x86-64-nop-6.d: Likewise.
-rw-r--r--gas/ChangeLog43
-rw-r--r--gas/NEWS3
-rw-r--r--gas/as.h10
-rw-r--r--gas/config/tc-i386.c272
-rw-r--r--gas/config/tc-i386.h5
-rw-r--r--gas/doc/as.texinfo18
-rw-r--r--gas/read.c53
-rw-r--r--gas/read.h1
-rw-r--r--gas/testsuite/gas/i386/i386.exp13
-rw-r--r--gas/testsuite/gas/i386/nop-1.d31
-rw-r--r--gas/testsuite/gas/i386/nop-1.s21
-rw-r--r--gas/testsuite/gas/i386/nop-2.d40
-rw-r--r--gas/testsuite/gas/i386/nop-2.s22
-rw-r--r--gas/testsuite/gas/i386/nop-3.d20
-rw-r--r--gas/testsuite/gas/i386/nop-3.s15
-rw-r--r--gas/testsuite/gas/i386/nop-4.d23
-rw-r--r--gas/testsuite/gas/i386/nop-4.s18
-rw-r--r--gas/testsuite/gas/i386/nop-5.d25
-rw-r--r--gas/testsuite/gas/i386/nop-5.s19
-rw-r--r--gas/testsuite/gas/i386/nop-6.d17
-rw-r--r--gas/testsuite/gas/i386/nop-6.s25
-rw-r--r--gas/testsuite/gas/i386/nop-bad-1.l4
-rw-r--r--gas/testsuite/gas/i386/nop-bad-1.s4
-rw-r--r--gas/testsuite/gas/i386/x86-64-nop-1.d32
-rw-r--r--gas/testsuite/gas/i386/x86-64-nop-2.d41
-rw-r--r--gas/testsuite/gas/i386/x86-64-nop-3.d21
-rw-r--r--gas/testsuite/gas/i386/x86-64-nop-4.d24
-rw-r--r--gas/testsuite/gas/i386/x86-64-nop-5.d26
-rw-r--r--gas/testsuite/gas/i386/x86-64-nop-6.d18
-rw-r--r--gas/write.c59
30 files changed, 812 insertions, 111 deletions
diff --git a/gas/ChangeLog b/gas/ChangeLog
index 22dc882..bb827aa 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,46 @@
+2018-02-17 H.J. Lu <hongjiu.lu@intel.com>
+
+ * NEWS: Mention .nop directive.
+ * as.h (_relax_state): Add rs_space_nop and rs_fill_nop.
+ * read.c (potable): Add .nop.
+ (s_nop): New function.
+ * read.h (s_nop): New prototype.
+ * write.c (cvt_frag_to_fill): Handle rs_space_nop and
+ rs_fill_nop.
+ (md_generate_nops): New function.
+ (relax_segment): Likewise.
+ (write_contents): Use md_generate_nops for rs_fill_nop.
+ * config/tc-i386.c (alt64_11): New.
+ (alt64_patt): Likewise.
+ (md_convert_frag): Handle rs_space_nop.
+ (i386_output_nops): New function.
+ (i386_generate_nops): Likewise.
+ (i386_align_code): Call i386_output_nops.
+ * config/tc-i386.h (i386_generate_nops): New.
+ (md_generate_nops): Likewise.
+ * doc/as.texinfo: Document .nop directive.
+ * testsuite/gas/i386/i386.exp: Run .nop directive tests.
+ * testsuite/gas/i386/nop-1.d: New file.
+ * testsuite/gas/i386/nop-1.s: Likewise.
+ * testsuite/gas/i386/nop-2.d: Likewise.
+ * testsuite/gas/i386/nop-2.s: Likewise.
+ * testsuite/gas/i386/nop-3.d: Likewise.
+ * testsuite/gas/i386/nop-3.s: Likewise.
+ * testsuite/gas/i386/nop-4.d: Likewise.
+ * testsuite/gas/i386/nop-4.s: Likewise.
+ * testsuite/gas/i386/nop-5.d: Likewise.
+ * testsuite/gas/i386/nop-5.s: Likewise.
+ * testsuite/gas/i386/nop-6.d: Likewise.
+ * testsuite/gas/i386/nop-6.s: Likewise.
+ * testsuite/gas/i386/nop-bad-1.l: Likewise.
+ * testsuite/gas/i386/nop-bad-1.s: Likewise.
+ * testsuite/gas/i386/x86-64-nop-1.d: Likewise.
+ * testsuite/gas/i386/x86-64-nop-2.d: Likewise.
+ * testsuite/gas/i386/x86-64-nop-3.d: Likewise.
+ * testsuite/gas/i386/x86-64-nop-4.d: Likewise.
+ * testsuite/gas/i386/x86-64-nop-5.d: Likewise.
+ * testsuite/gas/i386/x86-64-nop-6.d: Likewise.
+
2018-02-15 Tamar Christina <tamar.christina@arm.com>
* config/tc-arm.c (cpu_arch_ver): Renumber ARM_ARCH_V8_4A.
diff --git a/gas/NEWS b/gas/NEWS
index a591a7b..27ee306 100644
--- a/gas/NEWS
+++ b/gas/NEWS
@@ -1,5 +1,8 @@
-*- text -*-
+* Add support for .nop directive. It is currently supported only for
+ x86 targets.
+
Changes in 2.30:
* Add support for loaction views in DWARF debug line information.
diff --git a/gas/as.h b/gas/as.h
index c33353a..d75ff42 100644
--- a/gas/as.h
+++ b/gas/as.h
@@ -279,6 +279,16 @@ enum _relax_state
1 variable char: fill character */
rs_space,
+ /* .nop directive with expression operand that needs to be computed
+ later. Similar to rs_space, but different. It fills with no-op
+ instructions.
+ fr_symbol: operand
+ 1 constant byte: no-op fill control byte. */
+ rs_space_nop,
+
+ /* Similar to rs_fill. It is used to implement .nop directive . */
+ rs_fill_nop,
+
/* A DWARF leb128 value; only ELF uses this. The subtype is 0 for
unsigned, 1 for signed. */
rs_leb128,
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 1a5be1b..c67ea1f 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -1146,105 +1146,174 @@ static struct hash_control *op_hash;
/* Hash table for register lookup. */
static struct hash_control *reg_hash;
-void
-i386_align_code (fragS *fragP, int count)
-{
/* Various efficient no-op patterns for aligning code labels.
Note: Don't try to assemble the instructions in the comments.
