3733463dbb
Clang FE currently has hot/cold function attribute. But we only have
cold function attribute in LLVM IR.
This patch adds support of hot function attribute to LLVM IR. This
attribute will be used in setting function section prefix/suffix.
Currently .hot and .unlikely suffix only are added in PGO (Sample PGO)
compilation (through isFunctionHotInCallGraph and
isFunctionColdInCallGraph).
This patch changes the behavior. The new behavior is:
(1) If the user annotates a function as hot or isFunctionHotInCallGraph
is true, this function will be marked as hot. Otherwise,
(2) If the user annotates a function as cold or
isFunctionColdInCallGraph is true, this function will be marked as
cold.
The changes are:
(1) user annotated function attribute will used in setting function
section prefix/suffix.
(2) hot attribute overwrites profile count based hotness.
(3) profile count based hotness overwrite user annotated cold attribute.
The intention for these changes is to provide the user a way to mark
certain function as hot in cases where training input is hard to cover
all the hot functions.
Differential Revision: https://reviews.llvm.org/D92493
130 lines
4.0 KiB
C
130 lines
4.0 KiB
C
// RUN: %clang_cc1 -emit-llvm -fcf-protection=branch -triple i386-linux-gnu -o %t %s
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// RUN: FileCheck --input-file=%t %s
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// CHECK: @t5 = weak global i32 2
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int t5 __attribute__((weak)) = 2;
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// CHECK: @t13 = global %struct.s0 zeroinitializer, section "SECT"
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struct s0 { int x; };
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struct s0 t13 __attribute__((section("SECT"))) = { 0 };
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// CHECK: @t14.x = internal global i32 0, section "SECT"
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void t14(void) {
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static int x __attribute__((section("SECT"))) = 0;
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}
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// CHECK: @t18 = global i32 1, align 4
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extern int t18 __attribute__((weak_import));
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int t18 = 1;
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// CHECK: @t16 = extern_weak global i32
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extern int t16 __attribute__((weak_import));
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// CHECK: @t6 = protected global i32 0
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int t6 __attribute__((visibility("protected")));
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// CHECK: @t12 = global i32 0, section "SECT"
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int t12 __attribute__((section("SECT")));
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// CHECK: @t9 = weak alias void (...), bitcast (void ()* @__t8 to void (...)*)
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void __t8() {}
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void t9() __attribute__((weak, alias("__t8")));
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// CHECK: declare extern_weak i32 @t15()
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int __attribute__((weak_import)) t15(void);
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int t17() {
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return t15() + t16;
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}
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// CHECK: define void @t1() [[NR:#[0-9]+]] {
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void t1() __attribute__((noreturn));
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void t1() { while (1) {} }
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// CHECK: define void @t2() [[NUW:#[0-9]+]] {
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void t2() __attribute__((nothrow));
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void t2() {}
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// CHECK: define weak void @t3() [[NUW]] {
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void t3() __attribute__((weak));
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void t3() {}
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// CHECK: define hidden void @t4() [[NUW]] {
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void t4() __attribute__((visibility("hidden")));
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void t4() {}
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// CHECK: define void @t7() [[NR]] {
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void t7() __attribute__((noreturn, nothrow));
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void t7() { while (1) {} }
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// CHECK: define void @t72() [[COLDDEF:#[0-9]+]] {
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void t71(void) __attribute__((cold));
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void t72() __attribute__((cold));
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void t72() { t71(); }
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// CHECK: call void @t71() [[COLDSITE:#[0-9]+]]
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// CHECK: declare void @t71() [[COLDDECL:#[0-9]+]]
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// CHECK: define void @t82() [[HOTDEF:#[0-9]+]] {
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void t81(void) __attribute__((hot));
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void t82() __attribute__((hot));
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void t82() { t81(); }
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// CHECK: call void @t81() [[HOTSITE:#[0-9]+]]
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// CHECK: declare void @t81() [[HOTDECL:#[0-9]+]]
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// CHECK: define void @t10() [[NUW]] section "xSECT" {
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void t10(void) __attribute__((section("xSECT")));
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void t10(void) {}
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// CHECK: define void @t11() [[NUW]] section "xSECT" {
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void __attribute__((section("xSECT"))) t11(void) {}
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// CHECK: define i32 @t19() [[NUW]] {
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extern int t19(void) __attribute__((weak_import));
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int t19(void) {
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// RUN: %clang_cc1 -emit-llvm -fcf-protection=branch -triple i386-linux-gnu -o %t %s
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// RUN: %clang_cc1 -emit-llvm -fcf-protection=branch -triple i386-linux-gnu -o %t %s
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// RUN: %clang_cc1 -emit-llvm -fcf-protection=branch -triple i386-linux-gnu -o %t %s
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return 10;
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}
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// CHECK:define void @t20() [[NUW]] {
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// CHECK: call void @abort()
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// CHECK-NEXT: unreachable
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void t20(void) {
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__builtin_abort();
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}
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void (__attribute__((fastcall)) *fptr)(int);
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void t21(void) {
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fptr(10);
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}
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// CHECK: [[FPTRVAR:%[a-z0-9]+]] = load void (i32)*, void (i32)** @fptr
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// CHECK-NEXT: call x86_fastcallcc void [[FPTRVAR]](i32 inreg 10)
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// PR9356: We might want to err on this, but for now at least make sure we
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// use the section in the definition.
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void __attribute__((section(".foo"))) t22(void);
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void __attribute__((section(".bar"))) t22(void) {}
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// CHECK: define void @t22() [[NUW]] section ".bar"
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// CHECK: define void @t23() [[NOCF_CHECK_FUNC:#[0-9]+]]
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void __attribute__((nocf_check)) t23(void) {}
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// CHECK: call void %{{[a-z0-9]+}}() [[NOCF_CHECK_CALL:#[0-9]+]]
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typedef void (*f_t)(void);
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void t24(f_t f1) {
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__attribute__((nocf_check)) f_t p = f1;
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(*p)();
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}
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// CHECK: attributes [[NUW]] = { noinline nounwind{{.*}} }
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// CHECK: attributes [[NR]] = { noinline noreturn nounwind{{.*}} }
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// CHECK: attributes [[COLDDEF]] = { cold {{.*}}}
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// CHECK: attributes [[COLDDECL]] = { cold {{.*}}}
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// CHECK: attributes [[HOTDEF]] = { hot {{.*}}}
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// CHECK: attributes [[HOTDECL]] = { hot {{.*}}}
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// CHECK: attributes [[NOCF_CHECK_FUNC]] = { nocf_check {{.*}}}
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// CHECK: attributes [[COLDSITE]] = { cold {{.*}}}
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// CHECK: attributes [[HOTSITE]] = { hot {{.*}}}
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// CHECK: attributes [[NOCF_CHECK_CALL]] = { nocf_check }
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