Add support for reading members out of thin archives.

For now the Archive owns the buffers of the thin archive members.
This makes for a simple API, but all the buffers are destructed
only when the archive is destructed. This should be fine since we
close the files after mmap so we should not hit an open file
limit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242215 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Object/Archive.h b/include/llvm/Object/Archive.h
index e461564ace8e092b9a5edd9fed9d9b1af1555ecd..597f0d48c118d6c218156909d9f4b45f966288ae 100644 (file)
--- a/include/llvm/Object/Archive.h
+++ b/include/llvm/Object/Archive.h
@@ -94,9 +94,7 @@ public:
     /// \return the size in the archive header for this member.
     uint64_t getRawSize() const;
 
-    StringRef getBuffer() const {
-      return StringRef(Data.data() + StartOfFile, getSize());
-    }
+    ErrorOr<StringRef> getBuffer() const;
     uint64_t getChildOffset() const;
 
     ErrorOr<MemoryBufferRef> getMemoryBufferRef() const;
@@ -208,7 +206,11 @@ public:
 
   bool hasSymbolTable() const;
   child_iterator getSymbolTableChild() const { return SymbolTable; }
-  StringRef getSymbolTable() const { return SymbolTable->getBuffer(); }
+  StringRef getSymbolTable() const {
+    // We know that the symbol table is not an external file,
+    // so we just assert there is no error.
+    return *SymbolTable->getBuffer();
+  }
   uint32_t getNumberOfSymbols() const;
 
 private:
@@ -217,6 +219,7 @@ private:
   child_iterator FirstRegular;
   unsigned Format : 2;
   unsigned IsThin : 1;
+  mutable std::vector<std::unique_ptr<MemoryBuffer>> ThinBuffers;
 };
 
 }

diff --git a/lib/Object/Archive.cpp b/lib/Object/Archive.cpp
index c29e63941f29b70b9b000ddc7290e4b0bea36c5e..d4821196a6cf86a2de0dad1d43a5daeaf9b7be5f 100644 (file)
--- a/lib/Object/Archive.cpp
+++ b/lib/Object/Archive.cpp
@@ -17,6 +17,7 @@
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Path.h"
 
 using namespace llvm;
 using namespace object;
@@ -115,6 +116,23 @@ uint64_t Archive::Child::getRawSize() const {
   return getHeader()->getSize();
 }
 
+ErrorOr<StringRef> Archive::Child::getBuffer() const {
+  if (!Parent->IsThin)
+    return StringRef(Data.data() + StartOfFile, getSize());
+  ErrorOr<StringRef> Name = getName();
+  if (std::error_code EC = Name.getError())
+    return EC;
+  SmallString<128> FullName =
+      Parent->getMemoryBufferRef().getBufferIdentifier();
+  sys::path::remove_filename(FullName);
+  sys::path::append(FullName, *Name);
+  ErrorOr<std::unique_ptr<MemoryBuffer>> Buf = MemoryBuffer::getFile(FullName);
+  if (std::error_code EC = Buf.getError())
+    return EC;
+  Parent->ThinBuffers.push_back(std::move(*Buf));
+  return Parent->ThinBuffers.back()->getBuffer();
+}
+
 Archive::Child Archive::Child::getNext() const {
   size_t SpaceToSkip = Data.size();
   // If it's odd, add 1 to make it even.
@@ -186,7 +204,10 @@ ErrorOr<MemoryBufferRef> Archive::Child::getMemoryBufferRef() const {
   if (std::error_code EC = NameOrErr.getError())
     return EC;
   StringRef Name = NameOrErr.get();
-  return MemoryBufferRef(getBuffer(), Name);
+  ErrorOr<StringRef> Buf = getBuffer();
+  if (std::error_code EC = Buf.getError())
+    return EC;
+  return MemoryBufferRef(*Buf, Name);
 }
 
 ErrorOr<std::unique_ptr<Binary>>

diff --git a/test/Object/archive-extract.test b/test/Object/archive-extract.test
index c1ddcf717257aa7e0a62ab2fad5b10821994f0b5..a77adf2cabbd0e0e425ea3a1653f1e040063deba 100644 (file)
--- a/test/Object/archive-extract.test
+++ b/test/Object/archive-extract.test
@@ -48,3 +48,9 @@ NOTFOUND: foo.o was not found
 
 RUN: not llvm-ar x %p/Inputs/thin.a foo.o 2>&1 | FileCheck %s --check-prefix=THINEXTRACT
 THINEXTRACT: extracting from a thin archive is not supported
+
+RUN: llvm-ar p %p/Inputs/thin.a evenlen | FileCheck %s --check-prefix=EVENLEN
+EVENLEN: evenlen
+
+RUN: not llvm-ar p %p/Inputs/thin-path.a t/test2.o | FileCheck %s --check-prefix=MISSING
+MISSING: No such file or directory.

diff --git a/tools/llvm-ar/llvm-ar.cpp b/tools/llvm-ar/llvm-ar.cpp
index c87606d7826891162ccdfdec3637338b4aac0402..2c9668c63b8cc18fcc3f0e2b6298d0439433523b 100644 (file)
--- a/tools/llvm-ar/llvm-ar.cpp
+++ b/tools/llvm-ar/llvm-ar.cpp
@@ -299,7 +299,9 @@ static void doPrint(StringRef Name, const object::Archive::Child &C) {
   if (Verbose)
     outs() << "Printing " << Name << "\n";
 
-  StringRef Data = C.getBuffer();
+  ErrorOr<StringRef> DataOrErr = C.getBuffer();
+  failIfError(DataOrErr.getError());
+  StringRef Data = *DataOrErr;
   outs().write(Data.data(), Data.size());
 }
 
@@ -355,7 +357,7 @@ static void doExtract(StringRef Name, const object::Archive::Child &C) {
     raw_fd_ostream file(FD, false);
 
     // Get the data and its length
-    StringRef Data = C.getBuffer();
+    StringRef Data = *C.getBuffer();
 
     // Write the data.
     file.write(Data.data(), Data.size());