0L and 0w are not legal. */
- static const unsigned char f32_1[] =
- {0x90}; /* nop */
- static const unsigned char f32_2[] =
- {0x66,0x90}; /* xchg %ax,%ax */
- static const unsigned char f32_3[] =
- {0x8d,0x76,0x00}; /* leal 0(%esi),%esi */
- static const unsigned char f32_4[] =
- {0x8d,0x74,0x26,0x00}; /* leal 0(%esi,1),%esi */
- static const unsigned char f32_5[] =
- {0x90, /* nop */
- 0x8d,0x74,0x26,0x00}; /* leal 0(%esi,1),%esi */
- static const unsigned char f32_6[] =
- {0x8d,0xb6,0x00,0x00,0x00,0x00}; /* leal 0L(%esi),%esi */
- static const unsigned char f32_7[] =
- {0x8d,0xb4,0x26,0x00,0x00,0x00,0x00}; /* leal 0L(%esi,1),%esi */
- static const unsigned char f32_8[] =
- {0x90, /* nop */
- 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00}; /* leal 0L(%esi,1),%esi */
- static const unsigned char f32_9[] =
- {0x89,0xf6, /* movl %esi,%esi */
- 0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
- static const unsigned char f32_10[] =
- {0x8d,0x76,0x00, /* leal 0(%esi),%esi */
- 0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
- static const unsigned char f32_11[] =
- {0x8d,0x74,0x26,0x00, /* leal 0(%esi,1),%esi */
- 0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
- static const unsigned char f32_12[] =
- {0x8d,0xb6,0x00,0x00,0x00,0x00, /* leal 0L(%esi),%esi */
- 0x8d,0xbf,0x00,0x00,0x00,0x00}; /* leal 0L(%edi),%edi */
- static const unsigned char f32_13[] =
- {0x8d,0xb6,0x00,0x00,0x00,0x00, /* leal 0L(%esi),%esi */
- 0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
- static const unsigned char f32_14[] =
- {0x8d,0xb4,0x26,0x00,0x00,0x00,0x00, /* leal 0L(%esi,1),%esi */
- 0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
- static const unsigned char f16_3[] =
- {0x8d,0x74,0x00}; /* lea 0(%esi),%esi */
- static const unsigned char f16_4[] =
- {0x8d,0xb4,0x00,0x00}; /* lea 0w(%si),%si */
- static const unsigned char f16_5[] =
- {0x90, /* nop */
- 0x8d,0xb4,0x00,0x00}; /* lea 0w(%si),%si */
- static const unsigned char f16_6[] =
- {0x89,0xf6, /* mov %si,%si */
- 0x8d,0xbd,0x00,0x00}; /* lea 0w(%di),%di */
- static const unsigned char f16_7[] =
- {0x8d,0x74,0x00, /* lea 0(%si),%si */
- 0x8d,0xbd,0x00,0x00}; /* lea 0w(%di),%di */
- static const unsigned char f16_8[] =
- {0x8d,0xb4,0x00,0x00, /* lea 0w(%si),%si */
- 0x8d,0xbd,0x00,0x00}; /* lea 0w(%di),%di */
- static const unsigned char jump_31[] =
- {0xeb,0x1d,0x90,0x90,0x90,0x90,0x90, /* jmp .+31; lotsa nops */
- 0x90,0x90,0x90,0x90,0x90,0x90,0x90,0x90,
- 0x90,0x90,0x90,0x90,0x90,0x90,0x90,0x90,
- 0x90,0x90,0x90,0x90,0x90,0x90,0x90,0x90};
- static const unsigned char *const f32_patt[] = {
- f32_1, f32_2, f32_3, f32_4, f32_5, f32_6, f32_7, f32_8,
- f32_9, f32_10, f32_11, f32_12, f32_13, f32_14
- };
- static const unsigned char *const f16_patt[] = {
- f32_1, f32_2, f16_3, f16_4, f16_5, f16_6, f16_7, f16_8
- };
- /* nopl (%[re]ax) */
- static const unsigned char alt_3[] =
- {0x0f,0x1f,0x00};
- /* nopl 0(%[re]ax) */
- static const unsigned char alt_4[] =
- {0x0f,0x1f,0x40,0x00};
- /* nopl 0(%[re]ax,%[re]ax,1) */
- static const unsigned char alt_5[] =
- {0x0f,0x1f,0x44,0x00,0x00};
- /* nopw 0(%[re]ax,%[re]ax,1) */
- static const unsigned char alt_6[] =
- {0x66,0x0f,0x1f,0x44,0x00,0x00};
- /* nopl 0L(%[re]ax) */
- static const unsigned char alt_7[] =
- {0x0f,0x1f,0x80,0x00,0x00,0x00,0x00};
- /* nopl 0L(%[re]ax,%[re]ax,1) */
- static const unsigned char alt_8[] =
- {0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
- /* nopw 0L(%[re]ax,%[re]ax,1) */
- static const unsigned char alt_9[] =
- {0x66,0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
- /* nopw %cs:0L(%[re]ax,%[re]ax,1) */
- static const unsigned char alt_10[] =
- {0x66,0x2e,0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
- static const unsigned char *const alt_patt[] = {
- f32_1, f32_2, alt_3, alt_4, alt_5, alt_6, alt_7, alt_8,
- alt_9, alt_10
- };
+static const unsigned char f32_1[] =
+ {0x90}; /* nop */
+static const unsigned char f32_2[] =
+ {0x66,0x90}; /* xchg %ax,%ax */
+static const unsigned char f32_3[] =
+ {0x8d,0x76,0x00}; /* leal 0(%esi),%esi */
+static const unsigned char f32_4[] =
+ {0x8d,0x74,0x26,0x00}; /* leal 0(%esi,1),%esi */
+static const unsigned char f32_5[] =
+ {0x90, /* nop */
+ 0x8d,0x74,0x26,0x00}; /* leal 0(%esi,1),%esi */
+static const unsigned char f32_6[] =
+ {0x8d,0xb6,0x00,0x00,0x00,0x00}; /* leal 0L(%esi),%esi */
+static const unsigned char f32_7[] =
+ {0x8d,0xb4,0x26,0x00,0x00,0x00,0x00}; /* leal 0L(%esi,1),%esi */
+static const unsigned char f32_8[] =
+ {0x90, /* nop */
+ 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00}; /* leal 0L(%esi,1),%esi */
+static const unsigned char f32_9[] =
+ {0x89,0xf6, /* movl %esi,%esi */
+ 0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
+static const unsigned char f32_10[] =
+ {0x8d,0x76,0x00, /* leal 0(%esi),%esi */
+ 0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
+static const unsigned char f32_11[] =
+ {0x8d,0x74,0x26,0x00, /* leal 0(%esi,1),%esi */
+ 0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
+static const unsigned char f32_12[] =
+ {0x8d,0xb6,0x00,0x00,0x00,0x00, /* leal 0L(%esi),%esi */
+ 0x8d,0xbf,0x00,0x00,0x00,0x00}; /* leal 0L(%edi),%edi */
+static const unsigned char f32_13[] =
+ {0x8d,0xb6,0x00,0x00,0x00,0x00, /* leal 0L(%esi),%esi */
+ 0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
+static const unsigned char f32_14[] =
+ {0x8d,0xb4,0x26,0x00,0x00,0x00,0x00, /* leal 0L(%esi,1),%esi */
+ 0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
