Bitcode: Write the irsymtab to disk.

Differential Revision: https://reviews.llvm.org/D33973

llvm-svn: 306487

llvm/include/llvm/Bitcode/BitcodeWriter.h

@@ -28,18 +28,34 @@ namespace llvm {
     std::unique_ptr<BitstreamWriter> Stream;
 
     StringTableBuilder StrtabBuilder{StringTableBuilder::RAW};
-    bool WroteStrtab = false;
+
+    // Owns any strings created by the irsymtab writer until we create the
+    // string table.
+    BumpPtrAllocator Alloc;
+
+    bool WroteStrtab = false, WroteSymtab = false;
 
     void writeBlob(unsigned Block, unsigned Record, StringRef Blob);
 
+    std::vector<Module *> Mods;
+
    public:
     /// Create a BitcodeWriter that writes to Buffer.
     BitcodeWriter(SmallVectorImpl<char> &Buffer);
 
     ~BitcodeWriter();
 
+    /// Attempt to write a symbol table to the bitcode file. This must be called
+    /// at most once after all modules have been written.
+    ///
+    /// A reader does not require a symbol table to interpret a bitcode file;
+    /// the symbol table is needed only to improve link-time performance. So
+    /// this function may decide not to write a symbol table. It may so decide
+    /// if, for example, the target is unregistered or the IR is malformed.
+    void writeSymtab();
+
     /// Write the bitcode file's string table. This must be called exactly once
-    /// after all modules have been written.
+    /// after all modules and the optional symbol table have been written.
     void writeStrtab();
 
     /// Copy the string table for another module into this bitcode file. This

llvm/include/llvm/Bitcode/LLVMBitCodes.h

@@ -22,7 +22,7 @@
 
 namespace llvm {
 namespace bitc {
-// The only top-level block types are MODULE, IDENTIFICATION and STRTAB.
+// The only top-level block types are MODULE, IDENTIFICATION, STRTAB and SYMTAB.
 enum BlockIDs {
   // Blocks
   MODULE_BLOCK_ID = FIRST_APPLICATION_BLOCKID,
@@ -57,6 +57,8 @@ enum BlockIDs {
   STRTAB_BLOCK_ID,
 
   FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
+
+  SYMTAB_BLOCK_ID,
 };
 
 /// Identification block contains a string that describes the producer details,
@@ -571,6 +573,10 @@ enum StrtabCodes {
   STRTAB_BLOB = 1,
 };
 
+enum SymtabCodes {
+  SYMTAB_BLOB = 1,
+};
+
 } // End bitc namespace
 } // End llvm namespace
 

llvm/lib/Bitcode/Writer/BitcodeWriter.cpp

@@ -29,10 +29,12 @@
 #include "llvm/IR/UseListOrder.h"
 #include "llvm/IR/ValueSymbolTable.h"
 #include "llvm/MC/StringTableBuilder.h"
+#include "llvm/Object/IRSymtab.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/Program.h"
 #include "llvm/Support/SHA1.h"
+#include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cctype>
 #include <map>
@@ -3820,6 +3822,38 @@ void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
   Stream->ExitBlock();
 }
 
+void BitcodeWriter::writeSymtab() {
+  assert(!WroteStrtab && !WroteSymtab);
+
+  // If any module has module-level inline asm, we will require a registered asm
+  // parser for the target so that we can create an accurate symbol table for
+  // the module.
+  for (Module *M : Mods) {
+    if (M->getModuleInlineAsm().empty())
+      continue;
+
+    std::string Err;
+    const Triple TT(M->getTargetTriple());
+    const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
+    if (!T || !T->hasMCAsmParser())
+      return;
+  }
+
+  WroteSymtab = true;
+  SmallVector<char, 0> Symtab;
+  // The irsymtab::build function may be unable to create a symbol table if the
+  // module is malformed (e.g. it contains an invalid alias). Writing a symbol
+  // table is not required for correctness, but we still want to be able to
+  // write malformed modules to bitcode files, so swallow the error.
+  if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
+    consumeError(std::move(E));
+    return;
+  }
+
+  writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
+            {Symtab.data(), Symtab.size()});
+}
+
 void BitcodeWriter::writeStrtab() {
   assert(!WroteStrtab);
 
@@ -3843,6 +3877,15 @@ void BitcodeWriter::writeModule(const Module *M,
                                 bool ShouldPreserveUseListOrder,
                                 const ModuleSummaryIndex *Index,
                                 bool GenerateHash, ModuleHash *ModHash) {
+  assert(!WroteStrtab);
+
+  // The Mods vector is used by irsymtab::build, which requires non-const
+  // Modules in case it needs to materialize metadata. But the bitcode writer
+  // requires that the module is materialized, so we can cast to non-const here,
+  // after checking that it is in fact materialized.
+  assert(M->isMaterialized());
+  Mods.push_back(const_cast<Module *>(M));
+
   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
                                    ShouldPreserveUseListOrder, Index,
                                    GenerateHash, ModHash);
@@ -3875,6 +3918,7 @@ void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
   BitcodeWriter Writer(Buffer);
   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
                      ModHash);
+  Writer.writeSymtab();
   Writer.writeStrtab();
 
