Add hook in MCSection to decide when to use "optimized nops", for each

section kind. Previously, optimized nops were only used for MachO.
Also added tests for ELF and COFF.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115523 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/MC/MCSection.h b/include/llvm/MC/MCSection.h
index 5c997357c9d3818db320a29d5940760009a33b57..3e5b5f13f324433e1a506ecc803fcde94557c19a 100644 (file)
--- a/include/llvm/MC/MCSection.h
+++ b/include/llvm/MC/MCSection.h
@@ -61,6 +61,10 @@ namespace llvm {
       return false;
     }
 
+    // UseCodeAlign - Return true if a .align directive should use
+    // "optimized nops" to fill instead of 0s.
+    virtual bool UseCodeAlign() const = 0;
+
     static bool classof(const MCSection *) { return true; }
   };
 

diff --git a/include/llvm/MC/MCSectionCOFF.h b/include/llvm/MC/MCSectionCOFF.h
index f828e1060fe62a9c7d59eec74a12fde9eb1737cc..62d07cf4368c99865917a518ebdbbb0fcb561494 100644 (file)
--- a/include/llvm/MC/MCSectionCOFF.h
+++ b/include/llvm/MC/MCSectionCOFF.h
@@ -55,6 +55,7 @@ namespace llvm {
     
     virtual void PrintSwitchToSection(const MCAsmInfo &MAI,
                                       raw_ostream &OS) const;
+    virtual bool UseCodeAlign() const;
 
     static bool classof(const MCSection *S) {
       return S->getVariant() == SV_COFF;

diff --git a/include/llvm/MC/MCSectionELF.h b/include/llvm/MC/MCSectionELF.h
index f97ab1671180e14b7a0fcb0a74ed2190f31394b5..a92d0f2c9507ea5a2c3efb62a51b79383f115c65 100644 (file)
--- a/include/llvm/MC/MCSectionELF.h
+++ b/include/llvm/MC/MCSectionELF.h
@@ -178,7 +178,8 @@ public:
   
   void PrintSwitchToSection(const MCAsmInfo &MAI,
                             raw_ostream &OS) const;
-  
+  virtual bool UseCodeAlign() const;
+
   /// isBaseAddressKnownZero - We know that non-allocatable sections (like
   /// debug info) have a base of zero.
   virtual bool isBaseAddressKnownZero() const {

diff --git a/include/llvm/MC/MCSectionMachO.h b/include/llvm/MC/MCSectionMachO.h
index 2d9d1333dbe23a9d917447a397902ac781501780..19d003a3b5a4bd5b77f787c00864ed537708f22d 100644 (file)
--- a/include/llvm/MC/MCSectionMachO.h
+++ b/include/llvm/MC/MCSectionMachO.h
@@ -165,6 +165,7 @@ public:
 
   virtual void PrintSwitchToSection(const MCAsmInfo &MAI,
                                     raw_ostream &OS) const;
+  virtual bool UseCodeAlign() const;
 
   static bool classof(const MCSection *S) {
     return S->getVariant() == SV_MachO;

diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index fbac34a15ea4e5f4ee98eeb3402069d54f78961f..688827d2c76917c0f181e8757aca11e8940b69a7 100644 (file)
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -1654,12 +1654,7 @@ bool AsmParser::ParseDirectiveAlign(bool IsPow2, unsigned ValueSize) {
 
   // Check whether we should use optimal code alignment for this .align
   // directive.
-  //
-  // FIXME: This should be using a target hook.
-  bool UseCodeAlign = false;
-  if (const MCSectionMachO *S = dyn_cast<MCSectionMachO>(
-        getStreamer().getCurrentSection()))
-    UseCodeAlign = S->hasAttribute(MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS);
+  bool UseCodeAlign = getStreamer().getCurrentSection()->UseCodeAlign();
   if ((!HasFillExpr || Lexer.getMAI().getTextAlignFillValue() == FillExpr) &&
       ValueSize == 1 && UseCodeAlign) {
     getStreamer().EmitCodeAlignment(Alignment, MaxBytesToFill);