+static const unsigned char f16_3[] =
+ {0x8d,0x74,0x00}; /* lea 0(%esi),%esi */
+static const unsigned char f16_4[] =
+ {0x8d,0xb4,0x00,0x00}; /* lea 0w(%si),%si */
+static const unsigned char f16_5[] =
+ {0x90, /* nop */
+ 0x8d,0xb4,0x00,0x00}; /* lea 0w(%si),%si */
+static const unsigned char f16_6[] =
+ {0x89,0xf6, /* mov %si,%si */
+ 0x8d,0xbd,0x00,0x00}; /* lea 0w(%di),%di */
+static const unsigned char f16_7[] =
+ {0x8d,0x74,0x00, /* lea 0(%si),%si */
+ 0x8d,0xbd,0x00,0x00}; /* lea 0w(%di),%di */
+static const unsigned char f16_8[] =
+ {0x8d,0xb4,0x00,0x00, /* lea 0w(%si),%si */
+ 0x8d,0xbd,0x00,0x00}; /* lea 0w(%di),%di */
+static const unsigned char jump_31[] =
+ {0xeb,0x1d,0x90,0x90,0x90,0x90,0x90, /* jmp .+31; lotsa nops */
+ 0x90,0x90,0x90,0x90,0x90,0x90,0x90,0x90,
+ 0x90,0x90,0x90,0x90,0x90,0x90,0x90,0x90,
+ 0x90,0x90,0x90,0x90,0x90,0x90,0x90,0x90};
+/* 32-bit NOPs patterns. */
+static const unsigned char *const f32_patt[] = {
+ f32_1, f32_2, f32_3, f32_4, f32_5, f32_6, f32_7, f32_8,
+ f32_9, f32_10, f32_11, f32_12, f32_13, f32_14
+};
+/* 16-bit NOPs patterns. */
+static const unsigned char *const f16_patt[] = {
+ f32_1, f32_2, f16_3, f16_4, f16_5, f16_6, f16_7, f16_8
+};
+/* nopl (%[re]ax) */
+static const unsigned char alt_3[] =
+ {0x0f,0x1f,0x00};
+/* nopl 0(%[re]ax) */
+static const unsigned char alt_4[] =
+ {0x0f,0x1f,0x40,0x00};
+/* nopl 0(%[re]ax,%[re]ax,1) */
+static const unsigned char alt_5[] =
+ {0x0f,0x1f,0x44,0x00,0x00};
+/* nopw 0(%[re]ax,%[re]ax,1) */
+static const unsigned char alt_6[] =
+ {0x66,0x0f,0x1f,0x44,0x00,0x00};
+/* nopl 0L(%[re]ax) */
+static const unsigned char alt_7[] =
+ {0x0f,0x1f,0x80,0x00,0x00,0x00,0x00};
+/* nopl 0L(%[re]ax,%[re]ax,1) */
+static const unsigned char alt_8[] =
+ {0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
+/* nopw 0L(%[re]ax,%[re]ax,1) */
+static const unsigned char alt_9[] =
+ {0x66,0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
+/* nopw %cs:0L(%[re]ax,%[re]ax,1) */
+static const unsigned char alt_10[] =
+ {0x66,0x2e,0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
+/* 32-bit and 64-bit NOPs patterns. */
+static const unsigned char *const alt_patt[] = {
+ f32_1, f32_2, alt_3, alt_4, alt_5, alt_6, alt_7, alt_8,
+ alt_9, alt_10
+};
+/* 64-bit only: nopw %cs:0L(%eax,%eax,1) */
+static const unsigned char alt64_11[] =
+ {0x67,0x66,0x2e,0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
+/* 64-bit NOPs patterns. */
+static const unsigned char *const alt64_patt[] = {
+ f32_1, f32_2, alt_3, alt_4, alt_5, alt_6, alt_7, alt_8,
+ alt_9, alt_10, alt64_11
+};
+
+/* Genenerate COUNT bytes of NOPs to WHERE from PATT with the maximum
+ size of a single NOP instruction MAX_SINGLE_NOP_SIZE. */
+static void
+i386_output_nops (char *where, const unsigned char *const *patt,
+ int count, int max_single_nop_size)
+
+{
+ while (count > max_single_nop_size)
+ {
+ count -= max_single_nop_size;
+ memcpy (where + count, patt[max_single_nop_size - 1],
+ max_single_nop_size);
+ }
+
+ if (count)
+ memcpy (where, patt[count - 1], count);
+}
+
+
+/* Genenerate COUNT bytes of NOPs to WHERE with the maximum size of a
+ single NOP instruction LIMIT. */
+
+void
+i386_generate_nops (fragS *f, char *where, offsetT count, int limit)
+{
+ /* Output NOPs for .nop directive. */
+ int max_single_nop_size;
+ const unsigned char *const *patt;
+
+ if (flag_code == CODE_16BIT)
+ {
+ patt = f16_patt;
+ max_single_nop_size = sizeof (f16_patt) / sizeof (f16_patt[0]);
+ }
+ else if (flag_code == CODE_64BIT)
+ {
+ patt = alt64_patt;
+ max_single_nop_size = sizeof (alt64_patt) / sizeof (alt64_patt[0]);
+ }
+ else
+ {
+ patt = alt_patt;
+ max_single_nop_size = sizeof (alt_patt) / sizeof (alt_patt[0]);
+ }
+ if (limit == 0)
+ limit = max_single_nop_size;
+ else if (limit > max_single_nop_size)
+ {
+ as_bad_where (f->fr_file, f->fr_line,
+ _("invalide single nop size: %d (expect within [0, %d])"),
+ limit, max_single_nop_size);
+ return;
+ }
+
+ i386_output_nops (where, patt, count, limit);
+}
+
+void
+i386_align_code (fragS *fragP, int count)
+{
/* Only align for at least a positive non-zero boundary. */
if (count <= 0 || count > MAX_MEM_FOR_RS_ALIGN_CODE)
return;
@@ -1397,17 +1466,8 @@ i386_align_code (fragS *fragP, int count)
/* Maximum length of an instruction is 10 byte. If the
padding is greater than 10 bytes and we don't use jump,
we have to break it into smaller pieces. */
- int padding = count;
- while (padding > 10)
- {
- padding -= 10;
- memcpy (fragP->fr_literal + fragP->fr_fix + padding,
- patt [9], 10);
- }
-
- if (padding)
- memcpy (fragP->fr_literal + fragP->fr_fix,
- patt [padding - 1], padding);
+ i386_output_nops (fragP->fr_literal + fragP->fr_fix,
+ patt, count, 10);
}
}
fragP->fr_var = count;
diff --git a/gas/config/tc-i386.h b/gas/config/tc-i386.h
index 6e4f440..1250bc2 100644
--- a/gas/config/tc-i386.h
+++ b/gas/config/tc-i386.h
@@ -281,6 +281,11 @@ extern void sco_id (void);
#define WORKING_DOT_WORD 1
+/* How to generate NOPs for .nop direct directive. */
+extern void i386_generate_nops (fragS *, char *, offsetT, int);
+#define md_generate_nops(frag, where, amount, control) \
+ i386_generate_nops ((frag), (where), (amount), (control))
+
/* We want .cfi_* pseudo-ops for generating unwind info. */
#define TARGET_USE_CFIPOP 1
diff --git a/gas/doc/as.texinfo b/gas/doc/as.texinfo
index f4e0fdd..3084bcb 100644
--- a/gas/doc/as.texinfo
+++ b/gas/doc/as.texinfo
@@ -4479,6 +4479,7 @@ Some machine configurations provide additional directives.
