diff --git a/llvm/include/llvm/ProfileData/ProfileCommon.h b/llvm/include/llvm/ProfileData/ProfileCommon.h
--- a/llvm/include/llvm/ProfileData/ProfileCommon.h
+++ b/llvm/include/llvm/ProfileData/ProfileCommon.h
@@ -33,8 +33,8 @@
 
 } // 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
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -473,12 +473,12 @@
   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
--- a/llvm/lib/CodeGen/MachineFunctionSplitter.cpp
+++ b/llvm/lib/CodeGen/MachineFunctionSplitter.cpp
@@ -107,8 +107,8 @@
   // 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
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -621,7 +621,7 @@
   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 @@
       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 @@
   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
--- a/llvm/test/CodeGen/X86/machine-function-splitter.ll
+++ b/llvm/test/CodeGen/X86/machine-function-splitter.ll
@@ -207,8 +207,8 @@
 !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
--- a/llvm/test/CodeGen/X86/mingw-comdats.ll
+++ b/llvm/test/CodeGen/X86/mingw-comdats.ll
@@ -74,14 +74,26 @@
 ; 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
--- /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
--- a/llvm/test/Transforms/CodeGenPrepare/X86/section-samplepgo.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/section-samplepgo.ll
@@ -34,8 +34,8 @@
   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
--- a/llvm/test/Transforms/CodeGenPrepare/X86/section.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/section.ll
@@ -66,8 +66,8 @@
   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
--- a/llvm/test/Transforms/HotColdSplit/coldentrycount.ll
+++ b/llvm/test/Transforms/HotColdSplit/coldentrycount.ll
@@ -27,9 +27,9 @@
 ; 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 @@
 !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
--- a/llvm/test/Transforms/SampleProfile/section-accurate-samplepgo.ll
+++ b/llvm/test/Transforms/SampleProfile/section-accurate-samplepgo.ll
@@ -36,11 +36,11 @@
 
 ; 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}