Successfully identified regression in *gcc* in CI configuration tcwg_kernel/gnu-master-aarch64-lts-allyesconfig. So far, this commit has regressed CI configurations: - tcwg_kernel/gnu-master-aarch64-lts-allyesconfig

Culprit: <cut> commit a25e0b5e6ac8a77a71c229e0a7b744603365b0e9 Author: qing zhao qing.zhao@oracle.com Date: Thu Sep 9 15:44:49 2021 -0700

Add -ftrivial-auto-var-init option and uninitialized variable attribute.

Initialize automatic variables with either a pattern or with zeroes to increase the security and predictability of a program by preventing uninitialized memory disclosure and use. GCC still considers an automatic variable that doesn't have an explicit initializer as uninitialized, -Wuninitialized will still report warning messages on such automatic variables. With this option, GCC will also initialize any padding of automatic variables that have structure or union types to zeroes. You can control this behavior for a specific variable by using the variable attribute "uninitialized" to control runtime overhead.

gcc/ChangeLog:

2021-09-09 qing zhao qing.zhao@oracle.com

* builtins.c (expand_builtin_memset): Make external visible. * builtins.h (expand_builtin_memset): Declare extern. * common.opt (ftrivial-auto-var-init=): New option. * doc/extend.texi: Document the uninitialized attribute. * doc/invoke.texi: Document -ftrivial-auto-var-init. * flag-types.h (enum auto_init_type): New enumerated type auto_init_type. * gimple-fold.c (clear_padding_type): Add one new parameter. (clear_padding_union): Likewise. (clear_padding_emit_loop): Likewise. (clear_type_padding_in_mask): Likewise. (gimple_fold_builtin_clear_padding): Handle this new parameter. * gimplify.c (gimple_add_init_for_auto_var): New function. (gimple_add_padding_init_for_auto_var): New function. (is_var_need_auto_init): New function. (gimplify_decl_expr): Add initialization to automatic variables per users' requests. (gimplify_call_expr): Add one new parameter for call to __builtin_clear_padding. (gimplify_init_constructor): Add padding initialization in the end. * internal-fn.c (INIT_PATTERN_VALUE): New macro. (expand_DEFERRED_INIT): New function. * internal-fn.def (DEFERRED_INIT): New internal function. * tree-cfg.c (verify_gimple_call): Verify calls to .DEFERRED_INIT. * tree-sra.c (generate_subtree_deferred_init): New function. (scan_function): Avoid setting cannot_scalarize_away_bitmap for calls to .DEFERRED_INIT. (sra_modify_deferred_init): New function. (sra_modify_function_body): Handle calls to DEFERRED_INIT specially. * tree-ssa-structalias.c (find_func_aliases_for_call): Likewise. * tree-ssa-uninit.c (warn_uninit): Handle calls to DEFERRED_INIT specially. (check_defs): Likewise. (warn_uninitialized_vars): Likewise. * tree-ssa.c (ssa_undefined_value_p): Likewise. * tree.c (build_common_builtin_nodes): Build tree node for BUILT_IN_CLEAR_PADDING when needed.

gcc/c-family/ChangeLog:

2021-09-09 qing zhao qing.zhao@oracle.com

* c-attribs.c (handle_uninitialized_attribute): New function. (c_common_attribute_table): Add "uninitialized" attribute.

gcc/testsuite/ChangeLog:

