Index: include/llvm/LTO/legacy/ThinLTOCodeGenerator.h
===================================================================
--- include/llvm/LTO/legacy/ThinLTOCodeGenerator.h
+++ include/llvm/LTO/legacy/ThinLTOCodeGenerator.h
@@ -184,6 +184,21 @@
       CacheOptions.Policy.MaxSizePercentageOfAvailableSpace = Percentage;
   }
 
+  /// Cache policy: the maximum size for the cache directory in bytes. A value
+  /// over the amount of available space on the disk will be reduced to the
+  /// amount of available space. A value of 0 will be ignored.
+  void setCacheMaxSizeBytes(unsigned MaxSizeBytes) {
+    if (MaxSizeBytes)
+      CacheOptions.Policy.MaxSizeBytes = MaxSizeBytes;
+  }
+
+  /// Cache policy: the maximum number of files in the cache directory. A value
+  /// of 0 will be ignored.
+  void setCacheMaxSizeFiles(unsigned MaxSizeFiles) {
+    if (MaxSizeFiles)
+      CacheOptions.Policy.MaxSizeFiles = MaxSizeFiles;
+  }
+
   /**@}*/
 
   /// Set the path to a directory where to save temporaries at various stages of
Index: test/ThinLTO/X86/cache.ll
===================================================================
--- test/ThinLTO/X86/cache.ll
+++ test/ThinLTO/X86/cache.ll
@@ -59,6 +59,40 @@
 ; RUN: llvm-lto -thinlto-action=run -exported-symbol=globalfunc %t2.bc %t.bc -thinlto-cache-dir %t.cache --thinlto-cache-pruning-interval -1
 ; RUN: ls %t.cache/llvmcache-foo
 
+; Verify that specifying max size for the cache directory prunes it to this
+; size, removing the largest files first.
+; RUN: rm -Rf %t.cache && mkdir %t.cache
+; Create cache files with different sizes.
+; Only 8B, 16B and 76B files should stay after pruning.
+; RUN: %python -c "print(' ' * 1023)" > %t.cache/llvmcache-foo-1024
+; RUN: %python -c "print(' ' * 15)" > %t.cache/llvmcache-foo-16
+; RUN: %python -c "print(' ' * 7)" > %t.cache/llvmcache-foo-8
+; RUN: %python -c "print(' ' * 75)" > %t.cache/llvmcache-foo-76
+; RUN: %python -c "print(' ' * 76)" > %t.cache/llvmcache-foo-77
+; RUN: llvm-lto -thinlto-action=run -exported-symbol=globalfunc %t2.bc %t.bc -thinlto-cache-dir %t.cache --thinlto-cache-max-size-bytes 100
+; RUN: ls %t.cache/llvmcache-foo-16
+; RUN: ls %t.cache/llvmcache-foo-8
+; RUN: ls %t.cache/llvmcache-foo-76
+; RUN: not ls %t.cache/llvmcache-foo-1024
+; RUN: not ls %t.cache/llvmcache-foo-77
+
+; Verify that specifying max number of files in the cache directory prunes
+; it to this amount, removing the largest files first.
+; RUN: rm -Rf %t.cache && mkdir %t.cache
+; Create cache files with different sizes.
+; Only 8B and 16B files should stay after pruning.
+; RUN: %python -c "print(' ' * 1023)" > %t.cache/llvmcache-foo-1024
+; RUN: %python -c "print(' ' * 15)" > %t.cache/llvmcache-foo-16
+; RUN: %python -c "print(' ' * 7)" > %t.cache/llvmcache-foo-8
+; RUN: %python -c "print(' ' * 75)" > %t.cache/llvmcache-foo-76
+; RUN: %python -c "print(' ' * 76)" > %t.cache/llvmcache-foo-77
+; RUN: llvm-lto -thinlto-action=run -exported-symbol=globalfunc %t2.bc %t.bc -thinlto-cache-dir %t.cache --thinlto-cache-max-size-files 2
+; RUN: ls %t.cache/llvmcache-foo-16
+; RUN: ls %t.cache/llvmcache-foo-8
+; RUN: not ls %t.cache/llvmcache-foo-76
+; RUN: not ls %t.cache/llvmcache-foo-1024
+; RUN: not ls %t.cache/llvmcache-foo-77
+
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.11.0"
 
Index: tools/llvm-lto/llvm-lto.cpp
===================================================================
--- tools/llvm-lto/llvm-lto.cpp
+++ tools/llvm-lto/llvm-lto.cpp
@@ -159,6 +159,14 @@
 static cl::opt<int>
     ThinLTOCachePruningInterval("thinlto-cache-pruning-interval", cl::desc("Set ThinLTO cache pruning interval."));
 
+static cl::opt<int>
+    ThinLTOCacheMaxSizeBytes("thinlto-cache-max-size-bytes",
+    cl::desc("Set ThinLTO cache pruning directory maximum size in bytes."));
+
+static cl::opt<int>
+    ThinLTOCacheMaxSizeFiles("thinlto-cache-max-size-files", cl::init(1000000),
+    cl::desc("Set ThinLTO cache pruning directory maximum number of files."));
+
 static cl::opt<std::string> ThinLTOSaveTempsPrefix(
     "thinlto-save-temps",
     cl::desc("Save ThinLTO temp files using filenames created by adding "
@@ -474,6 +482,8 @@
     ThinGenerator.setTargetOptions(Options);
     ThinGenerator.setCacheDir(ThinLTOCacheDir);
     ThinGenerator.setCachePruningInterval(ThinLTOCachePruningInterval);
+    ThinGenerator.setCacheMaxSizeFiles(ThinLTOCacheMaxSizeFiles);
+    ThinGenerator.setCacheMaxSizeBytes(ThinLTOCacheMaxSizeBytes);
     ThinGenerator.setFreestanding(EnableFreestanding);
 
     // Add all the exported symbols to the table of symbols to preserve.
Index: tools/lto/lto.cpp
===================================================================
--- tools/lto/lto.cpp
+++ tools/lto/lto.cpp
@@ -586,6 +586,16 @@
   return unwrap(cg)->setMaxCacheSizeRelativeToAvailableSpace(Percentage);
 }
 
+void thinlto_codegen_set_cache_size_bytes(
+    thinlto_code_gen_t cg, unsigned MaxSizeBytes) {
+  return unwrap(cg)->setCacheMaxSizeBytes(MaxSizeBytes);
+}
+
+void thinlto_codegen_set_cache_size_files(
+    thinlto_code_gen_t cg, unsigned MaxSizeFiles) {
+  return unwrap(cg)->setCacheMaxSizeFiles(MaxSizeFiles);
+}
+
 void thinlto_codegen_set_savetemps_dir(thinlto_code_gen_t cg,
                                        const char *save_temps_dir) {
   return unwrap(cg)->setSaveTempsDir(save_temps_dir);