[CodeGen] Add text section prefix for COFF object file

Text section prefix is created in CodeGenPrepare, it's file format independent implementation,  text section name is written into object file in TargetLoweringObjectFile, it's file format dependent implementation, port code of adding text section prefix to text section name from ELF to COFF.
Different with ELF that use '.' as concatenation character, COFF use '$' as concatenation character. That is, concatenation character is variable, so split concatenation character from text section prefix.
Text section prefix is existing feature of ELF, it can help to reduce icache and itlb misses, it's also make possible aggregate other compilers e.g. v8 created same prefix sections. Furthermore, the recent feature Machine Function Splitter (basic block level text prefix section) is based on text section prefix.

Reviewed By: pengfei, rnk

Differential Revision: https://reviews.llvm.org/D92073

diff --git a/llvm/include/llvm/ProfileData/ProfileCommon.h b/llvm/include/llvm/ProfileData/ProfileCommon.h
index 14c305b..6bb5825 100644 (file)
--- a/llvm/include/llvm/ProfileData/ProfileCommon.h
+++ b/llvm/include/llvm/ProfileData/ProfileCommon.h
@@ -33,8 +33,8 @@ class FunctionSamples;
 
 } // end namespace sampleprof
 
-inline const char *getHotSectionPrefix() { return ".hot"; }
-inline const char *getUnlikelySectionPrefix() { return ".unlikely"; }
+inline const char *getHotSectionPrefix() { return "hot"; }
+inline const char *getUnlikelySectionPrefix() { return "unlikely"; }
 
 class ProfileSummaryBuilder {
 private:

diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 40e92b9..9b44b30 100644 (file)
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -473,12 +473,12 @@ bool CodeGenPrepare::runOnFunction(Function &F) {
   OptSize = F.hasOptSize();
   if (ProfileGuidedSectionPrefix) {
     if (PSI->isFunctionHotInCallGraph(&F, *BFI))
-      F.setSectionPrefix(".hot");
+      F.setSectionPrefix("hot");
     else if (PSI->isFunctionColdInCallGraph(&F, *BFI))
-      F.setSectionPrefix(".unlikely");
+      F.setSectionPrefix("unlikely");
     else if (ProfileUnknownInSpecialSection && PSI->hasPartialSampleProfile() &&
              PSI->isFunctionHotnessUnknown(F))
-      F.setSectionPrefix(".unknown");
+      F.setSectionPrefix("unknown");
   }
 
   /// This optimization identifies DIV instructions that can be

diff --git a/llvm/lib/CodeGen/MachineFunctionSplitter.cpp b/llvm/lib/CodeGen/MachineFunctionSplitter.cpp
index b2f474a..483809a 100644 (file)
--- a/llvm/lib/CodeGen/MachineFunctionSplitter.cpp
+++ b/llvm/lib/CodeGen/MachineFunctionSplitter.cpp
@@ -107,8 +107,8 @@ bool MachineFunctionSplitter::runOnMachineFunction(MachineFunction &MF) {
   // or functions of unknown hotness. Lukewarm functions have no prefix.
   Optional<StringRef> SectionPrefix = MF.getFunction().getSectionPrefix();
   if (SectionPrefix.hasValue() &&
-      (SectionPrefix.getValue().equals(".unlikely") ||
-       SectionPrefix.getValue().equals(".unknown"))) {
+      (SectionPrefix.getValue().equals("unlikely") ||
+       SectionPrefix.getValue().equals("unknown"))) {
     return false;
   }
 

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 4c8caa0..2e32eab 100644 (file)
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -621,7 +621,7 @@ getELFSectionNameForGlobal(const GlobalObject *GO, SectionKind Kind,
   bool HasPrefix = false;
   if (const auto *F = dyn_cast<Function>(GO)) {
     if (Optional<StringRef> Prefix = F->getSectionPrefix()) {
-      Name += *Prefix;
+      raw_svector_ostream(Name) << '.' << *Prefix;
       HasPrefix = true;
     }
   }
@@ -1573,6 +1573,10 @@ MCSection *TargetLoweringObjectFileCOFF::SelectSectionForGlobal(
       MCSymbol *Sym = TM.getSymbol(ComdatGV);
       StringRef COMDATSymName = Sym->getName();
 
