llvm-cov: Split GCOVFile's read into GCNO and GCDA.

This splits the file-scope read() function into readGCNO() and
readGCDA(). Also broke file format read into functions that first read
the file type, then check the version.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196353 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 105 insertions, 79 deletions

diff --git a/include/llvm/Support/GCOV.h b/include/llvm/Support/GCOV.h
index 9aa44139f0..d80913717a 100644
--- a/include/llvm/Support/GCOV.h
+++ b/include/llvm/Support/GCOV.h
@@ -28,12 +28,9 @@ class GCOVBlock;
 class FileInfo;
 
 namespace GCOV {
-  enum GCOVFormat {
-    InvalidGCOV,
-    GCNO_402,
-    GCNO_404,
-    GCDA_402,
-    GCDA_404
+  enum GCOVVersion {
+    V402,
+    V404
   };
 } // end GCOV namespace
 
@@ -43,21 +40,43 @@ class GCOVBuffer {
 public:
   GCOVBuffer(MemoryBuffer *B) : Buffer(B), Cursor(0) {}
   
-  /// readGCOVFormat - Read GCOV signature at the beginning of buffer.
-  GCOV::GCOVFormat readGCOVFormat() {
-    StringRef Magic = Buffer->getBuffer().slice(0, 8);
-    Cursor = 8;
-    if (Magic == "oncg*404")
-      return GCOV::GCNO_404;
-    else if (Magic == "oncg*204")
-      return GCOV::GCNO_402;
-    else if (Magic == "adcg*404")
-      return GCOV::GCDA_404;
-    else if (Magic == "adcg*204")
-      return GCOV::GCDA_402;
-    
-    Cursor = 0;
-    return GCOV::InvalidGCOV;
+  /// readGCNOFormat - Check GCNO signature is valid at the beginning of buffer.
+  bool readGCNOFormat() {
+    StringRef File = Buffer->getBuffer().slice(0, 4);
+    if (File != "oncg") {
+      errs() << "Unexpected file type: " << File << ".\n";
+      return false;
+    }
+    Cursor = 4;
+    return true;
+  }
+
+  /// readGCDAFormat - Check GCDA signature is valid at the beginning of buffer.
+  bool readGCDAFormat() {
+    StringRef File = Buffer->getBuffer().slice(0, 4);
+    if (File != "adcg") {
+      errs() << "Unexpected file type: " << File << ".\n";
+      return false;
+    }
+    Cursor = 4;
+    return true;
+  }
+
+  /// readGCOVVersion - Read GCOV version.
+  bool readGCOVVersion(GCOV::GCOVVersion &Version) {
+    StringRef VersionStr = Buffer->getBuffer().slice(Cursor, Cursor+4);
+    if (VersionStr == "*204") {
+      Cursor += 4;
+      Version = GCOV::V402;
+      return true;
+    }
+    if (VersionStr == "*404") {
+      Cursor += 4;
+      Version = GCOV::V404;
+      return true;
+    }
+    errs() << "Unexpected version: " << VersionStr << ".\n";
+    return false;
   }
 
   /// readFunctionTag - If cursor points to a function tag then increment the
@@ -193,12 +212,16 @@ private:
 /// (.gcno and .gcda).
 class GCOVFile {
 public:
-  GCOVFile() : Checksum(0), Functions(), RunCount(0), ProgramCount(0) {}
+  GCOVFile() : gcnoInitialized(false), Checksum(0), Functions(), RunCount(0),
+               ProgramCount(0) {}
   ~GCOVFile();
-  bool read(GCOVBuffer &Buffer);
+  bool readGCNO(GCOVBuffer &Buffer);
+  bool readGCDA(GCOVBuffer &Buffer);
   void dump() const;
   void collectLineCounts(FileInfo &FI);
 private:
+  bool gcnoInitialized;
+  GCOV::GCOVVersion Version;
   uint32_t Checksum;
   SmallVector<GCOVFunction *, 16> Functions;
   uint32_t RunCount;
@@ -218,8 +241,8 @@ class GCOVFunction {
 public:
   GCOVFunction() : Ident(0), LineNumber(0) {}
   ~GCOVFunction();
-  bool readGCNO(GCOVBuffer &Buffer, GCOV::GCOVFormat Format);
-  bool readGCDA(GCOVBuffer &Buffer, GCOV::GCOVFormat Format);
+  bool readGCNO(GCOVBuffer &Buffer, GCOV::GCOVVersion Version);
+  bool readGCDA(GCOVBuffer &Buffer, GCOV::GCOVVersion Version);
   StringRef getFilename() const { return Filename; }
   void dump() const;
   void collectLineCounts(FileInfo &FI);
diff --git a/lib/IR/GCOV.cpp b/lib/IR/GCOV.cpp
index 8ce93675e4..3b870f3471 100644
--- a/lib/IR/GCOV.cpp
+++ b/lib/IR/GCOV.cpp
@@ -29,61 +29,64 @@ GCOVFile::~GCOVFile() {
   DeleteContainerPointers(Functions);
 }
 