   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())

llvm/lib/Object/CMakeLists.txt

@@ -27,4 +27,5 @@ add_llvm_library(LLVMObject
 
   DEPENDS
   intrinsics_gen
+  llvm_vcsrevision_h
   )

llvm/lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp

@@ -371,6 +371,7 @@ void splitAndWriteThinLTOBitcode(
                 /*GenerateHash=*/true, &ModHash);
   W.writeModule(MergedM.get(), /*ShouldPreserveUseListOrder=*/false,
                 &MergedMIndex);
+  W.writeSymtab();
   W.writeStrtab();
   OS << Buffer;
 
@@ -385,6 +386,7 @@ void splitAndWriteThinLTOBitcode(
                    /*GenerateHash=*/false, &ModHash);
     W2.writeModule(MergedM.get(), /*ShouldPreserveUseListOrder=*/false,
                    &MergedMIndex);
+    W2.writeSymtab();
     W2.writeStrtab();
     *ThinLinkOS << Buffer;
   }

llvm/test/Bitcode/thinlto-alias.ll

@@ -18,7 +18,7 @@
 ; CHECK-NEXT:  </GLOBALVAL_SUMMARY_BLOCK>
 
 ; CHECK: <STRTAB_BLOCK
-; CHECK-NEXT: blob data = 'mainanalias'
+; CHECK-NEXT: blob data = 'mainanalias{{.*}}'
 
 ; COMBINED:       <GLOBALVAL_SUMMARY_BLOCK
 ; COMBINED-NEXT:    <VERSION

llvm/test/Bitcode/thinlto-function-summary-callgraph-pgo.ll

@@ -20,7 +20,7 @@
 ; CHECK-NEXT:    <PERMODULE_PROFILE {{.*}} op4=1 op5=2/>
 ; CHECK-NEXT:  </GLOBALVAL_SUMMARY_BLOCK>
 ; CHECK: <STRTAB_BLOCK
-; CHECK-NEXT: blob data = 'mainfunc'
+; CHECK-NEXT: blob data = 'mainfunc{{.*}}'
 
 ; COMBINED:       <GLOBALVAL_SUMMARY_BLOCK
 ; COMBINED-NEXT:    <VERSION

llvm/test/Bitcode/thinlto-function-summary-callgraph-profile-summary.ll

@@ -33,7 +33,7 @@
 ; CHECK-NEXT:  </GLOBALVAL_SUMMARY_BLOCK>
 
 ; CHECK: <STRTAB_BLOCK
-; CHECK-NEXT: blob data = 'hot_functionhot1hot2hot3hot4coldnone1none2none3'
+; CHECK-NEXT: blob data = 'hot_functionhot1hot2hot3hot4coldnone1none2none3{{.*}}'
 
 ; COMBINED:       <GLOBALVAL_SUMMARY_BLOCK
 ; COMBINED-NEXT:    <VERSION

llvm/test/Bitcode/thinlto-function-summary-callgraph-sample-profile-summary.ll

@@ -33,7 +33,7 @@
 ; CHECK-NEXT:  </GLOBALVAL_SUMMARY_BLOCK>
 
 ; CHECK: <STRTAB_BLOCK
-; CHECK-NEXT: blob data = 'hot_functionhot1hot2hot3hot4coldnone1none2none3'
+; CHECK-NEXT: blob data = 'hot_functionhot1hot2hot3hot4coldnone1none2none3{{.*}}'
 
 ; COMBINED:       <GLOBALVAL_SUMMARY_BLOCK
 ; COMBINED-NEXT:    <VERSION

llvm/test/Bitcode/thinlto-function-summary-callgraph.ll

@@ -21,7 +21,7 @@
 ; CHECK-NEXT:    <PERMODULE {{.*}} op3=1
 ; CHECK-NEXT:  </GLOBALVAL_SUMMARY_BLOCK>
 ; CHECK: <STRTAB_BLOCK
-; CHECK-NEXT: blob data = 'undefinedglobmainfunc'
+; CHECK-NEXT: blob data = 'undefinedglobmainfunc{{.*}}'
 
 
 ; COMBINED:       <GLOBALVAL_SUMMARY_BLOCK

llvm/test/Bitcode/thinlto-function-summary-refgraph.ll

@@ -62,7 +62,7 @@
 ; CHECK:  </GLOBALVAL_SUMMARY_BLOCK>
 
 ; CHECK: <STRTAB_BLOCK
-; CHECK-NEXT: blob data = 'barglobalvarfuncfunc2foofunc3WXYZllvm.ctpop.i8main'
+; CHECK-NEXT: blob data = 'barglobalvarfuncfunc2foofunc3WXYZllvm.ctpop.i8main{{.*}}'
 