+      if (const auto *F = dyn_cast<Function>(GO))
+        if (Optional<StringRef> Prefix = F->getSectionPrefix())
+          raw_svector_ostream(Name) << '$' << *Prefix;
+
       // Append "$symbol" to the section name *before* IR-level mangling is
       // applied when targetting mingw. This is what GCC does, and the ld.bfd
       // COFF linker will not properly handle comdats otherwise.
@@ -2020,7 +2024,7 @@ static MCSectionWasm *selectWasmSectionForGlobal(
   if (const auto *F = dyn_cast<Function>(GO)) {
     const auto &OptionalPrefix = F->getSectionPrefix();
     if (OptionalPrefix)
-      Name += *OptionalPrefix;
+      raw_svector_ostream(Name) << '.' << *OptionalPrefix;
   }
 
   if (EmitUniqueSection && UniqueSectionNames) {

diff --git a/llvm/test/CodeGen/X86/machine-function-splitter.ll b/llvm/test/CodeGen/X86/machine-function-splitter.ll
index 5222b4d..67edd7e 100644 (file)
--- a/llvm/test/CodeGen/X86/machine-function-splitter.ll
+++ b/llvm/test/CodeGen/X86/machine-function-splitter.ll
@@ -207,8 +207,8 @@ declare i32 @__gxx_personality_v0(...)
 !12 = !{i32 999900, i64 100, i32 1}
 !13 = !{i32 999999, i64 1, i32 2}
 !14 = !{!"function_entry_count", i64 7000}
-!15 = !{!"function_section_prefix", !".hot"}
-!16 = !{!"function_section_prefix", !".unlikely"}
+!15 = !{!"function_section_prefix", !"hot"}
+!16 = !{!"function_section_prefix", !"unlikely"}
 !17 = !{!"branch_weights", i32 7000, i32 0}
 !18 = !{!"branch_weights", i32 3000, i32 4000}
 !19 = !{!"branch_weights", i32 1000, i32 6000}

diff --git a/llvm/test/CodeGen/X86/mingw-comdats.ll b/llvm/test/CodeGen/X86/mingw-comdats.ll
index c7caf92..1cb1f80 100644 (file)
--- a/llvm/test/CodeGen/X86/mingw-comdats.ll
+++ b/llvm/test/CodeGen/X86/mingw-comdats.ll
@@ -74,14 +74,26 @@ entry:
 ; GNU32: .long 42
 
 
+define linkonce_odr dso_local i32 @_Z3fooj(i32 %x) !section_prefix !0 {
+entry:
+  %call = tail call i32 @_Z3bari(i32 %x)
+  %0 = load i32, i32* @gv, align 4
+  %add = add nsw i32 %0, %call
+  ret i32 %add
+}
+
 ; Make sure the assembler puts the .xdata and .pdata in sections with the right
 ; names.
 ; GNUOBJ: .text$_Z3fooi
 ; GNUOBJ: .xdata$_Z3fooi
+; GNUOBJ: .text$unlikely$_Z3fooj
+; GNUOBJ: .xdata$unlikely$_Z3fooj
 ; GNUOBJ: .data$gv
 ; GNUOBJ: .pdata$_Z3fooi
+; GNUOBJ: .pdata$unlikely$_Z3fooj
 
 declare dso_local i32 @_Z3bari(i32)
 
 attributes #0 = { norecurse uwtable }
 attributes #1 = { inlinehint uwtable }
+!0 = !{!"function_section_prefix", !"unlikely"}