-/// isGCDAFile - Return true if Format identifies a .gcda file.
-static bool isGCDAFile(GCOV::GCOVFormat Format) {
-  return Format == GCOV::GCDA_402 || Format == GCOV::GCDA_404;
-}
+/// readGCNO - Read GCNO buffer.
+bool GCOVFile::readGCNO(GCOVBuffer &Buffer) {
+  if (!Buffer.readGCNOFormat()) return false;
+  if (!Buffer.readGCOVVersion(Version)) return false;
+
+  if (!Buffer.readInt(Checksum)) return false;
+  while (true) {
+    if (!Buffer.readFunctionTag()) break;
+    GCOVFunction *GFun = new GCOVFunction();
+    if (!GFun->readGCNO(Buffer, Version))
+      return false;
+    Functions.push_back(GFun);
+  }
 
-/// isGCNOFile - Return true if Format identifies a .gcno file.
-static bool isGCNOFile(GCOV::GCOVFormat Format) {
-  return Format == GCOV::GCNO_402 || Format == GCOV::GCNO_404;
+  gcnoInitialized = true;
+  return true;
 }
 
-/// read - Read GCOV buffer.
-bool GCOVFile::read(GCOVBuffer &Buffer) {
-  GCOV::GCOVFormat Format = Buffer.readGCOVFormat();
-  if (Format == GCOV::InvalidGCOV)
+/// readGCDA - Read GCDA buffer. It is required that readGCDA() can only be
+/// called after readGCNO().
+bool GCOVFile::readGCDA(GCOVBuffer &Buffer) {
+  assert(gcnoInitialized && "readGCDA() can only be called after readGCNO()");
+  if (!Buffer.readGCDAFormat()) return false;
+  GCOV::GCOVVersion GCDAVersion;
+  if (!Buffer.readGCOVVersion(GCDAVersion)) return false;
+  if (Version != GCDAVersion) {
+    errs() << "GCOV versions do not match.\n";
     return false;
+  }
 
-  if (isGCNOFile(Format)) {
-    if (!Buffer.readInt(Checksum)) return false;
-    while (true) {
-      if (!Buffer.readFunctionTag()) break;
-      GCOVFunction *GFun = new GCOVFunction();
-      if (!GFun->readGCNO(Buffer, Format))
-        return false;
-      Functions.push_back(GFun);
-    }
-  } else if (isGCDAFile(Format)) {
-    uint32_t Checksum2;
-    if (!Buffer.readInt(Checksum2)) return false;
-    if (Checksum != Checksum2) {
-      errs() << "File checksum does not match.\n";
+  uint32_t GCDAChecksum;
+  if (!Buffer.readInt(GCDAChecksum)) return false;
+  if (Checksum != GCDAChecksum) {
+    errs() << "File checksum does not match.\n";
+    return false;
+  }
+  for (size_t i = 0, e = Functions.size(); i < e; ++i) {
+    if (!Buffer.readFunctionTag()) {
+      errs() << "Unexpected number of functions.\n";
       return false;
     }
-    for (size_t i = 0, e = Functions.size(); i < e; ++i) {
-      if (!Buffer.readFunctionTag()) {
-        errs() << "Unexpected number of functions.\n";
-        return false;
-      }
-      if (!Functions[i]->readGCDA(Buffer, Format))
-        return false;
-    }
-    if (Buffer.readObjectTag()) {
-      uint32_t Length;
-      uint32_t Dummy;
-      if (!Buffer.readInt(Length)) return false;
-      if (!Buffer.readInt(Dummy)) return false; // checksum
-      if (!Buffer.readInt(Dummy)) return false; // num
-      if (!Buffer.readInt(RunCount)) return false;;
-      Buffer.advanceCursor(Length-3);
-    }
-    while (Buffer.readProgramTag()) {
-      uint32_t Length;
-      if (!Buffer.readInt(Length)) return false;
-      Buffer.advanceCursor(Length);
-      ++ProgramCount;
-    }
+    if (!Functions[i]->readGCDA(Buffer, Version))
+      return false;
+  }
+  if (Buffer.readObjectTag()) {
+    uint32_t Length;
+    uint32_t Dummy;
+    if (!Buffer.readInt(Length)) return false;
+    if (!Buffer.readInt(Dummy)) return false; // checksum
+    if (!Buffer.readInt(Dummy)) return false; // num
+    if (!Buffer.readInt(RunCount)) return false;;
+    Buffer.advanceCursor(Length-3);
+  }
+  while (Buffer.readProgramTag()) {
+    uint32_t Length;
+    if (!Buffer.readInt(Length)) return false;
+    Buffer.advanceCursor(Length);
+    ++ProgramCount;
   }
 