2021-09-09 qing zhao qing.zhao@oracle.com

* c-c++-common/auto-init-1.c: New test. * c-c++-common/auto-init-10.c: New test. * c-c++-common/auto-init-11.c: New test. * c-c++-common/auto-init-12.c: New test. * c-c++-common/auto-init-13.c: New test. * c-c++-common/auto-init-14.c: New test. * c-c++-common/auto-init-15.c: New test. * c-c++-common/auto-init-16.c: New test. * c-c++-common/auto-init-2.c: New test. * c-c++-common/auto-init-3.c: New test. * c-c++-common/auto-init-4.c: New test. * c-c++-common/auto-init-5.c: New test. * c-c++-common/auto-init-6.c: New test. * c-c++-common/auto-init-7.c: New test. * c-c++-common/auto-init-8.c: New test. * c-c++-common/auto-init-9.c: New test. * c-c++-common/auto-init-esra.c: New test. * c-c++-common/auto-init-padding-1.c: New test. * c-c++-common/auto-init-padding-2.c: New test. * c-c++-common/auto-init-padding-3.c: New test. * g++.dg/auto-init-uninit-pred-1_a.C: New test. * g++.dg/auto-init-uninit-pred-2_a.C: New test. * g++.dg/auto-init-uninit-pred-3_a.C: New test. * g++.dg/auto-init-uninit-pred-4.C: New test. * gcc.dg/auto-init-sra-1.c: New test. * gcc.dg/auto-init-sra-2.c: New test. * gcc.dg/auto-init-uninit-1.c: New test. * gcc.dg/auto-init-uninit-12.c: New test. * gcc.dg/auto-init-uninit-13.c: New test. * gcc.dg/auto-init-uninit-14.c: New test. * gcc.dg/auto-init-uninit-15.c: New test. * gcc.dg/auto-init-uninit-16.c: New test. * gcc.dg/auto-init-uninit-17.c: New test. * gcc.dg/auto-init-uninit-18.c: New test. * gcc.dg/auto-init-uninit-19.c: New test. * gcc.dg/auto-init-uninit-2.c: New test. * gcc.dg/auto-init-uninit-20.c: New test. * gcc.dg/auto-init-uninit-21.c: New test. * gcc.dg/auto-init-uninit-22.c: New test. * gcc.dg/auto-init-uninit-23.c: New test. * gcc.dg/auto-init-uninit-24.c: New test. * gcc.dg/auto-init-uninit-25.c: New test. * gcc.dg/auto-init-uninit-26.c: New test. * gcc.dg/auto-init-uninit-3.c: New test. * gcc.dg/auto-init-uninit-34.c: New test. * gcc.dg/auto-init-uninit-36.c: New test. * gcc.dg/auto-init-uninit-37.c: New test. * gcc.dg/auto-init-uninit-4.c: New test. * gcc.dg/auto-init-uninit-5.c: New test. * gcc.dg/auto-init-uninit-6.c: New test. * gcc.dg/auto-init-uninit-8.c: New test. * gcc.dg/auto-init-uninit-9.c: New test. * gcc.dg/auto-init-uninit-A.c: New test. * gcc.dg/auto-init-uninit-B.c: New test. * gcc.dg/auto-init-uninit-C.c: New test. * gcc.dg/auto-init-uninit-H.c: New test. * gcc.dg/auto-init-uninit-I.c: New test. * gcc.target/aarch64/auto-init-1.c: New test. * gcc.target/aarch64/auto-init-2.c: New test. * gcc.target/aarch64/auto-init-3.c: New test. * gcc.target/aarch64/auto-init-4.c: New test. * gcc.target/aarch64/auto-init-5.c: New test. * gcc.target/aarch64/auto-init-6.c: New test. * gcc.target/aarch64/auto-init-7.c: New test. * gcc.target/aarch64/auto-init-8.c: New test. * gcc.target/aarch64/auto-init-padding-1.c: New test. * gcc.target/aarch64/auto-init-padding-10.c: New test. * gcc.target/aarch64/auto-init-padding-11.c: New test. * gcc.target/aarch64/auto-init-padding-12.c: New test. * gcc.target/aarch64/auto-init-padding-2.c: New test. * gcc.target/aarch64/auto-init-padding-3.c: New test. * gcc.target/aarch64/auto-init-padding-4.c: New test. * gcc.target/aarch64/auto-init-padding-5.c: New test. * gcc.target/aarch64/auto-init-padding-6.c: New test. * gcc.target/aarch64/auto-init-padding-7.c: New test. * gcc.target/aarch64/auto-init-padding-8.c: New test. * gcc.target/aarch64/auto-init-padding-9.c: New test. * gcc.target/i386/auto-init-1.c: New test. * gcc.target/i386/auto-init-2.c: New test. * gcc.target/i386/auto-init-21.c: New test. * gcc.target/i386/auto-init-22.c: New test. * gcc.target/i386/auto-init-23.c: New test. * gcc.target/i386/auto-init-24.c: New test. * gcc.target/i386/auto-init-3.c: New test. * gcc.target/i386/auto-init-4.c: New test. * gcc.target/i386/auto-init-5.c: New test. * gcc.target/i386/auto-init-6.c: New test. * gcc.target/i386/auto-init-7.c: New test. * gcc.target/i386/auto-init-8.c: New test. * gcc.target/i386/auto-init-padding-1.c: New test. * gcc.target/i386/auto-init-padding-10.c: New test. * gcc.target/i386/auto-init-padding-11.c: New test. * gcc.target/i386/auto-init-padding-12.c: New test. * gcc.target/i386/auto-init-padding-2.c: New test. * gcc.target/i386/auto-init-padding-3.c: New test. * gcc.target/i386/auto-init-padding-4.c: New test. * gcc.target/i386/auto-init-padding-5.c: New test. * gcc.target/i386/auto-init-padding-6.c: New test. * gcc.target/i386/auto-init-padding-7.c: New test. * gcc.target/i386/auto-init-padding-8.c: New test. * gcc.target/i386/auto-init-padding-9.c: New test. </cut>

