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authorJan Beulich <jbeulich@suse.com>2023-10-23 10:32:32 +0200
committerJan Beulich <jbeulich@suse.com>2023-10-23 10:32:32 +0200
commitcd75cd859e58ff7161871849c59f01e9df3cdbc3 (patch)
treedbf7d2d071c1a19c38553e42449ed44a96d6bc22
parent5e0729b655a2594c7b6750fb53f2f99750744ca2 (diff)
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x86: respect ".arch nonop" when selecting which NOPs to emit
Making GENERIC64 a special case was never correct; prior to the generalization of ".arch .no*" to cover all ISA extensions other processor families supporting long NOPs should have been covered as well. When introducing ".arch .nonops" (among others) it wasn't apparent that a hidden implication of .cpunop not being possible to separately turn off existed here. Seeing that the two large case label blocks in the 2nd switch() already had identical behavior, simply collapse all of the (useful) case labels into a single "default" one.
-rw-r--r--gas/config/tc-i386.c35
-rw-r--r--gas/config/tc-i386.h3
-rw-r--r--gas/testsuite/gas/i386/x86-64-nops-1a-core2.d5
-rw-r--r--gas/testsuite/gas/i386/x86-64-nops-1a-g64.d5
-rw-r--r--gas/testsuite/gas/i386/x86-64.exp2
5 files changed, 23 insertions, 27 deletions
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index b8df4e9..d936252 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -802,7 +802,7 @@ static const char *cpu_arch_name = NULL;
static char *cpu_sub_arch_name = NULL;
/* CPU feature flags. */
-static i386_cpu_flags cpu_arch_flags = CPU_UNKNOWN_FLAGS;
+i386_cpu_flags cpu_arch_flags = CPU_UNKNOWN_FLAGS;
/* If we have selected a cpu we are generating instructions for. */
static int cpu_arch_tune_set = 0;
@@ -1463,7 +1463,8 @@ i386_generate_nops (fragS *fragP, char *where, offsetT count, int limit)
patt = fragP->tc_frag_data.code == CODE_64BIT ? f64_patt : f32_patt;
if (fragP->tc_frag_data.isa == PROCESSOR_UNKNOWN)
{
- /* PROCESSOR_UNKNOWN means that all ISAs may be used. */
+ /* PROCESSOR_UNKNOWN means that all ISAs may be used, unless
+ explicitly disabled. */
switch (fragP->tc_frag_data.tune)
{
case PROCESSOR_UNKNOWN:
@@ -1485,8 +1486,10 @@ i386_generate_nops (fragS *fragP, char *where, offsetT count, int limit)
case PROCESSOR_BD:
case PROCESSOR_ZNVER:
case PROCESSOR_BT:
- patt = alt_patt;
+ if (fragP->tc_frag_data.cpunop)
+ patt = alt_patt;
break;
+
case PROCESSOR_I386:
case PROCESSOR_I486:
case PROCESSOR_PENTIUM:
@@ -1508,35 +1511,13 @@ i386_generate_nops (fragS *fragP, char *where, offsetT count, int limit)
abort ();
break;
- case PROCESSOR_I386:
- case PROCESSOR_I486:
- case PROCESSOR_PENTIUM:
- case PROCESSOR_IAMCU:
- case PROCESSOR_K6:
- case PROCESSOR_ATHLON:
- case PROCESSOR_K8:
- case PROCESSOR_AMDFAM10:
- case PROCESSOR_BD:
- case PROCESSOR_ZNVER:
- case PROCESSOR_BT:
- case PROCESSOR_GENERIC32:
+ default:
/* We use cpu_arch_isa_flags to check if we CAN optimize
with nops. */
if (fragP->tc_frag_data.isa_flags.bitfield.cpunop)
patt = alt_patt;
break;
- case PROCESSOR_PENTIUMPRO:
- case PROCESSOR_PENTIUM4:
- case PROCESSOR_NOCONA:
- case PROCESSOR_CORE:
- case PROCESSOR_CORE2:
- case PROCESSOR_COREI7:
- if (fragP->tc_frag_data.isa_flags.bitfield.cpunop)
- patt = alt_patt;
- break;
- case PROCESSOR_GENERIC64:
- patt = alt_patt;
- break;
+
case PROCESSOR_NONE:
abort ();
}
diff --git a/gas/config/tc-i386.h b/gas/config/tc-i386.h
index d49a0de..696e519 100644
--- a/gas/config/tc-i386.h
+++ b/gas/config/tc-i386.h
@@ -260,6 +260,7 @@ enum processor_type
PROCESSOR_NONE
};
+extern i386_cpu_flags cpu_arch_flags;
extern enum processor_type cpu_arch_tune;
extern enum processor_type cpu_arch_isa;
extern i386_cpu_flags cpu_arch_isa_flags;
@@ -295,6 +296,7 @@ struct i386_tc_frag_data
unsigned int mf_type : 3;
unsigned int classified : 1;
unsigned int branch_type : 3;
+ unsigned int cpunop : 1;
};
/* We need to emit the right NOP pattern in .align frags. This is
@@ -310,6 +312,7 @@ struct i386_tc_frag_data
(FRAGP)->tc_frag_data.isa = cpu_arch_isa; \
(FRAGP)->tc_frag_data.isa_flags = cpu_arch_isa_flags; \
(FRAGP)->tc_frag_data.tune = cpu_arch_tune; \
+ (FRAGP)->tc_frag_data.cpunop = cpu_arch_flags.bitfield.cpunop; \
(FRAGP)->tc_frag_data.code = i386_flag_code; \
(FRAGP)->tc_frag_data.max_bytes = (MAX_BYTES); \
(FRAGP)->tc_frag_data.length = 0; \
diff --git a/gas/testsuite/gas/i386/x86-64-nops-1a-core2.d b/gas/testsuite/gas/i386/x86-64-nops-1a-core2.d
new file mode 100644
index 0000000..82b32df
--- /dev/null
+++ b/gas/testsuite/gas/i386/x86-64-nops-1a-core2.d
@@ -0,0 +1,5 @@
+#as: -march=core2+nonop
+#source: nops-1.s
+#objdump: -drw
+#name: x86-64 -march=core2+nonop nops 1
+#dump: x86-64-nops-1-pentium.d
diff --git a/gas/testsuite/gas/i386/x86-64-nops-1a-g64.d b/gas/testsuite/gas/i386/x86-64-nops-1a-g64.d
new file mode 100644
index 0000000..cbbe770
--- /dev/null
+++ b/gas/testsuite/gas/i386/x86-64-nops-1a-g64.d
@@ -0,0 +1,5 @@
+#as: -march=generic64+nonop
+#source: nops-1.s
+#objdump: -drw
+#name: x86-64 -march=generic64+nonop nops 1
+#dump: x86-64-nops-1-pentium.d
diff --git a/gas/testsuite/gas/i386/x86-64.exp b/gas/testsuite/gas/i386/x86-64.exp
index 3d521f6..29909a8 100644
--- a/gas/testsuite/gas/i386/x86-64.exp
+++ b/gas/testsuite/gas/i386/x86-64.exp
@@ -109,6 +109,8 @@ run_dump_test "x86-64-nops-1-g64"
run_dump_test "x86-64-nops-1-k8"
run_dump_test "x86-64-nops-1-core2"
run_dump_test "x86-64-nops-1-pentium"
+run_dump_test "x86-64-nops-1a-g64"
+run_dump_test "x86-64-nops-1a-core2"
run_dump_test "x86-64-nops-2"
run_dump_test "x86-64-nops-3"
run_dump_test "x86-64-nops-4"