diff --git a/lib/MC/MCSectionCOFF.cpp b/lib/MC/MCSectionCOFF.cpp
index eb531600f72736e55259b11bbc3e243eb9fc29ab..0909df42227cf4c260d8081716df07fa06c416c2 100644 (file)
--- a/lib/MC/MCSectionCOFF.cpp
+++ b/lib/MC/MCSectionCOFF.cpp
@@ -74,3 +74,7 @@ void MCSectionCOFF::PrintSwitchToSection(const MCAsmInfo &MAI,
     }
   }
 }
+
+bool MCSectionCOFF::UseCodeAlign() const {
+  return getKind().isText();
+}

diff --git a/lib/MC/MCSectionELF.cpp b/lib/MC/MCSectionELF.cpp
index ef935d0c64bae09de11c862250e0931fdbfef598..133cad1b32cf4c3527611a6cd604f22f539df822 100644 (file)
--- a/lib/MC/MCSectionELF.cpp
+++ b/lib/MC/MCSectionELF.cpp
@@ -112,6 +112,10 @@ void MCSectionELF::PrintSwitchToSection(const MCAsmInfo &MAI,
   OS << '\n';
 }
 
+bool MCSectionELF::UseCodeAlign() const {
+  return getFlags() & MCSectionELF::SHF_EXECINSTR;
+}
+
 // HasCommonSymbols - True if this section holds common symbols, this is
 // indicated on the ELF object file by a symbol with SHN_COMMON section 
 // header index.

diff --git a/lib/MC/MCSectionMachO.cpp b/lib/MC/MCSectionMachO.cpp
index ded3b20eaf531973d81ad40ec3eac29d03d946c5..12b3efe663f42b92baf8bc92dad94b4d8719beaf 100644 (file)
--- a/lib/MC/MCSectionMachO.cpp
+++ b/lib/MC/MCSectionMachO.cpp
@@ -148,6 +148,10 @@ void MCSectionMachO::PrintSwitchToSection(const MCAsmInfo &MAI,
   OS << '\n';
 }
 
+bool MCSectionMachO::UseCodeAlign() const {
+  return hasAttribute(MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS);
+}
+
 /// StripSpaces - This removes leading and trailing spaces from the StringRef.
 static void StripSpaces(StringRef &Str) {
   while (!Str.empty() && isspace(Str[0]))
@@ -283,4 +287,3 @@ std::string MCSectionMachO::ParseSectionSpecifier(StringRef Spec,        // In.
   
   return "";
 }
-

diff --git a/lib/Target/PIC16/PIC16Section.cpp b/lib/Target/PIC16/PIC16Section.cpp
index 2505b111f1e80ac5f83058aaa1807f77f4d1c885..7664fbbb7d40672ce5496390b989759a976a5be7 100644 (file)
--- a/lib/Target/PIC16/PIC16Section.cpp
+++ b/lib/Target/PIC16/PIC16Section.cpp
@@ -102,3 +102,7 @@ void PIC16Section::PrintSwitchToSection(const MCAsmInfo &MAI,
 
   OS << '\n';
 }
+
+bool PIC16Section::UseCodeAlign() const {
+  return isCODE_Type();
+}

diff --git a/lib/Target/PIC16/PIC16Section.h b/lib/Target/PIC16/PIC16Section.h
index 5b33b51a386627a4ab27c7806a8d4ea82b19cd8d..98e590229bd6bd4f6999859eebed6d8bc89bf025 100644 (file)
--- a/lib/Target/PIC16/PIC16Section.h
+++ b/lib/Target/PIC16/PIC16Section.h
@@ -88,6 +88,8 @@ namespace llvm {
     virtual void PrintSwitchToSection(const MCAsmInfo &MAI,
                                       raw_ostream &OS) const;
 
+    virtual bool UseCodeAlign() const;
+
     static bool classof(const MCSection *S) {
       return S->getVariant() == SV_PIC16;
     }