* MRI:: @code{.mri @var{val}}
* Noaltmacro:: @code{.noaltmacro}
* Nolist:: @code{.nolist}
+* Nop:: @code{.nop @var{size}[, @var{control}]}
* Octa:: @code{.octa @var{bignums}}
* Offset:: @code{.offset @var{loc}}
* Org:: @code{.org @var{new-lc}, @var{fill}}
@@ -6101,6 +6102,23 @@ internal counter (which is zero initially). @code{.list} increments the
counter, and @code{.nolist} decrements it. Assembly listings are
generated whenever the counter is greater than zero.
+@node Nop
+@section @code{.nop @var{size}[, @var{control}]}
+
+@cindex @code{nop} directive
+@cindex filling memory with no-op instructions
+This directive emits @var{size} bytes filled with no-op instructions.
+@var{size} is absolute expression, which must be a positve value.
+@var{control} controls how no-op instructions should be generated. If
+the comma and @var{control} are omitted, @var{control} is assumed to be
+zero.
+
+Note: For Intel 80386 and AMD x86-64 targets, @var{control} specifies
+the size limit of a no-op instruction. The valid values of @var{control}
+are between 0 and 8 for 16-bit mode, between 0 and 10 for 32-bit mode,
+between 0 and 11 for 64-bit mode. When 0 is used, the no-op instruction
+size limit is set to the maximum supported size.
+
@node Octa
@section @code{.octa @var{bignums}}
diff --git a/gas/read.c b/gas/read.c
index 7bf52f1..9ab88f8 100644
--- a/gas/read.c
+++ b/gas/read.c
@@ -442,6 +442,7 @@ static const pseudo_typeS potable[] = {
/* size */
{"space", s_space, 0},
{"skip", s_space, 0},
+ {"nop", s_nop, 0},
{"sleb128", s_leb128, 1},
{"spc", s_ignore, 0},
{"stabd", s_stab, 'd'},
@@ -3508,6 +3509,58 @@ s_space (int mult)
mri_comment_end (stop, stopc);
}
+void
+s_nop (int ignore ATTRIBUTE_UNUSED)
+{
+ expressionS exp;
+ expressionS val;
+
+#ifdef md_flush_pending_output
+ md_flush_pending_output ();
+#endif
+
+#ifdef md_cons_align
+ md_cons_align (1);
+#endif
+
+ expression (&exp);
+
+ if (*input_line_pointer == ',')
+ {
+ ++input_line_pointer;
+ expression (&val);
+ }
+ else
+ {
+ val.X_op = O_constant;
+ val.X_add_number = 0;
+ }
+
+ if (val.X_op == O_constant)
+ {
+ if (val.X_add_number < 0)
+ {
+ as_warn (_("negative nop control byte, ignored"));
+ val.X_add_number = 0;
+ }
+
+ if (!need_pass_2)
+ {
+ /* Store the no-op instruction control byte in the first byte
+ of frag. */
+ char *p;
+ symbolS *sym = make_expr_symbol (&exp);
+ p = frag_var (rs_space_nop, 1, 1, (relax_substateT) 0,
+ sym, (offsetT) 0, (char *) 0);
+ *p = val.X_add_number;
+ }
+ }
+ else
+ as_bad (_("unsupported variable nop control in .nop directive"));
+
+ demand_empty_rest_of_line ();
+}
+
/* This is like s_space, but the value is a floating point number with
the given precision. This is for the MRI dcb.s pseudo-op and
friends. */
diff --git a/gas/read.h b/gas/read.h
index eebdc4e..3f0927b 100644
--- a/gas/read.h
+++ b/gas/read.h
@@ -206,6 +206,7 @@ extern void s_purgem (int);
extern void s_rept (int);
extern void s_set (int);
extern void s_space (int mult);
+extern void s_nop (int);
extern void s_stab (int what);
extern void s_struct (int);
extern void s_text (int);
diff --git a/gas/testsuite/gas/i386/i386.exp b/gas/testsuite/gas/i386/i386.exp
index a21ef84..0ca49ea 100644
--- a/gas/testsuite/gas/i386/i386.exp
+++ b/gas/testsuite/gas/i386/i386.exp
@@ -431,6 +431,8 @@ if [expr ([istarget "i*86-*-*"] || [istarget "x86_64-*-*"]) && [gas_32_check]]
run_dump_test "align-1a"
run_dump_test "align-1b"
run_list_test "inval-pseudo" "-al"
+ run_dump_test "nop-1"
+ run_dump_test "nop-2"