diff --git a/llvm/test/CodeGen/X86/text-section-prefix.ll b/llvm/test/CodeGen/X86/text-section-prefix.ll
new file mode 100644 (file)
index 0000000..99e1436
--- /dev/null
+++ b/llvm/test/CodeGen/X86/text-section-prefix.ll
@@ -0,0 +1,26 @@
+; RUN: llc -mtriple x86_64-linux-gnu -function-sections %s -o - | FileCheck %s --check-prefix=ELF
+; RUN: llc -mtriple x86_64-linux-gnu -unique-section-names=0 -function-sections %s -o - | FileCheck %s --check-prefix=ELF-NOUNIQ
+; RUN: llc -mtriple x86_64-windows-msvc -function-sections %s -o - | FileCheck %s --check-prefix=COFF-MSVC
+; RUN: llc -mtriple x86_64-windows-gnu -function-sections %s -o - | FileCheck %s --check-prefix=COFF-GNU
+
+define void @foo1(i1 zeroext %0) nounwind !section_prefix !0 {
+;; CHECK hot section name
+; ELF:        .section  .text.hot.foo1,"ax",@progbits
+; ELF-NOUNIQ: .section  .text.hot.,"ax",@progbits,unique,1
+; COFF-MSVC:  .section  .text$hot,"xr",one_only,foo1
+; COFF-GNU:   .section  .text$hot$foo1,"xr",one_only,foo1
+  ret void
+}
+
+define void @foo2(i1 zeroext %0) nounwind !section_prefix !1 {
+;; CHECK unlikely section name
+; ELF:        .section  .text.unlikely.foo2,"ax",@progbits
+; ELF-NOUNIQ: .section  .text.unlikely.,"ax",@progbits,unique,2
+; COFF-MSVC:  .section  .text$unlikely,"xr",one_only,foo2
+; COFF-GNU:   .section  .text$unlikely$foo2,"xr",one_only,foo2
+  ret void
+}
+
+!0 = !{!"function_section_prefix", !"hot"}
+!1 = !{!"function_section_prefix", !"unlikely"}
+

diff --git a/llvm/test/Transforms/CodeGenPrepare/X86/section-samplepgo.ll b/llvm/test/Transforms/CodeGenPrepare/X86/section-samplepgo.ll
index 93d2a5f..58af88d 100644 (file)
--- a/llvm/test/Transforms/CodeGenPrepare/X86/section-samplepgo.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/section-samplepgo.ll
@@ -34,8 +34,8 @@ define void @cold_func() !prof !16 {
   ret void
 }
 
-; CHECK: ![[HOT_ID]] = !{!"function_section_prefix", !".hot"}
-; CHECK: ![[COLD_ID]] = !{!"function_section_prefix", !".unlikely"}
+; CHECK: ![[HOT_ID]] = !{!"function_section_prefix", !"hot"}
+; CHECK: ![[COLD_ID]] = !{!"function_section_prefix", !"unlikely"}
 !llvm.module.flags = !{!1}
 !1 = !{i32 1, !"ProfileSummary", !2}
 !2 = !{!3, !4, !5, !6, !7, !8, !9, !10}

diff --git a/llvm/test/Transforms/CodeGenPrepare/X86/section.ll b/llvm/test/Transforms/CodeGenPrepare/X86/section.ll
index 4347f57..7b91a95 100644 (file)
--- a/llvm/test/Transforms/CodeGenPrepare/X86/section.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/section.ll
@@ -66,8 +66,8 @@ define void @cold_func3() !prof !16 {
   ret void
 }
 
