[flang-commits] [flang] [flang] Use precompiled parsing headers (PR #130600)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-flang-driver

Author: Kajetan Puchalski (mrkajetanp)

<details>
<summary>Changes</summary>

Most of the high memory usage and compilation time in the frontend units is due to including large parsing headers.
This commit moves out several of the largest parsing headers into a new precompiled header linked to flangFrontend.
The new compilation metrics for FrontendActions.cpp are as follows:

User time (seconds): 38.40
System time (seconds): 2.00
Maximum resident set size (kbytes): 2710964 (2.58 GB) (vs 3.78 GB)

ParserActions.cpp:

User time (seconds): 69.37
System time (seconds): 1.81
Maximum resident set size (kbytes): 2599456 (2.47 GB) (vs 4 GB)

Alongside the new precompiled header compilation unit

User time (seconds): 41.61
System time (seconds): 2.72
Maximum resident set size (kbytes): 3107644 (2.96 GB)

---
Full diff: https://github.com/llvm/llvm-project/pull/130600.diff


4 Files Affected:

- (modified) flang/lib/Frontend/CMakeLists.txt (+8) 
- (modified) flang/lib/Frontend/CompilerInstance.cpp (-1) 
- (modified) flang/lib/Frontend/FrontendActions.cpp (-1) 
- (modified) flang/lib/Frontend/ParserActions.cpp (-4) 


``````````diff
diff --git a/flang/lib/Frontend/CMakeLists.txt b/flang/lib/Frontend/CMakeLists.txt
index c80373799b015..e8a098613e26f 100644
--- a/flang/lib/Frontend/CMakeLists.txt
+++ b/flang/lib/Frontend/CMakeLists.txt
@@ -72,3 +72,11 @@ add_flang_library(flangFrontend
   clangBasic
   clangDriver
 )
+
+target_precompile_headers(flangFrontend PRIVATE
+  [["flang/Parser/parsing.h"]]
+  [["flang/Parser/parse-tree.h"]]
+  [["flang/Parser/dump-parse-tree.h"]]
+  [["flang/Lower/PFTBuilder.h"]]
+  [["flang/Lower/Bridge.h"]]
+)
diff --git a/flang/lib/Frontend/CompilerInstance.cpp b/flang/lib/Frontend/CompilerInstance.cpp
index b1fa32ecb4cfc..5fd3b76b6741b 100644
--- a/flang/lib/Frontend/CompilerInstance.cpp
+++ b/flang/lib/Frontend/CompilerInstance.cpp
@@ -13,7 +13,6 @@
 #include "flang/Frontend/CompilerInstance.h"
 #include "flang/Frontend/CompilerInvocation.h"
 #include "flang/Frontend/TextDiagnosticPrinter.h"
-#include "flang/Parser/parsing.h"
 #include "flang/Parser/provenance.h"
 #include "flang/Semantics/semantics.h"
 #include "flang/Support/Fortran-features.h"
diff --git a/flang/lib/Frontend/FrontendActions.cpp b/flang/lib/Frontend/FrontendActions.cpp
index 94de376aaf7d6..cd3e206c19550 100644
--- a/flang/lib/Frontend/FrontendActions.cpp
+++ b/flang/lib/Frontend/FrontendActions.cpp
@@ -15,7 +15,6 @@
 #include "flang/Frontend/CompilerInvocation.h"
 #include "flang/Frontend/FrontendOptions.h"
 #include "flang/Frontend/ParserActions.h"
-#include "flang/Lower/Bridge.h"
 #include "flang/Lower/Support/Verifier.h"
 #include "flang/Optimizer/Dialect/Support/FIRContext.h"
 #include "flang/Optimizer/Dialect/Support/KindMapping.h"
diff --git a/flang/lib/Frontend/ParserActions.cpp b/flang/lib/Frontend/ParserActions.cpp
index cc7e72f696f96..7967832c80ac9 100644
--- a/flang/lib/Frontend/ParserActions.cpp
+++ b/flang/lib/Frontend/ParserActions.cpp
@@ -12,10 +12,6 @@
 
 #include "flang/Frontend/ParserActions.h"
 #include "flang/Frontend/CompilerInstance.h"
-#include "flang/Lower/Bridge.h"
-#include "flang/Lower/PFTBuilder.h"
-#include "flang/Parser/dump-parse-tree.h"
-#include "flang/Parser/parsing.h"
 #include "flang/Parser/provenance.h"
 #include "flang/Parser/source.h"
 #include "flang/Parser/unparse.h"

``````````

</details>


https://github.com/llvm/llvm-project/pull/130600