# These tests require support for 8 and 16 bit relocs,
# so we only run them for ELF and COFF targets.
@@ -494,6 +496,10 @@ if [expr ([istarget "i*86-*-*"] || [istarget "x86_64-*-*"]) && [gas_32_check]]
run_dump_test "got-no-relax"
run_dump_test "addend"
+ run_dump_test "nop-3"
+ run_dump_test "nop-4"
+ run_dump_test "nop-5"
+ run_dump_test "nop-6"
if { [gas_64_check] } then {
run_dump_test "att-regs"
@@ -538,6 +544,7 @@ if [expr [istarget "i*86-*-*"] || [istarget "x86_64-*-*"]] then {
run_list_test "space1" "-al"
run_dump_test rept
run_dump_test pr19498
+ run_list_test "nop-bad-1" ""
if [is_elf_format] then {
run_list_test_stdin "list-1" "-al"
run_list_test_stdin "list-2" "-al"
@@ -904,6 +911,8 @@ if [expr ([istarget "i*86-*-*"] || [istarget "x86_64-*-*"]) && [gas_64_check]] t
run_list_test "x86-64-notrackbad" "-al"
run_dump_test "x86-64-movd"
run_dump_test "x86-64-movd-intel"
+ run_dump_test "x86-64-nop-1"
+ run_dump_test "x86-64-nop-2"
if { ![istarget "*-*-aix*"]
&& ![istarget "*-*-beos*"]
@@ -961,6 +970,10 @@ if [expr ([istarget "i*86-*-*"] || [istarget "x86_64-*-*"]) && [gas_64_check]] t
run_dump_test "x86-64-gotpcrel-no-relax"
run_dump_test "x86-64-addend"
+ run_dump_test "x86-64-nop-3"
+ run_dump_test "x86-64-nop-4"
+ run_dump_test "x86-64-nop-5"
+ run_dump_test "x86-64-nop-6"
}
set ASFLAGS "$old_ASFLAGS"
diff --git a/gas/testsuite/gas/i386/nop-1.d b/gas/testsuite/gas/i386/nop-1.d
new file mode 100644
index 0000000..46422c8
--- /dev/null
+++ b/gas/testsuite/gas/i386/nop-1.d
@@ -0,0 +1,31 @@
+#objdump: -drw
+#name: i386 .nop 1
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <single>:
+ +[a-f0-9]+: 90 nop
+
+0+1 <pseudo_1>:
+ +[a-f0-9]+: 90 nop
+
+0+2 <pseudo_8>:
+ +[a-f0-9]+: 0f 1f 84 00 00 00 00 00 nopl 0x0\(%eax,%eax,1\)
+
+0+a <pseudo_8_4>:
+ +[a-f0-9]+: 0f 1f 40 00 nopl 0x0\(%eax\)
+ +[a-f0-9]+: 0f 1f 40 00 nopl 0x0\(%eax\)
+
+0+12 <pseudo_20>:
+ +[a-f0-9]+: 66 2e 0f 1f 84 00 00 00 00 00 nopw %cs:0x0\(%eax,%eax,1\)
+ +[a-f0-9]+: 66 2e 0f 1f 84 00 00 00 00 00 nopw %cs:0x0\(%eax,%eax,1\)
+
+0+26 <pseudo_30>:
+ +[a-f0-9]+: 66 2e 0f 1f 84 00 00 00 00 00 nopw %cs:0x0\(%eax,%eax,1\)
+ +[a-f0-9]+: 66 2e 0f 1f 84 00 00 00 00 00 nopw %cs:0x0\(%eax,%eax,1\)
+ +[a-f0-9]+: 66 2e 0f 1f 84 00 00 00 00 00 nopw %cs:0x0\(%eax,%eax,1\)
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+#pass
diff --git a/gas/testsuite/gas/i386/nop-1.s b/gas/testsuite/gas/i386/nop-1.s
new file mode 100644
index 0000000..891783d
--- /dev/null
+++ b/gas/testsuite/gas/i386/nop-1.s
@@ -0,0 +1,21 @@
+ .text
+single:
+ .nop 0
+ nop
+
+pseudo_1:
+ .nop 1
+
+pseudo_8:
+ .nop 8
+
+pseudo_8_4:
+ .nop 8, 4
+
+pseudo_20:
+ .nop 20
+
+pseudo_30:
+ .nop 30
+
+ xor %eax, %eax
diff --git a/gas/testsuite/gas/i386/nop-2.d b/gas/testsuite/gas/i386/nop-2.d
new file mode 100644
index 0000000..332b990
--- /dev/null
+++ b/gas/testsuite/gas/i386/nop-2.d
@@ -0,0 +1,40 @@
+#objdump: -drw -Mi8086
+#name: i386 .nop 2
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <single>:
+ +[a-f0-9]+: 90 nop
+
+0+1 <pseudo_1>:
+ +[a-f0-9]+: 90 nop
+
+0+2 <pseudo_8>:
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d bd 00 00 lea 0x0\(%di\),%di
+
+0+a <pseudo_8_4>:
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+
+0+12 <pseudo_20>:
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d bd 00 00 lea 0x0\(%di\),%di
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d bd 00 00 lea 0x0\(%di\),%di
+
+0+26 <pseudo_30>:
+ +[a-f0-9]+: 89 f6 mov %si,%si
+ +[a-f0-9]+: 8d bd 00 00 lea 0x0\(%di\),%di
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d bd 00 00 lea 0x0\(%di\),%di
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d bd 00 00 lea 0x0\(%di\),%di
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d bd 00 00 lea 0x0\(%di\),%di
+ +[a-f0-9]+: 66 31 c0 xor %eax,%eax
+#pass
diff --git a/gas/testsuite/gas/i386/nop-2.s b/gas/testsuite/gas/i386/nop-2.s
new file mode 100644
index 0000000..2b71b97
--- /dev/null
+++ b/gas/testsuite/gas/i386/nop-2.s
@@ -0,0 +1,22 @@
+ .text
+ .code16
+single:
+ .nop 0
+ nop
+
+pseudo_1:
+ .nop 1
+
+pseudo_8:
+ .nop 8
+
+pseudo_8_4:
+ .nop 8, 4
+
+pseudo_20:
+ .nop 20
+
+pseudo_30:
+ .nop 30
+
+ xor %eax, %eax
diff --git a/gas/testsuite/gas/i386/nop-3.d b/gas/testsuite/gas/i386/nop-3.d
new file mode 100644
index 0000000..bebd24b
--- /dev/null
+++ b/gas/testsuite/gas/i386/nop-3.d
@@ -0,0 +1,20 @@
+#objdump: -drw
+#name: i386 .nop 3
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <_start>:
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+ +[a-f0-9]+: 85 c0 test %eax,%eax
+ +[a-f0-9]+: 0f 1f 00 nopl \(%eax\)