Results regressed to (for first_bad == a25e0b5e6ac8a77a71c229e0a7b744603365b0e9) # reset_artifacts: -10 # build_abe binutils: -9 # build_abe stage1: -5 # build_abe qemu: -2 # linux_n_obj: 29 # First few build errors in logs:

from (for last_good == 5fe0865ab788bdc387b284a3ad57e5a95a767b18) # reset_artifacts: -10 # build_abe binutils: -9 # build_abe stage1: -5 # build_abe qemu: -2 # linux_n_obj: 19270 # linux build successful: all

Artifacts of last_good build: https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-master-aarch64-lts-ally... Artifacts of first_bad build: https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-master-aarch64-lts-ally... Build top page/logs: https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-master-aarch64-lts-ally...

Configuration details:

Reproduce builds: <cut> mkdir investigate-gcc-a25e0b5e6ac8a77a71c229e0a7b744603365b0e9 cd investigate-gcc-a25e0b5e6ac8a77a71c229e0a7b744603365b0e9

git clone https://git.linaro.org/toolchain/jenkins-scripts

mkdir -p artifacts/manifests curl -o artifacts/manifests/build-baseline.sh https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-master-aarch64-lts-ally... --fail curl -o artifacts/manifests/build-parameters.sh https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-master-aarch64-lts-ally... --fail curl -o artifacts/test.sh https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-master-aarch64-lts-ally... --fail chmod +x artifacts/test.sh

# Reproduce the baseline build (build all pre-requisites) ./jenkins-scripts/tcwg_kernel-build.sh @@ artifacts/manifests/build-baseline.sh

# Save baseline build state (which is then restored in artifacts/test.sh) mkdir -p ./bisect rsync -a --del --delete-excluded --exclude /bisect/ --exclude /artifacts/ --exclude /gcc/ ./ ./bisect/baseline/

cd gcc

# Reproduce first_bad build git checkout --detach a25e0b5e6ac8a77a71c229e0a7b744603365b0e9 ../artifacts/test.sh

# Reproduce last_good build git checkout --detach 5fe0865ab788bdc387b284a3ad57e5a95a767b18 ../artifacts/test.sh

cd .. </cut>

History of pending regressions and results: https://git.linaro.org/toolchain/ci/base-artifacts.git/log/?h=linaro-local/c...

Artifacts: https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-master-aarch64-lts-ally... Build log: https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-master-aarch64-lts-ally...

Full commit (up to 1000 lines): <cut> commit a25e0b5e6ac8a77a71c229e0a7b744603365b0e9 Author: qing zhao qing.zhao@oracle.com Date: Thu Sep 9 15:44:49 2021 -0700

Add -ftrivial-auto-var-init option and uninitialized variable attribute.

Initialize automatic variables with either a pattern or with zeroes to increase the security and predictability of a program by preventing uninitialized memory disclosure and use. GCC still considers an automatic variable that doesn't have an explicit initializer as uninitialized, -Wuninitialized will still report warning messages on such automatic variables. With this option, GCC will also initialize any padding of automatic variables that have structure or union types to zeroes. You can control this behavior for a specific variable by using the variable attribute "uninitialized" to control runtime overhead.

gcc/ChangeLog:

2021-09-09 qing zhao qing.zhao@oracle.com

* builtins.c (expand_builtin_memset): Make external visible. * builtins.h (expand_builtin_memset): Declare extern. * common.opt (ftrivial-auto-var-init=): New option. * doc/extend.texi: Document the uninitialized attribute. * doc/invoke.texi: Document -ftrivial-auto-var-init. * flag-types.h (enum auto_init_type): New enumerated type auto_init_type. * gimple-fold.c (clear_padding_type): Add one new parameter. (clear_padding_union): Likewise. (clear_padding_emit_loop): Likewise. (clear_type_padding_in_mask): Likewise. (gimple_fold_builtin_clear_padding): Handle this new parameter. * gimplify.c (gimple_add_init_for_auto_var): New function. (gimple_add_padding_init_for_auto_var): New function. (is_var_need_auto_init): New function. (gimplify_decl_expr): Add initialization to automatic variables per users' requests. (gimplify_call_expr): Add one new parameter for call to __builtin_clear_padding. (gimplify_init_constructor): Add padding initialization in the end. * internal-fn.c (INIT_PATTERN_VALUE): New macro. (expand_DEFERRED_INIT): New function. * internal-fn.def (DEFERRED_INIT): New internal function. * tree-cfg.c (verify_gimple_call): Verify calls to .DEFERRED_INIT. * tree-sra.c (generate_subtree_deferred_init): New function. (scan_function): Avoid setting cannot_scalarize_away_bitmap for calls to .DEFERRED_INIT. (sra_modify_deferred_init): New function. (sra_modify_function_body): Handle calls to DEFERRED_INIT specially. * tree-ssa-structalias.c (find_func_aliases_for_call): Likewise. * tree-ssa-uninit.c (warn_uninit): Handle calls to DEFERRED_INIT specially. (check_defs): Likewise. (warn_uninitialized_vars): Likewise. * tree-ssa.c (ssa_undefined_value_p): Likewise. * tree.c (build_common_builtin_nodes): Build tree node for BUILT_IN_CLEAR_PADDING when needed.

gcc/c-family/ChangeLog:

2021-09-09 qing zhao qing.zhao@oracle.com

* c-attribs.c (handle_uninitialized_attribute): New function. (c_common_attribute_table): Add "uninitialized" attribute.

gcc/testsuite/ChangeLog:

2021-09-09 qing zhao qing.zhao@oracle.com

* c-c++-common/auto-init-1.c: New test. * c-c++-common/auto-init-10.c: New test. * c-c++-common/auto-init-11.c: New test. * c-c++-common/auto-init-12.c: New test. * c-c++-common/auto-init-13.c: New test. * c-c++-common/auto-init-14.c: New test. * c-c++-common/auto-init-15.c: New test. * c-c++-common/auto-init-16.c: New test. * c-c++-common/auto-init-2.c: New test. * c-c++-common/auto-init-3.c: New test. * c-c++-common/auto-init-4.c: New test. * c-c++-common/auto-init-5.c: New test. * c-c++-common/auto-init-6.c: New test. * c-c++-common/auto-init-7.c: New test. * c-c++-common/auto-init-8.c: New test. * c-c++-common/auto-init-9.c: New test. * c-c++-common/auto-init-esra.c: New test. * c-c++-common/auto-init-padding-1.c: New test. * c-c++-common/auto-init-padding-2.c: New test. * c-c++-common/auto-init-padding-3.c: New test. * g++.dg/auto-init-uninit-pred-1_a.C: New test. * g++.dg/auto-init-uninit-pred-2_a.C: New test. * g++.dg/auto-init-uninit-pred-3_a.C: New test. * g++.dg/auto-init-uninit-pred-4.C: New test. * gcc.dg/auto-init-sra-1.c: New test. * gcc.dg/auto-init-sra-2.c: New test. * gcc.dg/auto-init-uninit-1.c: New test. * gcc.dg/auto-init-uninit-12.c: New test. * gcc.dg/auto-init-uninit-13.c: New test. * gcc.dg/auto-init-uninit-14.c: New test. * gcc.dg/auto-init-uninit-15.c: New test. * gcc.dg/auto-init-uninit-16.c: New test. * gcc.dg/auto-init-uninit-17.c: New test. * gcc.dg/auto-init-uninit-18.c: New test. * gcc.dg/auto-init-uninit-19.c: New test. * gcc.dg/auto-init-uninit-2.c: New test. * gcc.dg/auto-init-uninit-20.c: New test. * gcc.dg/auto-init-uninit-21.c: New test. * gcc.dg/auto-init-uninit-22.c: New test. * gcc.dg/auto-init-uninit-23.c: New test. * gcc.dg/auto-init-uninit-24.c: New test. * gcc.dg/auto-init-uninit-25.c: New test. * gcc.dg/auto-init-uninit-26.c: New test. * gcc.dg/auto-init-uninit-3.c: New test. * gcc.dg/auto-init-uninit-34.c: New test. * gcc.dg/auto-init-uninit-36.c: New test. * gcc.dg/auto-init-uninit-37.c: New test. * gcc.dg/auto-init-uninit-4.c: New test. * gcc.dg/auto-init-uninit-5.c: New test. * gcc.dg/auto-init-uninit-6.c: New test. * gcc.dg/auto-init-uninit-8.c: New test. * gcc.dg/auto-init-uninit-9.c: New test. * gcc.dg/auto-init-uninit-A.c: New test. * gcc.dg/auto-init-uninit-B.c: New test. * gcc.dg/auto-init-uninit-C.c: New test. * gcc.dg/auto-init-uninit-H.c: New test. * gcc.dg/auto-init-uninit-I.c: New test. * gcc.target/aarch64/auto-init-1.c: New test. * gcc.target/aarch64/auto-init-2.c: New test. * gcc.target/aarch64/auto-init-3.c: New test. * gcc.target/aarch64/auto-init-4.c: New test. * gcc.target/aarch64/auto-init-5.c: New test. * gcc.target/aarch64/auto-init-6.c: New test. * gcc.target/aarch64/auto-init-7.c: New test. * gcc.target/aarch64/auto-init-8.c: New test. * gcc.target/aarch64/auto-init-padding-1.c: New test. * gcc.target/aarch64/auto-init-padding-10.c: New test. * gcc.target/aarch64/auto-init-padding-11.c: New test. * gcc.target/aarch64/auto-init-padding-12.c: New test. * gcc.target/aarch64/auto-init-padding-2.c: New test. * gcc.target/aarch64/auto-init-padding-3.c: New test. * gcc.target/aarch64/auto-init-padding-4.c: New test. * gcc.target/aarch64/auto-init-padding-5.c: New test. * gcc.target/aarch64/auto-init-padding-6.c: New test. * gcc.target/aarch64/auto-init-padding-7.c: New test. * gcc.target/aarch64/auto-init-padding-8.c: New test. * gcc.target/aarch64/auto-init-padding-9.c: New