   return true;
@@ -117,12 +120,12 @@ GCOVFunction::~GCOVFunction() {
 
 /// readGCNO - Read a function from the GCNO buffer. Return false if an error
 /// occurs.
-bool GCOVFunction::readGCNO(GCOVBuffer &Buff, GCOV::GCOVFormat Format) {
+bool GCOVFunction::readGCNO(GCOVBuffer &Buff, GCOV::GCOVVersion Version) {
   uint32_t Dummy;
   if (!Buff.readInt(Dummy)) return false; // Function header length
   if (!Buff.readInt(Ident)) return false;
   if (!Buff.readInt(Dummy)) return false; // Checksum #1
-  if (Format != GCOV::GCNO_402)
+  if (Version != GCOV::V402)
     if (!Buff.readInt(Dummy)) return false; // Checksum #2
 
   if (!Buff.readString(Name)) return false;
@@ -198,12 +201,12 @@ bool GCOVFunction::readGCNO(GCOVBuffer &Buff, GCOV::GCOVFormat Format) {
 
 /// readGCDA - Read a function from the GCDA buffer. Return false if an error
 /// occurs.
-bool GCOVFunction::readGCDA(GCOVBuffer &Buff, GCOV::GCOVFormat Format) {
+bool GCOVFunction::readGCDA(GCOVBuffer &Buff, GCOV::GCOVVersion Version) {
   uint32_t Dummy;
   if (!Buff.readInt(Dummy)) return false; // Function header length
   if (!Buff.readInt(Ident)) return false;
   if (!Buff.readInt(Dummy)) return false; // Checksum #1
-  if (Format != GCOV::GCDA_402)
+  if (Version != GCOV::V402)
     if (!Buff.readInt(Dummy)) return false; // Checksum #2
 
   if (!Buff.readString(Name)) return false;
diff --git a/tools/llvm-cov/llvm-cov.cpp b/tools/llvm-cov/llvm-cov.cpp
index 7f4d53e848..b1ea33e4bd 100644
--- a/tools/llvm-cov/llvm-cov.cpp
+++ b/tools/llvm-cov/llvm-cov.cpp
@@ -49,7 +49,7 @@ int main(int argc, char **argv) {
     return 1;
   }
   GCOVBuffer GCNO_GB(GCNO_Buff.get());
-  if (!GF.read(GCNO_GB)) {
+  if (!GF.readGCNO(GCNO_GB)) {
     errs() << "Invalid .gcno File!\n";
     return 1;
   }
@@ -61,7 +61,7 @@ int main(int argc, char **argv) {
       return 1;
     }
     GCOVBuffer GCDA_GB(GCDA_Buff.get());
-    if (!GF.read(GCDA_GB)) {
+    if (!GF.readGCDA(GCDA_GB)) {
       errs() << "Invalid .gcda File!\n";
       return 1;
     }