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+
+Disassembly of section .altinstr_replacement:
+
+0+ <.altinstr_replacement>:
+ +[a-f0-9]+: e9 fc ff ff ff jmp 1 <.altinstr_replacement\+0x1> 1: (R_386_PC)?(DISP)?32 foo
+#pass
diff --git a/gas/testsuite/gas/i386/nop-3.s b/gas/testsuite/gas/i386/nop-3.s
new file mode 100644
index 0000000..57370ff
--- /dev/null
+++ b/gas/testsuite/gas/i386/nop-3.s
@@ -0,0 +1,15 @@
+ .text
+_start:
+ xor %eax, %eax
+140:
+ testl %eax, %eax
+141:
+ .nop -(((144f-143f)-(141b-140b)) > 0)*((144f-143f)-(141b-140b)),7
+142:
+ xor %eax, %eax
+ .pushsection .altinstr_replacement,"ax"
+143:
+ jmp foo
+144:
+ .popsection
+ xor %eax, %eax
diff --git a/gas/testsuite/gas/i386/nop-4.d b/gas/testsuite/gas/i386/nop-4.d
new file mode 100644
index 0000000..99ddcd3
--- /dev/null
+++ b/gas/testsuite/gas/i386/nop-4.d
@@ -0,0 +1,23 @@
+#objdump: -drw
+#name: i386 .nop 4
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <_start>:
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+ +[a-f0-9]+: 85 c0 test %eax,%eax
+ +[a-f0-9]+: 66 0f 1f 84 00 00 00 00 00 nopw 0x0\(%eax,%eax,1\)
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+
+Disassembly of section .altinstr_replacement:
+
+0+ <.altinstr_replacement>:
+ +[a-f0-9]+: 89 c0 mov %eax,%eax
+ +[a-f0-9]+: 89 c0 mov %eax,%eax
+ +[a-f0-9]+: 89 c0 mov %eax,%eax
+ +[a-f0-9]+: e9 fc ff ff ff jmp 7 <.altinstr_replacement\+0x7> 7: (R_386_PC)?(DISP)?32 foo
+#pass
diff --git a/gas/testsuite/gas/i386/nop-4.s b/gas/testsuite/gas/i386/nop-4.s
new file mode 100644
index 0000000..f7aa111
--- /dev/null
+++ b/gas/testsuite/gas/i386/nop-4.s
@@ -0,0 +1,18 @@
+ .text
+_start:
+ xor %eax, %eax
+140:
+ testl %eax, %eax
+141:
+ .nop -(((144f-143f)-(141b-140b)) > 0)*((144f-143f)-(141b-140b))
+142:
+ xor %eax, %eax
+ .pushsection .altinstr_replacement,"ax"
+143:
+ mov %eax, %eax
+ mov %eax, %eax
+ mov %eax, %eax
+ jmp foo
+144:
+ .popsection
+ xor %eax, %eax
diff --git a/gas/testsuite/gas/i386/nop-5.d b/gas/testsuite/gas/i386/nop-5.d
new file mode 100644
index 0000000..aab4258
--- /dev/null
+++ b/gas/testsuite/gas/i386/nop-5.d
@@ -0,0 +1,25 @@
+#objdump: -drw
+#name: i386 .nop 5
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <_start>:
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+ +[a-f0-9]+: 85 c0 test %eax,%eax
+ +[a-f0-9]+: 0f 1f 44 00 00 nopl 0x0\(%eax,%eax,1\)
+ +[a-f0-9]+: 66 0f 1f 44 00 00 nopw 0x0\(%eax,%eax,1\)
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+
+Disassembly of section .altinstr_replacement:
+
+0+ <.altinstr_replacement>:
+ +[a-f0-9]+: 89 c0 mov %eax,%eax
+ +[a-f0-9]+: 89 c0 mov %eax,%eax
+ +[a-f0-9]+: 89 c0 mov %eax,%eax
+ +[a-f0-9]+: 89 c0 mov %eax,%eax
+ +[a-f0-9]+: e9 fc ff ff ff jmp 9 <.altinstr_replacement\+0x9> 9: (R_386_PC)?(DISP)?32 foo
+#pass
diff --git a/gas/testsuite/gas/i386/nop-5.s b/gas/testsuite/gas/i386/nop-5.s
new file mode 100644
index 0000000..4f563ce
--- /dev/null
+++ b/gas/testsuite/gas/i386/nop-5.s
@@ -0,0 +1,19 @@
+ .text
+_start:
+ xor %eax, %eax
+140:
+ testl %eax, %eax
+141:
+ .nop -(((144f-143f)-(141b-140b)) > 0)*((144f-143f)-(141b-140b)),6
+142:
+ xor %eax, %eax
+ .pushsection .altinstr_replacement,"ax"
+143:
+ mov %eax, %eax
+ mov %eax, %eax
+ mov %eax, %eax
+ mov %eax, %eax
+ jmp foo
+144:
+ .popsection
+ xor %eax, %eax
diff --git a/gas/testsuite/gas/i386/nop-6.d b/gas/testsuite/gas/i386/nop-6.d
new file mode 100644
index 0000000..93ee8de
--- /dev/null
+++ b/gas/testsuite/gas/i386/nop-6.d
@@ -0,0 +1,17 @@
+#objdump: -drw
+#name: i386 .nop 6
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <_start>:
+ +[a-f0-9]+: 0f 1f 40 00 nopl 0x0\(%eax\)
+
+Disassembly of section .altinstr_replacement:
+
+0+ <.altinstr_replacement>:
+ +[a-f0-9]+: 75 fe jne 0 <_start>
+ +[a-f0-9]+: 89 c4 mov %eax,%esp
+#pass
diff --git a/gas/testsuite/gas/i386/nop-6.s b/gas/testsuite/gas/i386/nop-6.s
new file mode 100644
index 0000000..c7b1e2c
--- /dev/null
+++ b/gas/testsuite/gas/i386/nop-6.s
@@ -0,0 +1,25 @@
+.macro mknops nr_bytes
+ .nop \nr_bytes, 9
+.endm
+
+.macro ALTERNATIVE
+.L\@_orig_s:
+.L\@_orig_e:
+ mknops (-(((.L\@_repl_e\()1 - .L\@_repl_s\()1) - (.L\@_orig_e - .L\@_orig_s)) > 0) * ((.L\@_repl_e\()1 - .L\@_repl_s\()1) - (.L\@_orig_e - .L\@_orig_s)))
+.L\@_orig_p:
+
+ .section .discard, "a", @progbits
+ .byte (.L\@_orig_p - .L\@_orig_s)
+ .byte 0xff + (.L\@_repl_e\()1 - .L\@_repl_s\()1) - (.L\@_orig_p - .L\@_orig_s)
+
+ .section .altinstr_replacement, "ax", @progbits
+.L\@_repl_s\()1:
+.L\@_fill_rsb_loop:
+ jnz .L\@_fill_rsb_loop
+ mov %eax, %esp
+.L\@_repl_e\()1:
+.endm
+
+ .text
+_start:
