[PATCH] D124792: [ifs] Add --strip-size flag

[Alex Brachet via Phabricator via llvm-commits]

abrachet created this revision.
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st_size may not be of importance to the abi if you are not using copy relocations. This is helpful when you want to check the abi of a shared object both when instrumented and not because asan will increase the size of objects to include the redzone.


https://reviews.llvm.org/D124792

Files:
  llvm/lib/InterfaceStub/ELFObjHandler.cpp
  llvm/lib/InterfaceStub/IFSHandler.cpp
  llvm/test/tools/llvm-ifs/strip-size.test
  llvm/tools/llvm-ifs/llvm-ifs.cpp


Index: llvm/tools/llvm-ifs/llvm-ifs.cpp
===================================================================
--- llvm/tools/llvm-ifs/llvm-ifs.cpp
+++ llvm/tools/llvm-ifs/llvm-ifs.cpp
@@ -107,6 +107,10 @@
 cl::opt<bool> StripNeededLibs("strip-needed",
                               cl::desc("Strip needed libs from output"),
                               cl::cat(IfsCategory));
+cl::opt<bool> StripSize("strip-size",
+                        cl::desc("Remove object size from the output"),
+                        cl::cat(IfsCategory));
+
 cl::list<std::string>
     ExcludeSyms("exclude",
                 cl::desc("Remove symbols which match the pattern. Can be "
@@ -432,6 +436,10 @@
   if (Error E = filterIFSSyms(Stub, StripUndefined, ExcludeSyms))
     fatalError(std::move(E));
 
+  if (StripSize)
+    for (auto &Sym : Stub.Symbols)
+      Sym.Size = std::numeric_limits<uint64_t>::max();
+
   if (OutputELFFilePath.getNumOccurrences() == 0 &&
       OutputIFSFilePath.getNumOccurrences() == 0 &&
       OutputTBDFilePath.getNumOccurrences() == 0) {
Index: llvm/test/tools/llvm-ifs/strip-size.test
===================================================================
--- /dev/null
+++ llvm/test/tools/llvm-ifs/strip-size.test
@@ -0,0 +1,20 @@
+# RUN: llvm-ifs %s --output-ifs - --strip-size | FileCheck %s
+
+# CHECK:      Symbols:
+# CHECK-NEXT:   - { Name: sym, Type: Object }
+# CHECK-NEXT: ...
+
+## Check that the size when emitting to elf defaults to 1
+# RUN: llvm-ifs %s --output-elf - --strip-size | llvm-ifs - --output-ifs - | \
+# RUN:   FileCheck %s --check-prefix=ELF
+
+# ELF:      Symbols:
+# ELF-NEXT:   - { Name: sym, Type: Object, Size: 1 }
+# ELF-NEXT: ...
+
+--- !ifs-v1
+IfsVersion: 3.0
+Target: x86_64
+Symbols:
+  - { Name: sym, Type: Object, Size: 2 }
+...
Index: llvm/lib/InterfaceStub/IFSHandler.cpp
===================================================================
--- llvm/lib/InterfaceStub/IFSHandler.cpp
+++ llvm/lib/InterfaceStub/IFSHandler.cpp
@@ -119,9 +119,8 @@
     // The need for symbol size depends on the symbol type.
     if (Symbol.Type == IFSSymbolType::NoType) {
       IO.mapOptional("Size", Symbol.Size, (uint64_t)0);
-    } else if (Symbol.Type == IFSSymbolType::Func) {
-      Symbol.Size = 0;
-    } else {
+    } else if (Symbol.Type != IFSSymbolType::Func &&
+               Symbol.Size != std::numeric_limits<uint64_t>::max()) {
       IO.mapRequired("Size", Symbol.Size);
     }
     IO.mapOptional("Undefined", Symbol.Undefined, false);
Index: llvm/lib/InterfaceStub/ELFObjHandler.cpp
===================================================================
--- llvm/lib/InterfaceStub/ELFObjHandler.cpp
+++ llvm/lib/InterfaceStub/ELFObjHandler.cpp
@@ -217,7 +217,10 @@
       // time as long as it is not SHN_UNDEF. Set shndx to 1, which
       // points to ".dynsym".
       uint16_t Shndx = Sym.Undefined ? SHN_UNDEF : 1;
-      DynSym.Content.add(DynStr.Content.getOffset(Sym.Name), Sym.Size, Bind,
+      uint64_t Size = Sym.Size;
+      if (Size == std::numeric_limits<uint64_t>::max())
+        Size = 1;
+      DynSym.Content.add(DynStr.Content.getOffset(Sym.Name), Size, Bind,
                          convertIFSSymbolTypeToELF(Sym.Type), 0, Shndx);
     }
     DynSym.Size = DynSym.Content.getSize();


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