diff --git a/test/MC/COFF/align-nops.s b/test/MC/COFF/align-nops.s
new file mode 100644 (file)
index 0000000..f190fdb
--- /dev/null
+++ b/test/MC/COFF/align-nops.s
@@ -0,0 +1,45 @@
+// RUN: llvm-mc -filetype=obj -triple i686-pc-win32 %s -o %t
+// RUN: coff-dump.py %abs_tmp | FileCheck %s
+        
+// Test that we get optimal nops in text
+    .text
+f0:
+    .long 0
+    .align  8, 0x90
+    .long 0
+    .align  8
+
+// But not in another section
+    .data
+    .long 0
+    .align  8, 0x90
+    .long 0
+    .align  8
+
+//CHECK:         Name                     = .text
+//CHECK-NEXT:    VirtualSize
+//CHECK-NEXT:    VirtualAddress
+//CHECK-NEXT:    SizeOfRawData            = 16
+//CHECK-NEXT:    PointerToRawData
+//CHECK-NEXT:    PointerToRelocations
+//CHECK-NEXT:    PointerToLineNumbers
+//CHECK-NEXT:    NumberOfRelocations
+//CHECK-NEXT:    NumberOfLineNumbers
+//CHECK-NEXT:    Charateristics           = 0x400001
+//CHECK-NEXT:        IMAGE_SCN_ALIGN_8BYTES
+//CHECK-NEXT:      SectionData              = 
+//CHECK-NEXT:        00 00 00 00 0F 1F 40 00 - 00 00 00 00 0F 1F 40 00
+
+//CHECK:         Name                     = .data
+//CHECK-NEXT:      VirtualSize
+//CHECK-NEXT:      VirtualAddress
+//CHECK-NEXT:      SizeOfRawData            = 16
+//CHECK-NEXT:      PointerToRawData
+//CHECK-NEXT:      PointerToRelocations
+//CHECK-NEXT:      PointerToLineNumbers
+//CHECK-NEXT:      NumberOfRelocations
+//CHECK-NEXT:      NumberOfLineNumbers
+//CHECK-NEXT:      Charateristics           = 0x400001
+//CHECK-NEXT:        IMAGE_SCN_ALIGN_8BYTES
+//CHECK-NEXT:      SectionData              = 
+//CHECK-NEXT:        00 00 00 00 90 90 90 90 - 00 00 00 00 00 00 00 00

diff --git a/test/MC/COFF/dg.exp b/test/MC/COFF/dg.exp
index 7b7bd4e73807cd29cc50e10343a052f9263c3978..d46d700975e5b4eaee15385102bd8331c8013ed9 100644 (file)
--- a/test/MC/COFF/dg.exp
+++ b/test/MC/COFF/dg.exp
@@ -1,5 +1,5 @@
 load_lib llvm.exp
 
 if { [llvm_supports_target X86] } {
-  RunLLVMTests [lsort [glob -nocomplain $srcdir/$subdir/*.{ll}]]
+  RunLLVMTests [lsort [glob -nocomplain $srcdir/$subdir/*.{ll,s}]]
 }

diff --git a/test/MC/ELF/align-nops.s b/test/MC/ELF/align-nops.s
new file mode 100644 (file)
index 0000000..b6793ec
--- /dev/null
+++ b/test/MC/ELF/align-nops.s
@@ -0,0 +1,40 @@
+// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | elf-dump --dump-section-data | FileCheck %s
+
+// Test that we get optimal nops in text
+    .text
+f0:
+    .long 0
+    .align  8, 0x90
+    .long 0
+    .align  8
+
+// But not in another section
+    .data
+    .long 0
+    .align  8, 0x90
+    .long 0
+    .align  8
+
+// CHECK: (('sh_name', 1) # '.text'
+// CHECK-NEXT:  ('sh_type', 1)
+// CHECK-NEXT:  ('sh_flags', 6)
+// CHECK-NEXT:  ('sh_addr',
+// CHECK-NEXT:  ('sh_offset',
+// CHECK-NEXT:  ('sh_size', 16)
+// CHECK-NEXT:  ('sh_link', 0)
+// CHECK-NEXT:  ('sh_info', 0)
+// CHECK-NEXT:  ('sh_addralign', 8)
+// CHECK-NEXT:  ('sh_entsize', 0)
+// CHECK-NEXT:  ('_section_data', '00000000 0f1f4000 00000000 0f1f4000')
+
+// CHECK: (('sh_name', 7) # '.data'
+// CHECK-NEXT:  ('sh_type', 1)
+// CHECK-NEXT:  ('sh_flags', 3)
+// CHECK-NEXT:  ('sh_addr',
+// CHECK-NEXT:  ('sh_offset',
+// CHECK-NEXT:  ('sh_size', 16)
+// CHECK-NEXT:  ('sh_link', 0)
+// CHECK-NEXT:  ('sh_info', 0)
+// CHECK-NEXT:  ('sh_addralign', 8)
+// CHECK-NEXT:  ('sh_entsize', 0)
+// CHECK-NEXT:  ('_section_data', '00000000 90909090 00000000 00000000')