+ALTERNATIVE
diff --git a/gas/testsuite/gas/i386/nop-bad-1.l b/gas/testsuite/gas/i386/nop-bad-1.l
new file mode 100644
index 0000000..34be496
--- /dev/null
+++ b/gas/testsuite/gas/i386/nop-bad-1.l
@@ -0,0 +1,4 @@
+.*: Assembler messages:
+.*:2: Warning: negative nop control byte, ignored
+.*:4: Warning: \.space, \.nop or \.fill with negative value, ignored
+.*:3: Error: invalide single nop size: 20 \(expect within \[0, [0-9]+\]\)
diff --git a/gas/testsuite/gas/i386/nop-bad-1.s b/gas/testsuite/gas/i386/nop-bad-1.s
new file mode 100644
index 0000000..53cc7d5
--- /dev/null
+++ b/gas/testsuite/gas/i386/nop-bad-1.s
@@ -0,0 +1,4 @@
+ .text
+ .nop 100, -2
+ .nop 100, 20
+ .nop -1
diff --git a/gas/testsuite/gas/i386/x86-64-nop-1.d b/gas/testsuite/gas/i386/x86-64-nop-1.d
new file mode 100644
index 0000000..f3edc7d
--- /dev/null
+++ b/gas/testsuite/gas/i386/x86-64-nop-1.d
@@ -0,0 +1,32 @@
+#source: nop-1.s
+#objdump: -drw
+#name: x86-64 .nop 1
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <single>:
+ +[a-f0-9]+: 90 nop
+
+0+1 <pseudo_1>:
+ +[a-f0-9]+: 90 nop
+
+0+2 <pseudo_8>:
+ +[a-f0-9]+: 0f 1f 84 00 00 00 00 00 nopl 0x0\(%rax,%rax,1\)
+
+0+a <pseudo_8_4>:
+ +[a-f0-9]+: 0f 1f 40 00 nopl 0x0\(%rax\)
+ +[a-f0-9]+: 0f 1f 40 00 nopl 0x0\(%rax\)
+
+0+12 <pseudo_20>:
+ +[a-f0-9]+: 66 0f 1f 84 00 00 00 00 00 nopw 0x0\(%rax,%rax,1\)
+ +[a-f0-9]+: 67 66 2e 0f 1f 84 00 00 00 00 00 nopw %cs:0x0\(%eax,%eax,1\)
+
+0+26 <pseudo_30>:
+ +[a-f0-9]+: 0f 1f 84 00 00 00 00 00 nopl 0x0\(%rax,%rax,1\)
+ +[a-f0-9]+: 67 66 2e 0f 1f 84 00 00 00 00 00 nopw %cs:0x0\(%eax,%eax,1\)
+ +[a-f0-9]+: 67 66 2e 0f 1f 84 00 00 00 00 00 nopw %cs:0x0\(%eax,%eax,1\)
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+#pass
diff --git a/gas/testsuite/gas/i386/x86-64-nop-2.d b/gas/testsuite/gas/i386/x86-64-nop-2.d
new file mode 100644
index 0000000..e894d2c
--- /dev/null
+++ b/gas/testsuite/gas/i386/x86-64-nop-2.d
@@ -0,0 +1,41 @@
+#source: nop-2.s
+#objdump: -drw -Mi8086
+#name: x86-64 .nop 2
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <single>:
+ +[a-f0-9]+: 90 nop
+
+0+1 <pseudo_1>:
+ +[a-f0-9]+: 90 nop
+
+0+2 <pseudo_8>:
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d bd 00 00 lea 0x0\(%di\),%di
+
+0+a <pseudo_8_4>:
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+
+0+12 <pseudo_20>:
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d bd 00 00 lea 0x0\(%di\),%di
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d bd 00 00 lea 0x0\(%di\),%di
+
+0+26 <pseudo_30>:
+ +[a-f0-9]+: 89 f6 mov %si,%si
+ +[a-f0-9]+: 8d bd 00 00 lea 0x0\(%di\),%di
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d bd 00 00 lea 0x0\(%di\),%di
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d bd 00 00 lea 0x0\(%di\),%di
+ +[a-f0-9]+: 8d b4 00 00 lea 0x0\(%si\),%si
+ +[a-f0-9]+: 8d bd 00 00 lea 0x0\(%di\),%di
+ +[a-f0-9]+: 66 31 c0 xor %eax,%eax
+#pass
diff --git a/gas/testsuite/gas/i386/x86-64-nop-3.d b/gas/testsuite/gas/i386/x86-64-nop-3.d
new file mode 100644
index 0000000..b43239a
--- /dev/null
+++ b/gas/testsuite/gas/i386/x86-64-nop-3.d
@@ -0,0 +1,21 @@
+#source: nop-3.s
+#objdump: -drw
+#name: x86-64 .nop 3
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <_start>:
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+ +[a-f0-9]+: 85 c0 test %eax,%eax
+ +[a-f0-9]+: 0f 1f 00 nopl \(%rax\)
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+
+Disassembly of section .altinstr_replacement:
+
+0+ <.altinstr_replacement>:
+ +[a-f0-9]+: e9 00 00 00 00 jmpq 5 <_start\+0x5> 1: R_X86_64_PLT32 foo-0x4
+#pass
diff --git a/gas/testsuite/gas/i386/x86-64-nop-4.d b/gas/testsuite/gas/i386/x86-64-nop-4.d
new file mode 100644
index 0000000..a910171
--- /dev/null
+++ b/gas/testsuite/gas/i386/x86-64-nop-4.d
@@ -0,0 +1,24 @@
+#source: nop-4.s
+#objdump: -drw
+#name: x86-64 .nop 4
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <_start>:
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+ +[a-f0-9]+: 85 c0 test %eax,%eax
+ +[a-f0-9]+: 66 0f 1f 84 00 00 00 00 00 nopw 0x0\(%rax,%rax,1\)
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+
+Disassembly of section .altinstr_replacement:
+
+0+ <.altinstr_replacement>:
+ +[a-f0-9]+: 89 c0 mov %eax,%eax
+ +[a-f0-9]+: 89 c0 mov %eax,%eax
+ +[a-f0-9]+: 89 c0 mov %eax,%eax
+ +[a-f0-9]+: e9 00 00 00 00 jmpq b <_start\+0xb> 7: R_X86_64_PLT32 foo-0x4
+#pass
diff --git a/gas/testsuite/gas/i386/x86-64-nop-5.d b/gas/testsuite/gas/i386/x86-64-nop-5.d
new file mode 100644
index 0000000..57493cf
--- /dev/null
+++ b/gas/testsuite/gas/i386/x86-64-nop-5.d
@@ -0,0 +1,26 @@
+#source: nop-5.s
