[clang] e8f721e - [clang][docs] Update doc and release note for probe instrumentation (#162606)
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Mon Oct 13 18:02:47 PDT 2025
Author: Haohai Wen
Date: 2025-10-14T09:02:43+08:00
New Revision: e8f721e621d85a2670f13307b1b99528cf5e8708
URL: https://github.com/llvm/llvm-project/commit/e8f721e621d85a2670f13307b1b99528cf5e8708
DIFF: https://github.com/llvm/llvm-project/commit/e8f721e621d85a2670f13307b1b99528cf5e8708.diff
LOG: [clang][docs] Update doc and release note for probe instrumentation (#162606)
-fpseudo-probe-for-profiling is supported for COFF in #123870.
llvm-profgen supports decoding pseudo probe in #158207.
This PR updates release note and adds an example to use it in
UsersManual.rst.
Added:
Modified:
clang/docs/UsersManual.rst
llvm/docs/ReleaseNotes.md
Removed:
################################################################################
diff --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst
index 2d1048975faef..01f0b27846f0b 100644
--- a/clang/docs/UsersManual.rst
+++ b/clang/docs/UsersManual.rst
@@ -2780,6 +2780,25 @@ usual build cycle when using sample profilers for optimization:
/clang:-fdebug-info-for-profiling /clang:-funique-internal-linkage-names ^
code.cc /Fe:code -fuse-ld=lld /link /debug:dwarf
+ [OPTIONAL] Pseudo instrumentation can be used as the anchor for accurate
+ profile mapping with the ``-fpseudo-probe-for-profiling`` option.
+
+ On Linux:
+
+ .. code-block:: console
+
+ $ clang++ -O2 -gline-tables-only \
+ -fpseudo-probe-for-profiling -funique-internal-linkage-names \
+ code.cc -o code
+
+ On Windows:
+
+ .. code-block:: winbatch
+
+ > clang-cl /O2 -gdwarf -gline-tables-only ^
+ -fpseudo-probe-for-profiling /clang:-funique-internal-linkage-names ^
+ code.cc /Fe:code -fuse-ld=lld /link /debug:dwarf
+
.. note::
:ref:`-funique-internal-linkage-names <funique_internal_linkage_names>`
@@ -2881,6 +2900,25 @@ usual build cycle when using sample profilers for optimization:
/clang:-fdebug-info-for-profiling /clang:-funique-internal-linkage-names ^
-fprofile-sample-use=code.prof code.cc /Fe:code
+ [OPTIONAL] Pseudo instrumentation can be used as the anchor for accurate
+ profile mapping with the ``-fpseudo-probe-for-profiling`` option.
+
+ On Linux:
+
+ .. code-block:: console
+
+ $ clang++ -O2 \
+ -fpseudo-probe-for-profiling -funique-internal-linkage-names \
+ -fprofile-sample-use=code.prof code.cc -o code
+
+ On Windows:
+
+ .. code-block:: winbatch
+
+ > clang-cl /O2 ^
+ -fpseudo-probe-for-profiling /clang:-funique-internal-linkage-names ^
+ -fprofile-sample-use=code.prof code.cc /Fe:code
+
[OPTIONAL] Sampling-based profiles can have inaccuracies or missing block/
edge counters. The profile inference algorithm (profi) can be used to infer
missing blocks and edge counts, and improve the quality of profile data.
diff --git a/llvm/docs/ReleaseNotes.md b/llvm/docs/ReleaseNotes.md
index 46a9f3282fa1b..640516a2e0974 100644
--- a/llvm/docs/ReleaseNotes.md
+++ b/llvm/docs/ReleaseNotes.md
@@ -134,6 +134,8 @@ Changes to the WebAssembly Backend
Changes to the Windows Target
-----------------------------
+* `-fpseudo-probe-for-profiling` is now supported for COFF.
+
Changes to the X86 Backend
--------------------------
@@ -161,6 +163,8 @@ Changes to the Debug Info
Changes to the LLVM tools
---------------------------------
+* `llvm-profgen` now supports decoding pseudo probe for COFF binaries.
+
* `llvm-readelf` now dumps all hex format values in lower-case mode.
* Some code paths for supporting Python 2.7 in `llvm-lit` have been removed.
* Support for `%T` in lit has been removed.
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