-; CHECK: ![[HOT_ID]] = !{!"function_section_prefix", !".hot"}
-; CHECK: ![[COLD_ID]] = !{!"function_section_prefix", !".unlikely"}
+; CHECK: ![[HOT_ID]] = !{!"function_section_prefix", !"hot"}
+; CHECK: ![[COLD_ID]] = !{!"function_section_prefix", !"unlikely"}
 !llvm.module.flags = !{!1}
 !1 = !{i32 1, !"ProfileSummary", !2}
 !2 = !{!3, !4, !5, !6, !7, !8, !9, !10}

diff --git a/llvm/test/Transforms/HotColdSplit/coldentrycount.ll b/llvm/test/Transforms/HotColdSplit/coldentrycount.ll
index 8964276..1b39a75 100644 (file)
--- a/llvm/test/Transforms/HotColdSplit/coldentrycount.ll
+++ b/llvm/test/Transforms/HotColdSplit/coldentrycount.ll
@@ -27,9 +27,9 @@ declare void @sink() cold
 ; CHECK: define {{.*}} @fun.cold.1{{.*}} ![[PROF:[0-9]+]] {{.*}}section_prefix ![[UNLIKELY:[0-9]+]]
 
 ; CHECK: ![[HOTPROF]] = !{!"function_entry_count", i64 100}
-; CHECK: ![[LIKELY]] = !{!"function_section_prefix", !".hot"}
+; CHECK: ![[LIKELY]] = !{!"function_section_prefix", !"hot"}
 ; CHECK: ![[PROF]] = !{!"function_entry_count", i64 0}
-; CHECK: ![[UNLIKELY]] = !{!"function_section_prefix", !".unlikely"}
+; CHECK: ![[UNLIKELY]] = !{!"function_section_prefix", !"unlikely"}
 
 !llvm.module.flags = !{!0}
 !0 = !{i32 1, !"ProfileSummary", !1}
@@ -47,6 +47,6 @@ declare void @sink() cold
 !12 = !{i32 999000, i64 100, i32 1}
 !13 = !{i32 999999, i64 1, i32 2}
 !14 = !{!"function_entry_count", i64 100}
-!15 = !{!"function_section_prefix", !".hot"}
+!15 = !{!"function_section_prefix", !"hot"}
 !16 = !{!"function_entry_count", i64 0}
-!17 = !{!"function_section_prefix", !".unlikely"}
+!17 = !{!"function_section_prefix", !"unlikely"}

diff --git a/llvm/test/Transforms/SampleProfile/section-accurate-samplepgo.ll b/llvm/test/Transforms/SampleProfile/section-accurate-samplepgo.ll
index 9fc3402..b6c48d8 100644 (file)
--- a/llvm/test/Transforms/SampleProfile/section-accurate-samplepgo.ll
+++ b/llvm/test/Transforms/SampleProfile/section-accurate-samplepgo.ll
@@ -36,11 +36,11 @@ attributes #1 = { "use-sample-profile" }
 
 ; CHECK: ![[NOPROFILE_ID]] = !{!"function_entry_count", i64 -1}
 ; CHECK: ![[ZERO_ID]] = !{!"function_entry_count", i64 0}
-; CHECK: ![[COLD_ID]] = !{!"function_section_prefix", !".unlikely"}
+; CHECK: ![[COLD_ID]] = !{!"function_section_prefix", !"unlikely"}
 ; UNKNOWN: ![[NOPROFILE_ID]] = !{!"function_entry_count", i64 -1}
-; UNKNOWN: ![[UNKNOWN_ID]] = !{!"function_section_prefix", !".unknown"}
+; UNKNOWN: ![[UNKNOWN_ID]] = !{!"function_section_prefix", !"unknown"}
 ; ACCURATE: ![[ZERO_ID]] = !{!"function_entry_count", i64 0}
-; ACCURATE: ![[COLD_ID]] = !{!"function_section_prefix", !".unlikely"}
+; ACCURATE: ![[COLD_ID]] = !{!"function_section_prefix", !"unlikely"}
 !llvm.module.flags = !{!1}
 !1 = !{i32 1, !"ProfileSummary", !2}
 !2 = !{!3, !4, !5, !6, !7, !8, !9, !10}