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depends: compile FastFixedDtoa with -O1 to fix cross-arch reproducibility for arm32 #25643

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Merged
achow101 merged 1 commit into from
Jul 19, 2022
Merged

depends: compile FastFixedDtoa with -O1 to fix cross-arch reproducibility for arm32 #25643

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2 changes: 2 additions & 0 deletions depends/packages/qt.mk
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ $(package)_patches += fix_limits_header.patch
$(package)_patches += use_android_ndk23.patch
$(package)_patches += rcc_hardcode_timestamp.patch
$(package)_patches += duplicate_lcqpafonts.patch
$(package)_patches += fast_fixed_dtoa_no_optimize.patch

$(package)_qttranslations_file_name=qttranslations-$($(package)_suffix)
$(package)_qttranslations_sha256_hash=5d7869f670a135ad0986e266813b9dd5bbae2b09577338f9cdf8904d4af52db0
Expand Down Expand Up @@ -251,6 +252,7 @@ define $(package)_preprocess_cmds
patch -p1 -i $($(package)_patch_dir)/use_android_ndk23.patch && \
patch -p1 -i $($(package)_patch_dir)/rcc_hardcode_timestamp.patch && \
patch -p1 -i $($(package)_patch_dir)/duplicate_lcqpafonts.patch && \
patch -p1 -i $($(package)_patch_dir)/fast_fixed_dtoa_no_optimize.patch && \
mkdir -p qtbase/mkspecs/macx-clang-linux &&\
cp -f qtbase/mkspecs/macx-clang/qplatformdefs.h qtbase/mkspecs/macx-clang-linux/ &&\
cp -f $($(package)_patch_dir)/mac-qmake.conf qtbase/mkspecs/macx-clang-linux/qmake.conf && \
Expand Down
20 changes: 20 additions & 0 deletions depends/patches/qt/fast_fixed_dtoa_no_optimize.patch
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Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
Modify the optimisation flags for FastFixedDtoa.
This fixes a non-determinism issue in the asm produced for
this function when cross-compiling on x86_64 and aarch64 for
the arm-linux-gnueabihf HOST.

--- a/qtbase/src/3rdparty/double-conversion/fixed-dtoa.h
+++ b/qtbase/src/3rdparty/double-conversion/fixed-dtoa.h
@@ -48,9 +48,12 @@ namespace double_conversion {
//
// This method only works for some parameters. If it can't handle the input it
// returns false. The output is null-terminated when the function succeeds.
+#pragma GCC push_options
+#pragma GCC optimize ("-O1")
bool FastFixedDtoa(double v, int fractional_count,
Vector<char> buffer, int* length, int* decimal_point);

+#pragma GCC pop_options
} // namespace double_conversion

#endif // DOUBLE_CONVERSION_FIXED_DTOA_H_