+#objdump: -drw
+#name: x86-64 .nop 5
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <_start>:
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+ +[a-f0-9]+: 85 c0 test %eax,%eax
+ +[a-f0-9]+: 0f 1f 44 00 00 nopl 0x0\(%rax,%rax,1\)
+ +[a-f0-9]+: 66 0f 1f 44 00 00 nopw 0x0\(%rax,%rax,1\)
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+ +[a-f0-9]+: 31 c0 xor %eax,%eax
+
+Disassembly of section .altinstr_replacement:
+
+0+ <.altinstr_replacement>:
+ +[a-f0-9]+: 89 c0 mov %eax,%eax
+ +[a-f0-9]+: 89 c0 mov %eax,%eax
+ +[a-f0-9]+: 89 c0 mov %eax,%eax
+ +[a-f0-9]+: 89 c0 mov %eax,%eax
+ +[a-f0-9]+: e9 00 00 00 00 jmpq d <_start\+0xd> 9: R_X86_64_PLT32 foo-0x4
+#pass
diff --git a/gas/testsuite/gas/i386/x86-64-nop-6.d b/gas/testsuite/gas/i386/x86-64-nop-6.d
new file mode 100644
index 0000000..520f590
--- /dev/null
+++ b/gas/testsuite/gas/i386/x86-64-nop-6.d
@@ -0,0 +1,18 @@
+#source: nop-6.s
+#objdump: -drw
+#name: x86-64 .nop 6
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <_start>:
+ +[a-f0-9]+: 0f 1f 40 00 nopl 0x0\(%rax\)
+
+Disassembly of section .altinstr_replacement:
+
+0+ <.altinstr_replacement>:
+ +[a-f0-9]+: 75 fe jne 0 <_start>
+ +[a-f0-9]+: 89 c4 mov %eax,%esp
+#pass
diff --git a/gas/write.c b/gas/write.c
index 2869660..9b14fda 100644
--- a/gas/write.c
+++ b/gas/write.c
@@ -435,6 +435,8 @@ cvt_frag_to_fill (segT sec ATTRIBUTE_UNUSED, fragS *fragP)
{
switch (fragP->fr_type)
{
+ case rs_space_nop:
+ goto skip_align;
case rs_align:
case rs_align_code:
case rs_align_test:
@@ -443,6 +445,7 @@ cvt_frag_to_fill (segT sec ATTRIBUTE_UNUSED, fragS *fragP)
#ifdef HANDLE_ALIGN
HANDLE_ALIGN (fragP);
#endif
+skip_align:
know (fragP->fr_next != NULL);
fragP->fr_offset = (fragP->fr_next->fr_address
- fragP->fr_address
@@ -450,14 +453,18 @@ cvt_frag_to_fill (segT sec ATTRIBUTE_UNUSED, fragS *fragP)
if (fragP->fr_offset < 0)
{
as_bad_where (fragP->fr_file, fragP->fr_line,
- _("attempt to .org/.space backwards? (%ld)"),
+ _("attempt to .org/.space/.nop backwards? (%ld)"),
(long) fragP->fr_offset);
fragP->fr_offset = 0;
}
- fragP->fr_type = rs_fill;
+ if (fragP->fr_type == rs_space_nop)
+ fragP->fr_type = rs_fill_nop;
+ else
+ fragP->fr_type = rs_fill;
break;
case rs_fill:
+ case rs_fill_nop:
break;
case rs_leb128:
@@ -1570,6 +1577,20 @@ compress_debug (bfd *abfd, asection *sec, void *xxx ATTRIBUTE_UNUSED)
}
}
+#ifndef md_generate_nops
+/* Genenerate COUNT bytes of no-op instructions to WHERE. A target
+ backend must override this with proper no-op instructions. */
+
+static void
+md_generate_nops (fragS *f ATTRIBUTE_UNUSED,
+ char *where ATTRIBUTE_UNUSED,
+ offsetT count ATTRIBUTE_UNUSED,
+ int control ATTRIBUTE_UNUSED)
+{
+ as_bad (_("unimplemented .nop directive"));
+}
+#endif
+
static void
write_contents (bfd *abfd ATTRIBUTE_UNUSED,
asection *sec,
@@ -1593,7 +1614,7 @@ write_contents (bfd *abfd ATTRIBUTE_UNUSED,
char *fill_literal;
offsetT count;
- gas_assert (f->fr_type == rs_fill);
+ gas_assert (f->fr_type == rs_fill || f->fr_type == rs_fill_nop);
if (f->fr_fix)
{
x = bfd_set_section_contents (stdoutput, sec,
@@ -1610,9 +1631,35 @@ write_contents (bfd *abfd ATTRIBUTE_UNUSED,
bfd_errmsg (bfd_get_error ()));
offset += f->fr_fix;
}
- fill_literal = f->fr_literal + f->fr_fix;
+
fill_size = f->fr_var;
count = f->fr_offset;
+ fill_literal = f->fr_literal + f->fr_fix;
+
+ if (f->fr_type == rs_fill_nop)
+ {
+ gas_assert (count >= 0 && fill_size == 1);
+ if (count > 0)
+ {
+ char *buf = xmalloc (count);
+ md_generate_nops (f, buf, count, *fill_literal);
+ x = bfd_set_section_contents
+ (stdoutput, sec, buf, (file_ptr) offset,
+ (bfd_size_type) count);
+ if (!x)
+ as_fatal (ngettext ("can't fill %ld byte "
+ "in section %s of %s: '%s'",
+ "can't fill %ld bytes "
+ "in section %s of %s: '%s'",
+ (long) count), (long) count,
+ sec->name, stdoutput->filename,
+ bfd_errmsg (bfd_get_error ()));
+ offset += count;
+ free (buf);
+ }
+ continue;
+ }
+
gas_assert (count >= 0);
if (fill_size && count)
{
@@ -2461,6 +2508,7 @@ relax_segment (struct frag *segment_frag_root, segT segment, int pass)
break;
case rs_space:
+ case rs_space_nop:
break;
case rs_machine_dependent:
@@ -2765,6 +2813,7 @@ relax_segment (struct frag *segment_frag_root, segT segment, int pass)
break;
case rs_space:
+ case rs_space_nop:
growth = 0;
if (symbolP)
{
@@ -2791,7 +2840,7 @@ relax_segment (struct frag *segment_frag_root, segT segment, int pass)
}
as_warn_where (fragP->fr_file, fragP->fr_line,
- _(".space or .fill with negative value, ignored"));
+ _(".space, .nop or .fill with negative value, ignored"));
fragP->fr_symbol = 0;
}
else