test. * gcc.target/i386/auto-init-1.c: New test. * gcc.target/i386/auto-init-2.c: New test. * gcc.target/i386/auto-init-21.c: New test. * gcc.target/i386/auto-init-22.c: New test. * gcc.target/i386/auto-init-23.c: New test. * gcc.target/i386/auto-init-24.c: New test. * gcc.target/i386/auto-init-3.c: New test. * gcc.target/i386/auto-init-4.c: New test. * gcc.target/i386/auto-init-5.c: New test. * gcc.target/i386/auto-init-6.c: New test. * gcc.target/i386/auto-init-7.c: New test. * gcc.target/i386/auto-init-8.c: New test. * gcc.target/i386/auto-init-padding-1.c: New test. * gcc.target/i386/auto-init-padding-10.c: New test. * gcc.target/i386/auto-init-padding-11.c: New test. * gcc.target/i386/auto-init-padding-12.c: New test. * gcc.target/i386/auto-init-padding-2.c: New test. * gcc.target/i386/auto-init-padding-3.c: New test. * gcc.target/i386/auto-init-padding-4.c: New test. * gcc.target/i386/auto-init-padding-5.c: New test. * gcc.target/i386/auto-init-padding-6.c: New test. * gcc.target/i386/auto-init-padding-7.c: New test. * gcc.target/i386/auto-init-padding-8.c: New test. * gcc.target/i386/auto-init-padding-9.c: New test. --- gcc/builtins.c | 3 +- gcc/builtins.h | 1 + gcc/c-family/c-attribs.c | 27 +++ gcc/common.opt | 16 ++ gcc/doc/extend.texi | 16 ++ gcc/doc/invoke.texi | 41 +++- gcc/flag-types.h | 7 + gcc/gimple-fold.c | 54 +++-- gcc/gimplify.c | 151 ++++++++++++- gcc/internal-fn.c | 99 +++++++++ gcc/internal-fn.def | 4 + gcc/testsuite/c-c++-common/auto-init-1.c | 39 ++++ gcc/testsuite/c-c++-common/auto-init-10.c | 22 ++ gcc/testsuite/c-c++-common/auto-init-11.c | 14 ++ gcc/testsuite/c-c++-common/auto-init-12.c | 14 ++ gcc/testsuite/c-c++-common/auto-init-13.c | 23 ++ gcc/testsuite/c-c++-common/auto-init-14.c | 23 ++ gcc/testsuite/c-c++-common/auto-init-15.c | 13 ++ gcc/testsuite/c-c++-common/auto-init-16.c | 13 ++ gcc/testsuite/c-c++-common/auto-init-2.c | 39 ++++ gcc/testsuite/c-c++-common/auto-init-3.c | 19 ++ gcc/testsuite/c-c++-common/auto-init-4.c | 19 ++ gcc/testsuite/c-c++-common/auto-init-5.c | 21 ++ gcc/testsuite/c-c++-common/auto-init-6.c | 21 ++ gcc/testsuite/c-c++-common/auto-init-7.c | 35 +++ gcc/testsuite/c-c++-common/auto-init-8.c | 35 +++ gcc/testsuite/c-c++-common/auto-init-9.c | 20 ++ gcc/testsuite/c-c++-common/auto-init-esra.c | 35 +++ gcc/testsuite/c-c++-common/auto-init-padding-1.c | 23 ++ gcc/testsuite/c-c++-common/auto-init-padding-2.c | 114 ++++++++++ gcc/testsuite/c-c++-common/auto-init-padding-3.c | 114 ++++++++++ gcc/testsuite/g++.dg/auto-init-uninit-pred-1_a.C | 3 + gcc/testsuite/g++.dg/auto-init-uninit-pred-2_a.C | 3 + gcc/testsuite/g++.dg/auto-init-uninit-pred-3_a.C | 3 + gcc/testsuite/g++.dg/auto-init-uninit-pred-4.C | 3 + gcc/testsuite/gcc.dg/auto-init-sra-1.c | 24 +++ gcc/testsuite/gcc.dg/auto-init-sra-2.c | 24 +++ gcc/testsuite/gcc.dg/auto-init-uninit-1.c | 5 + gcc/testsuite/gcc.dg/auto-init-uninit-12.c | 4 + gcc/testsuite/gcc.dg/auto-init-uninit-13.c | 10 + gcc/testsuite/gcc.dg/auto-init-uninit-14.c | 4 + gcc/testsuite/gcc.dg/auto-init-uninit-15.c | 26 +++ gcc/testsuite/gcc.dg/auto-init-uninit-16.c | 25 +++ gcc/testsuite/gcc.dg/auto-init-uninit-17.c | 15 ++ gcc/testsuite/gcc.dg/auto-init-uninit-18.c | 3 + gcc/testsuite/gcc.dg/auto-init-uninit-19.c | 26 +++ gcc/testsuite/gcc.dg/auto-init-uninit-2.c | 5 + gcc/testsuite/gcc.dg/auto-init-uninit-20.c | 4 + gcc/testsuite/gcc.dg/auto-init-uninit-21.c | 4 + gcc/testsuite/gcc.dg/auto-init-uninit-22.c | 3 + gcc/testsuite/gcc.dg/auto-init-uninit-23.c | 27 +++ gcc/testsuite/gcc.dg/auto-init-uninit-24.c | 3 + gcc/testsuite/gcc.dg/auto-init-uninit-25.c | 23 ++ gcc/testsuite/gcc.dg/auto-init-uninit-26.c | 23 ++ gcc/testsuite/gcc.dg/auto-init-uninit-3.c | 5 + gcc/testsuite/gcc.dg/auto-init-uninit-34.c | 60 ++++++ gcc/testsuite/gcc.dg/auto-init-uninit-36.c | 238 +++++++++++++++++++++ gcc/testsuite/gcc.dg/auto-init-uninit-37.c | 156 ++++++++++++++ gcc/testsuite/gcc.dg/auto-init-uninit-4.c | 10 + gcc/testsuite/gcc.dg/auto-init-uninit-5.c | 6 + gcc/testsuite/gcc.dg/auto-init-uninit-6.c | 7 + gcc/testsuite/gcc.dg/auto-init-uninit-8.c | 8 + gcc/testsuite/gcc.dg/auto-init-uninit-9.c | 8 + gcc/testsuite/gcc.dg/auto-init-uninit-A.c | 7 + gcc/testsuite/gcc.dg/auto-init-uninit-B.c | 17 ++ gcc/testsuite/gcc.dg/auto-init-uninit-C.c | 5 + gcc/testsuite/gcc.dg/auto-init-uninit-H.c | 5 + gcc/testsuite/gcc.dg/auto-init-uninit-I.c | 3 + gcc/testsuite/gcc.target/aarch64/auto-init-1.c | 32 +++ gcc/testsuite/gcc.target/aarch64/auto-init-2.c | 35 +++ gcc/testsuite/gcc.target/aarch64/auto-init-3.c | 19 ++ gcc/testsuite/gcc.target/aarch64/auto-init-4.c | 19 ++ gcc/testsuite/gcc.target/aarch64/auto-init-5.c | 19 ++ gcc/testsuite/gcc.target/aarch64/auto-init-6.c | 18 ++ gcc/testsuite/gcc.target/aarch64/auto-init-7.c | 32 +++ gcc/testsuite/gcc.target/aarch64/auto-init-8.c | 32 +++ .../gcc.target/aarch64/auto-init-padding-1.c | 17 ++ .../gcc.target/aarch64/auto-init-padding-10.c | 22 ++ .../gcc.target/aarch64/auto-init-padding-11.c | 27 +++ .../gcc.target/aarch64/auto-init-padding-12.c | 27 +++ .../gcc.target/aarch64/auto-init-padding-2.c | 18 ++ .../gcc.target/aarch64/auto-init-padding-3.c | 27 +++ .../gcc.target/aarch64/auto-init-padding-4.c | 27 +++ .../gcc.target/aarch64/auto-init-padding-5.c | 22 ++ .../gcc.target/aarch64/auto-init-padding-6.c | 20 ++ .../gcc.target/aarch64/auto-init-padding-7.c | 20 ++ .../gcc.target/aarch64/auto-init-padding-8.c | 22 ++ .../gcc.target/aarch64/auto-init-padding-9.c | 21 ++ gcc/testsuite/gcc.target/i386/auto-init-1.c | 32 +++ gcc/testsuite/gcc.target/i386/auto-init-2.c | 36 ++++ gcc/testsuite/gcc.target/i386/auto-init-21.c | 14 ++ gcc/testsuite/gcc.target/i386/auto-init-22.c | 14 ++ gcc/testsuite/gcc.target/i386/auto-init-23.c | 13 ++ gcc/testsuite/gcc.target/i386/auto-init-24.c | 13 ++ gcc/testsuite/gcc.target/i386/auto-init-3.c | 17 ++ gcc/testsuite/gcc.target/i386/auto-init-4.c | 20 ++ gcc/testsuite/gcc.target/i386/auto-init-5.c | 20 ++ gcc/testsuite/gcc.target/i386/auto-init-6.c | 19 ++ gcc/testsuite/gcc.target/i386/auto-init-7.c | 33 +++ gcc/testsuite/gcc.target/i386/auto-init-8.c | 35 +++ .../gcc.target/i386/auto-init-padding-1.c | 19 ++ .../gcc.target/i386/auto-init-padding-10.c | 21 ++ .../gcc.target/i386/auto-init-padding-11.c | 26 +++ .../gcc.target/i386/auto-init-padding-12.c | 26 +++ .../gcc.target/i386/auto-init-padding-2.c | 19 ++ .../gcc.target/i386/auto-init-padding-3.c | 30 +++ .../gcc.target/i386/auto-init-padding-4.c | 28 +++ .../gcc.target/i386/auto-init-padding-5.c | 21 ++ .../gcc.target/i386/auto-init-padding-6.c | 22 ++ .../gcc.target/i386/auto-init-padding-7.c | 22 ++ .../gcc.target/i386/auto-init-padding-8.c | 22 ++ .../gcc.target/i386/auto-init-padding-9.c | 22 ++ gcc/tree-cfg.c | 47 +++- gcc/tree-sra.c | 124 ++++++++++- gcc/tree-ssa-structalias.c | 3 + gcc/tree-ssa-uninit.c | 48 +++++ gcc/tree-ssa.c | 40 ++++ gcc/tree.c | 13 ++ 118 files changed, 3131 insertions(+), 44 deletions(-)

