[PATCH] D46874: [MC] - Add .stack_size sections into groups and link them with .text

[George Rimar via Phabricator via llvm-commits]

grimar updated this revision to Diff 148182.
grimar added a comment.

- Do not do unification when no -ffunction-section is specified.


https://reviews.llvm.org/D46874

Files:
  include/llvm/MC/MCObjectFileInfo.h
  lib/CodeGen/AsmPrinter/AsmPrinter.cpp
  lib/MC/MCObjectFileInfo.cpp
  test/CodeGen/X86/stack-size-section2.ll


Index: test/CodeGen/X86/stack-size-section2.ll
===================================================================
--- test/CodeGen/X86/stack-size-section2.ll
+++ test/CodeGen/X86/stack-size-section2.ll
@@ -0,0 +1,29 @@
+; RUN: llc < %s -mtriple=x86_64-linux -stack-size-section -function-sections | FileCheck %s
+
+; Check we add SHF_LINK_ORDER for .stack_sizes and link it with the corresponding .text sections.
+
+; CHECK: .section        .text._Z3barv,"ax", at progbits
+; CHECK: .section        .stack_sizes,"o", at progbits,.text._Z3barv,unique,0
+
+; CHECK: .section        .text._Z3foov,"ax", at progbits
+; CHECK: .section        .stack_sizes,"o", at progbits,.text._Z3foov,unique,1
+
+; Check we add .stack_size section to COMDAT with the corresponding .text section if such COMDAT exists. 
+
+; CHECK: .section        .text._Z4fooTIiET_v,"axG", at progbits,_Z4fooTIiET_v,comdat
+; CHECK: .section        .stack_sizes,"Go", at progbits,_Z4fooTIiET_v,comdat,.text._Z4fooTIiET_v,unique,2
+
+$_Z4fooTIiET_v = comdat any
+
+define dso_local i32 @_Z3barv() {
+  ret i32 0
+}
+
+define dso_local i32 @_Z3foov() {
+  %1 = call i32 @_Z4fooTIiET_v()
+  ret i32 %1
+}
+
+define linkonce_odr dso_local i32 @_Z4fooTIiET_v() comdat {
+  ret i32 0
+}
Index: lib/MC/MCObjectFileInfo.cpp
===================================================================
--- lib/MC/MCObjectFileInfo.cpp
+++ lib/MC/MCObjectFileInfo.cpp
@@ -948,3 +948,22 @@
   return Ctx->getELFSection(".debug_types", ELF::SHT_PROGBITS, ELF::SHF_GROUP,
                             0, utostr(Hash));
 }
+
+MCSection *MCObjectFileInfo::getStackSizesSection(const MCSection &TextSec,
+                                                  unsigned ID) const {
+  if (Env != IsELF)
+    return StackSizesSection;
+
+  unsigned Flags = ELF::SHF_LINK_ORDER;
+
+  StringRef GroupName;
+  const MCSectionELF &ElfSec = static_cast<const MCSectionELF &>(TextSec);
+  if (const MCSymbol *Group = ElfSec.getGroup()) {
+    GroupName = Group->getName();
+    Flags |= ELF::SHF_GROUP;
+  }
+
+  const MCSymbolELF *Link = cast<MCSymbolELF>(TextSec.getBeginSymbol());
+  return Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, Flags, 0,
+                            GroupName, ID, Link);
+}
Index: lib/CodeGen/AsmPrinter/AsmPrinter.cpp
===================================================================
--- lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -989,7 +989,13 @@
   if (!MF.getTarget().Options.EmitStackSizeSection)
     return;
 
-  MCSection *StackSizeSection = getObjFileLowering().getStackSizesSection();
+  // If -ffunction-section is specified, we want to emit .stack_sizes section
+  // for each .text.X section. Here we select the unique ID based on a unique
+  // function number.
+  unsigned UniqueID =
+      MF.getTarget().Options.FunctionSections ? MF.getFunctionNumber() : ~0;
+  MCSection *StackSizeSection =
+      getObjFileLowering().getStackSizesSection(*getCurrentSection(), UniqueID);
   if (!StackSizeSection)
     return;
 
Index: include/llvm/MC/MCObjectFileInfo.h
===================================================================
--- include/llvm/MC/MCObjectFileInfo.h
+++ include/llvm/MC/MCObjectFileInfo.h
@@ -299,7 +299,7 @@
   MCSection *getStackMapSection() const { return StackMapSection; }
   MCSection *getFaultMapSection() const { return FaultMapSection; }
 
-  MCSection *getStackSizesSection() const { return StackSizesSection; }
+  MCSection *getStackSizesSection(const MCSection &TextSec, unsigned ID) const;
 
   // ELF specific sections.
   MCSection *getDataRelROSection() const { return DataRelROSection; }


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