On 26/1/24 12:24, Paolo Bonzini wrote:
On Fri, Jan 26, 2024 at 11:38 AM Philippe Mathieu-Daudé
<phi...@linaro.org> wrote:
On 25/1/24 17:56, Philippe Mathieu-Daudé wrote:
Add a Coccinelle script to convert the following slow path
(due to the QOM cast macro):
&ARCH_CPU(..)->env
to the following fast path:
cpu_env(..)
Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>
---
MAINTAINERS | 1 +
scripts/coccinelle/cpu_env.cocci_template | 60 +++++++++++++++++++++++
2 files changed, 61 insertions(+)
create mode 100644 scripts/coccinelle/cpu_env.cocci_template
diff --git a/scripts/coccinelle/cpu_env.cocci_template
b/scripts/coccinelle/cpu_env.cocci_template
new file mode 100644
index 0000000000..53aa3a1fea
--- /dev/null
+++ b/scripts/coccinelle/cpu_env.cocci_template
@@ -0,0 +1,60 @@
+/*
+
+ Convert &ARCH_CPU(..)->env to use cpu_env(..).
+
+ Rationale: ARCH_CPU() might be slow, being a QOM cast macro.
+ cpu_env() is its fast equivalent.
+
+ SPDX-License-Identifier: GPL-2.0-or-later
+ SPDX-FileCopyrightText: Linaro Ltd 2024
+ SPDX-FileContributor: Philippe Mathieu-Daudé
+
+ Usage as of v8.2.0:
+
+ $ for targetdir in target/*; do test -d $targetdir || continue; \
+ export target=${targetdir:7}; \
+ sed \
+ -e "s/__CPUArchState__/$( \
+ git grep -h --no-line-number '@env: #CPU.*State' \
+ target/$target/cpu.h \
+ | sed -n -e 's/.*\(CPU.*State\).\?/\1/p')/g" \
+ -e "s/__ARCHCPU__/$( \
+ git grep -h --no-line-number OBJECT_DECLARE_CPU_TYPE.*CPU \
+ target/$target/cpu-qom.h \
+ | sed -n -e 's/.*(\(.*\), .*, .*)/\1/p')/g" \
+ -e "s/__ARCH_CPU__/$( \
+ git grep -h --no-line-number OBJECT_DECLARE_CPU_TYPE.*CPU \
+ target/$target/cpu-qom.h \
+ | sed -n -e 's/.*(.*, .*, \(.*\))/\1/p')/g" \
+ < scripts/coccinelle/cpu_env.cocci_template \
+ > $TMPDIR/cpu_env_$target.cocci; \
+ for dir in hw target/$target; do \
+ spatch --macro-file scripts/cocci-macro-file.h \
+ --sp-file $TMPDIR/cpu_env_$target.cocci \
+ --keep-comments \
+ --dir $dir \
+ --in-place; \
+ done; \
+ done
+
+*/
+
+@ CPUState_arg_used @
+CPUState *cs;
+identifier cpu;
+identifier env;
+@@
+- __ARCHCPU__ *cpu = __ARCH_CPU__(cs);
Here we remove ARCH_CPU(), ...
+- __CPUArchState__ *env = &cpu->env;
++ __CPUArchState__ *env = cpu_env(cs);
+ ... when != cpu
+
+@ depends on never CPUState_arg_used @
+identifier obj;
+identifier cpu;
+identifier env;
+@@
+- __ARCHCPU__ *cpu = __ARCH_CPU__(obj);
+- __CPUArchState__ *env = &cpu->env;
++ __CPUArchState__ *env = cpu_env(CPU(obj));
... but here we just change it by a CPU() QOM call.
So this 2nd change is just style cleanup.
Can you also add a hunk that is
CPUState *cs;
@@
- CPU(cs)
+ cs
to clean up on the second? cpu_env(CPU(current_cpu)) is suboptimal
and also a bit ugly.
These case should be cleaned because this is already a CPUState*:
+ CPUX86State *env = cpu_env(CPU(current_cpu));
+ CPUPPCState *env = cpu_env(CPU(first_cpu));
But these (instance_init and QOM visitors) can't, the argument
isn't a CPUState*:
static void ev4_cpu_initfn(Object *obj)
{
- AlphaCPU *cpu = ALPHA_CPU(obj);
- CPUAlphaState *env = &cpu->env;
+ CPUAlphaState *env = cpu_env(CPU(obj));
@@ -5186,8 +5179,7 @@ static char *x86_cpuid_get_vendor(Object *obj,
Error **errp)
static void x86_cpuid_set_vendor(Object *obj, const char *value,
Error **errp)
{
- X86CPU *cpu = X86_CPU(obj);
- CPUX86State *env = &cpu->env;
+ CPUX86State *env = cpu_env(CPU(obj));
That said, these visitors take a Object* param because they implement
the generic QOM visitor API, but we know the visitor are registered
on classes/objects implementing CPUState, so QOM cast macro is
redundant.