[ThinLTO] Added a couple of C LTO API interfaces to control the cache policy.

- thinlto_codegen_set_cache_size_bytes to control the absolute size of cache directory. 
- thinlto_codegen_set_cache_size_files the size and amount of files in cache directory. 
These functions have been supported in C++ LTO API for a long time, but were absent in C LTO API.

Differential Revision: https://reviews.llvm.org/D42446

llvm-svn: 326537

Author: Ekaterina Romanova

llvm/include/llvm-c/lto.h

@@ -44,7 +44,7 @@ typedef bool lto_bool_t;
  * @{
  */
 
-#define LTO_API_VERSION 21
+#define LTO_API_VERSION 22
 
 /**
  * \since prior to LTO_API_VERSION=3
@@ -816,6 +816,28 @@ extern void thinlto_codegen_set_final_cache_size_relative_to_available_space(
 extern void thinlto_codegen_set_cache_entry_expiration(thinlto_code_gen_t cg,
                                                        unsigned expiration);
 
+/**
+ * Sets the maximum size of 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. An unspecified default value will be applied. A value of 0
+ * will be ignored.
+ *
+ * \since LTO_API_VERSION=22
+ */
+extern void thinlto_codegen_set_cache_size_bytes(thinlto_code_gen_t cg,
+                                                 unsigned max_size_bytes);
+
+/**
+ * Sets the maximum number of files in the cache directory. An unspecified
+ * default value will be applied. A value of 0 will be ignored.
+ *
+ * \since LTO_API_VERSION=22
+ */
+extern void thinlto_codegen_set_cache_size_files(thinlto_code_gen_t cg,
+                                                 unsigned max_size_files);
+
+
+
 /**
  * @} // endgroup LLVMCTLTO_CACHING
  */

llvm/include/llvm/LTO/legacy/ThinLTOCodeGenerator.h

@@ -184,6 +184,21 @@ class ThinLTOCodeGenerator {
       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

llvm/test/ThinLTO/X86/cache.ll

@@ -80,6 +80,40 @@
 ; RUN: llvm-lto -thinlto-action=run -exported-symbol=globalfunc %t2.bc %t.bc -thinlto-cache-dir %t.cache --thinlto-cache-pruning-interval 0
 ; RUN: not 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"
 

llvm/tools/llvm-lto/llvm-lto.cpp

@@ -160,6 +160,14 @@ static cl::opt<int>
     ThinLTOCachePruningInterval("thinlto-cache-pruning-interval",
     cl::init(1200), 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 "
@@ -475,6 +483,8 @@ class ThinLTOProcessing {
     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.

llvm/tools/lto/lto.cpp

@@ -586,6 +586,16 @@ void thinlto_codegen_set_final_cache_size_relative_to_available_space(
   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);

llvm/tools/lto/lto.exports

@@ -56,15 +56,17 @@ thinlto_codegen_set_pic_model
 thinlto_codegen_set_cache_dir
 thinlto_codegen_set_cache_pruning_interval
 thinlto_codegen_set_cache_entry_expiration
+thinlto_codegen_set_final_cache_size_relative_to_available_space
+thinlto_codegen_set_cache_size_bytes
+thinlto_codegen_set_cache_size_files
 thinlto_codegen_set_savetemps_dir
 thinlto_codegen_set_cpu
 thinlto_debug_options
 lto_module_is_thinlto
 thinlto_codegen_add_must_preserve_symbol
 thinlto_codegen_add_cross_referenced_symbol
-thinlto_codegen_set_final_cache_size_relative_to_available_space
 thinlto_codegen_set_codegen_only
 thinlto_codegen_disable_codegen
 thinlto_module_get_num_object_files
 thinlto_module_get_object_file
-thinlto_set_generated_objects_dir
+thinlto_set_generated_objects_dir