 ; ModuleID = 'thinlto-function-summary-refgraph.ll'
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"

llvm/test/Bitcode/thinlto-function-summary.ll

@@ -24,7 +24,7 @@
 ; BC-NEXT: <ALIAS {{.*}} op0=5 op1=0 op2=3
 ; BC-NEXT: </GLOBALVAL_SUMMARY_BLOCK
 ; BC: <STRTAB_BLOCK
-; BC-NEXT: blob data = 'hfoobaranon.{{................................}}.0variadicf'
+; BC-NEXT: blob data = 'hfoobaranon.{{................................}}.0variadicf{{.*}}'
 
 
 ; RUN: opt -name-anon-globals -module-summary < %s | llvm-dis | FileCheck %s

llvm/test/Object/X86/irsymtab-asm.ll

@@ -0,0 +1,17 @@
+; Check that we correctly handle the case where we have inline asm and the
+; target is not registered. In this case we shouldn't emit an irsymtab.
+
+; RUN: llvm-as -o %t %s
+; RUN: llvm-bcanalyzer -dump %t | FileCheck --check-prefix=AS %s
+
+; AS-NOT: <SYMTAB_BLOCK
+
+; RUN: opt -o %t2 %s
+; RUN: llvm-bcanalyzer -dump %t2 | FileCheck --check-prefix=OPT %s
+
+; OPT: <SYMTAB_BLOCK
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+module asm "ret"

llvm/test/Object/X86/irsymtab-bad-alias.ll

@@ -0,0 +1,15 @@
+; Check that we do not create an irsymtab for modules with malformed IR.
+
+; RUN: opt -o %t %s
+; RUN: llvm-bcanalyzer -dump %t | FileCheck %s
+
+; CHECK-NOT: <SYMTAB_BLOCK
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@g1 = global i32 1
+@g2 = global i32 2
+
+@a = alias i32, inttoptr(i32 sub (i32 ptrtoint (i32* @g1 to i32),
+                                  i32 ptrtoint (i32* @g2 to i32)) to i32*)

llvm/test/Object/X86/irsymtab.ll

@@ -0,0 +1,20 @@
+; RUN: env LLVM_OVERRIDE_PRODUCER=producer opt -o %t %s
+; RUN: llvm-bcanalyzer -dump -show-binary-blobs %t | FileCheck --check-prefix=BCA %s
+
+; BCA:      <SYMTAB_BLOCK
+; Version stored at offset 0.
+; BCA-NEXT:   <BLOB abbrevid=4/> blob data = '\x00\x00\x00\x00\x06\x00\x00\x00\x08\x00\x00\x00D\x00\x00\x00\x01\x00\x00\x00P\x00\x00\x00\x00\x00\x00\x00P\x00\x00\x00\x02\x00\x00\x00\x80\x00\x00\x00\x00\x00\x00\x00\x0E\x00\x00\x00\x18\x00\x00\x00&\x00\x00\x00\x0B\x00\x00\x001\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\xFF\xFF\xFF\xFF\x00$\x00\x00\x03\x00\x00\x00\x03\x00\x00\x00\x03\x00\x00\x00\x03\x00\x00\x00\xFF\xFF\xFF\xFF\x08$\x00\x00'
+; BCA-NEXT: </SYMTAB_BLOCK>
+; BCA-NEXT: <STRTAB_BLOCK
+; BCA-NEXT:   <BLOB abbrevid=4/> blob data = 'foobarproducerx86_64-unknown-linux-gnuirsymtab.ll'
+; BCA-NEXT: </STRTAB_BLOCK>
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+source_filename = "irsymtab.ll"
+
+define void @foo() {
+  ret void
+}
+
+declare void @bar()

llvm/test/ThinLTO/X86/autoupgrade.ll

@@ -10,7 +10,7 @@
 ; RUN:     | llvm-bcanalyzer -dump | FileCheck %s
 
 ; CHECK: <STRTAB_BLOCK
-; CHECK-NEXT: blob data = 'mainglobalfunc1llvm.invariant.start.p0i8'
+; CHECK-NEXT: blob data = 'mainglobalfunc1llvm.invariant.start.p0i8{{.*}}'
 
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.11.0"

llvm/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp

@@ -125,6 +125,7 @@ static const char *GetBlockName(unsigned BlockID,
                                       return "FULL_LTO_GLOBALVAL_SUMMARY_BLOCK";
   case bitc::MODULE_STRTAB_BLOCK_ID:       return "MODULE_STRTAB_BLOCK";
   case bitc::STRTAB_BLOCK_ID:              return "STRTAB_BLOCK";
+  case bitc::SYMTAB_BLOCK_ID:              return "SYMTAB_BLOCK";
   }
 }
 
@@ -393,6 +394,11 @@ static const char *GetCodeName(unsigned CodeID, unsigned BlockID,
     default: return nullptr;
     case bitc::STRTAB_BLOB: return "BLOB";
     }
+  case bitc::SYMTAB_BLOCK_ID:
+    switch(CodeID) {
+    default: return nullptr;
+    case bitc::SYMTAB_BLOB: return "BLOB";
+    }
   }
 #undef STRINGIFY_CODE
 }