[DebugInfo] Support checksums in llvm-c bindings

[scott.linder]

Summary

The DIFile C++ API supports checksums, but the C-API does not. This patch updates the C-API to support an optional checksum value.

[probinson]

Do you have a use-case for the C API? We tend to update it only when necessary.
And when we do update it, it has to be backward-compatible IIUC. Adding new parameters to an existing API does not preserve that property.

[JDevlieghere]

In D43623#1016076, @probinson wrote:

Do you have a use-case for the C API? We tend to update it only when necessary.
And when we do update it, it has to be backward-compatible IIUC. Adding new parameters to an existing API does not preserve that property.

Exactly. I also vaguely remember that you'd have to bump some minor version somewhere?

[scott.linder]

I have no immediate use, I just did not understand that these APIs are only updated as-needed. I think it makes the most sense to abandon this patch and update the source-embedding patch to not touch the API, and if in the future it becomes useful to add either or both to the C API we can worry about how to retain backwards compatibility.

include/llvm-c/DebugInfo.h

  */
 typedef enum {
     LLVMDWARFEmissionNone = 0,
     LLVMDWARFEmissionFull,
     LLVMDWARFEmissionLineTablesOnly
 } LLVMDWARFEmissionKind;
 
 /**
+ * Which algorithm a checksum was generated with.
+ */
+typedef enum {
+  LLVMDIFileChecksumMD5 = 1,
+  LLVMDIFileChecksumSHA1 = 2,
+} LLVMDIFileChecksumKind;
+
+/**
  * The current debug metadata version number.
  */
 unsigned LLVMDebugMetadataVersion(void);
 
 /**
  * The version of debug metadata that's present in the provided \c Module.
  */
 unsigned LLVMGetModuleDebugMetadataVersion(LLVMModuleRef Module);

  * \param Filename     File name.
  * \param FilenameLen  The length of the C string passed to \c Filename.
  * \param Directory    Directory.
  * \param DirectoryLen The length of the C string passed to \c Directory.
  */
 LLVMMetadataRef
 LLVMDIBuilderCreateFile(LLVMDIBuilderRef Builder, const char *Filename,
                         size_t FilenameLen, const char *Directory,
-                        size_t DirectoryLen);
+                        size_t DirectoryLen, LLVMBool ChecksumPresent,
+                        LLVMDIFileChecksumKind ChecksumKind,
+                        const char *Checksum, size_t ChecksumLen);
 
 /**
  * Creates a new DebugLocation that describes a source location.
  * \param Line The line in the source file.
  * \param Column The column in the source file.
  * \param Scope The scope in which the location resides.
  * \param InlinedAt The scope where this location was inlined, if at all.
  *                  (optional).

lib/IR/DebugInfo.cpp

 // information in LLVM IR form.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm-c/DebugInfo.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/None.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/DebugLoc.h"
return wrap(unwrap(Builder)->createCompileUnit(
                  StringRef(SplitName, SplitNameLen),
                  static_cast<DICompileUnit::DebugEmissionKind>(Kind), DWOId,
                  SplitDebugInlining, DebugInfoForProfiling));
 }
 
 LLVMMetadataRef
 LLVMDIBuilderCreateFile(LLVMDIBuilderRef Builder, const char *Filename,
                         size_t FilenameLen, const char *Directory,
-                        size_t DirectoryLen) {
+                        size_t DirectoryLen, LLVMBool ChecksumPresent,
+                        LLVMDIFileChecksumKind ChecksumKind,
+                        const char *Checksum, size_t ChecksumLen) {
+  Optional<DIFile::ChecksumInfo<StringRef>> OptChecksum;
+  if (ChecksumPresent)
+    OptChecksum.emplace(static_cast<DIFile::ChecksumKind>(ChecksumKind),
+                        StringRef(Checksum, ChecksumLen));
   return wrap(unwrap(Builder)->createFile(StringRef(Filename, FilenameLen),
-                                          StringRef(Directory, DirectoryLen)));
+                                          StringRef(Directory, DirectoryLen),
+                                          OptChecksum));
 }
 
 LLVMMetadataRef
 LLVMDIBuilderCreateDebugLocation(LLVMContextRef Ctx, unsigned Line,
                                  unsigned Column, LLVMMetadataRef Scope,
                                  LLVMMetadataRef InlinedAt) {
   return wrap(DILocation::get(*unwrap(Ctx), Line, Column, unwrap(Scope),
                               unwrap(InlinedAt)));
 }

test/Bindings/llvm-c/debug_info.ll

 ; RUN: llvm-c-test --test-dibuilder | FileCheck %s
 
 ; CHECK: ; ModuleID = 'debuginfo.c'
 ; CHECK-NEXT: source_filename = "debuginfo.c"
 
-; CHECK: !llvm.dbg.cu = !{!0}
+; CHECK: !llvm.dbg.cu = !{!0, !2}
 ; CHECK: !0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "llvm-c-test", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false)
-; CHECK-NEXT: !1 = !DIFile(filename: "debuginfo.c\00", directory: ".")
+; CHECK-NEXT: !1 = !DIFile(filename: "debuginfo.c", directory: ".")
+; CHECK: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "llvm-c-test", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false)
+; CHECK-NEXT: !3 = !DIFile(filename: "a.h", directory: ".", checksumkind: CSK_MD5, checksum: "595f44fec1e92a71d3e9e77456ba80d1")

tools/llvm-c-test/debuginfo.c

 
 #include "llvm-c/DebugInfo.h"
 #include <stdio.h>
 
 int llvm_test_dibuilder(void) {
   LLVMModuleRef M = LLVMModuleCreateWithName("debuginfo.c");
   LLVMDIBuilderRef DIB = LLVMCreateDIBuilder(M);
 
-  LLVMMetadataRef File = LLVMDIBuilderCreateFile(DIB, "debuginfo.c", 12,
-                                                 ".", 1);
+  LLVMMetadataRef File =
+      LLVMDIBuilderCreateFile(DIB, "debuginfo.c", 11, ".", 1, 0, 0, NULL, 0);
 
   LLVMDIBuilderCreateCompileUnit(DIB,
       LLVMDWARFSourceLanguageC, File,"llvm-c-test", 11, 0, NULL, 0, 0,
       NULL, 0, LLVMDWARFEmissionFull, 0, 0, 0);
 
+  LLVMMetadataRef FileWithChecksum = LLVMDIBuilderCreateFile(
+      DIB, "a.h", 3, ".", 1, 1, LLVMDIFileChecksumMD5,
+      "595f44fec1e92a71d3e9e77456ba80d1", 32);
+
+  LLVMDIBuilderCreateCompileUnit(DIB,
+      LLVMDWARFSourceLanguageC, FileWithChecksum, "llvm-c-test", 11, 0, NULL, 0, 0,
+      NULL, 0, LLVMDWARFEmissionFull, 0, 0, 0);
+
   char *MStr = LLVMPrintModuleToString(M);
   puts(MStr);
   LLVMDisposeMessage(MStr);
 
   LLVMDisposeDIBuilder(DIB);
   LLVMDisposeModule(M);
 
   return 0;
 }