diff --git a/gcc/builtins.c b/gcc/builtins.c index 99548627761..3e57eb03af0 100644 --- a/gcc/builtins.c +++ b/gcc/builtins.c @@ -142,7 +142,6 @@ static rtx expand_builtin_strcpy (tree, rtx); static rtx expand_builtin_strcpy_args (tree, tree, tree, rtx); static rtx expand_builtin_stpcpy (tree, rtx, machine_mode); static rtx expand_builtin_strncpy (tree, rtx); -static rtx expand_builtin_memset (tree, rtx, machine_mode); static rtx expand_builtin_memset_args (tree, tree, tree, rtx, machine_mode, tree); static rtx expand_builtin_bzero (tree); static rtx expand_builtin_strlen (tree, rtx, machine_mode); @@ -3872,7 +3871,7 @@ builtin_memset_gen_str (void *data, void *prev, try to get the result in TARGET, if convenient (and in mode MODE if that's convenient). */

-static rtx +rtx expand_builtin_memset (tree exp, rtx target, machine_mode mode) { if (!validate_arglist (exp, diff --git a/gcc/builtins.h b/gcc/builtins.h index 16b47ac1a7b..d330b78e591 100644 --- a/gcc/builtins.h +++ b/gcc/builtins.h @@ -114,6 +114,7 @@ extern rtx builtin_strncpy_read_str (void *, void *, HOST_WIDE_INT, fixed_size_mode); extern rtx builtin_memset_read_str (void *, void *, HOST_WIDE_INT, fixed_size_mode); +extern rtx expand_builtin_memset (tree, rtx, machine_mode); extern rtx expand_builtin_saveregs (void); extern tree std_build_builtin_va_list (void); extern tree std_fn_abi_va_list (tree); diff --git a/gcc/c-family/c-attribs.c b/gcc/c-family/c-attribs.c index d14e9c441b3..007b928c54b 100644 --- a/gcc/c-family/c-attribs.c +++ b/gcc/c-family/c-attribs.c @@ -83,6 +83,7 @@ static tree handle_artificial_attribute (tree *, tree, tree, int, bool *); static tree handle_flatten_attribute (tree *, tree, tree, int, bool *); static tree handle_error_attribute (tree *, tree, tree, int, bool *); static tree handle_used_attribute (tree *, tree, tree, int, bool *); +static tree handle_uninitialized_attribute (tree *, tree, tree, int, bool *); static tree handle_externally_visible_attribute (tree *, tree, tree, int, bool *); static tree handle_no_reorder_attribute (tree *, tree, tree, int, @@ -333,6 +334,8 @@ const struct attribute_spec c_common_attribute_table[] = handle_used_attribute, NULL }, { "unused", 0, 0, false, false, false, false, handle_unused_attribute, NULL }, + { "uninitialized", 0, 0, true, false, false, false, + handle_uninitialized_attribute, NULL }, { "retain", 0, 0, true, false, false, false, handle_retain_attribute, NULL }, { "externally_visible", 0, 0, true, false, false, false, @@ -1617,6 +1620,30 @@ handle_retain_attribute (tree *pnode, tree name, tree ARG_UNUSED (args), return NULL_TREE; }

+/* Handle an "uninitialized" attribute; arguments as in + struct attribute_spec.handler. */ + +static tree +handle_uninitialized_attribute (tree *node, tree name, tree ARG_UNUSED (args), + int ARG_UNUSED (flags), bool *no_add_attrs) +{ + tree decl = *node; + if (!VAR_P (decl)) + { + warning (OPT_Wattributes, "%qE attribute ignored because %qD " + "is not a variable", name, decl); + *no_add_attrs = true; + } + else if (TREE_STATIC (decl) || DECL_EXTERNAL (decl)) + { + warning (OPT_Wattributes, "%qE attribute ignored because %qD " + "is not a local variable", name, decl); + *no_add_attrs = true; + } + + return NULL_TREE; +} + /* Handle a "externally_visible" attribute; arguments as in struct attribute_spec.handler. */

diff --git a/gcc/common.opt b/gcc/common.opt index f103a7de004..b921f5e3b25 100644 --- a/gcc/common.opt +++ b/gcc/common.opt @@ -3081,6 +3081,22 @@ ftree-scev-cprop Common Var(flag_tree_scev_cprop) Init(1) Optimization Enable copy propagation of scalar-evolution information.

+ftrivial-auto-var-init= +Common Joined RejectNegative Enum(auto_init_type) Var(flag_auto_var_init) Init(AUTO_INIT_UNINITIALIZED) Optimization +-ftrivial-auto-var-init=[uninitialized|pattern|zero] Add initializations to automatic variables. + +Enum +Name(auto_init_type) Type(enum auto_init_type) UnknownError(unrecognized automatic variable initialization type %qs) + +EnumValue +Enum(auto_init_type) String(uninitialized) Value(AUTO_INIT_UNINITIALIZED) + +EnumValue +Enum(auto_init_type) String(pattern) Value(AUTO_INIT_PATTERN) + +EnumValue +Enum(auto_init_type) String(zero) Value(AUTO_INIT_ZERO) + ; -fverbose-asm causes extra commentary information to be produced in ; the generated assembly code (to make it more readable). This option ; is generally only of use to those who actually need to read the diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index 52bc4e5b76e..8b324a097a4 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -7610,6 +7610,22 @@ will be placed in new, unique sections.

This additional functionality requires Binutils version 2.36 or later.

+@item uninitialized +@cindex @code{uninitialized} variable attribute +This attribute, attached to a variable with automatic storage, means that +the variable should not be automatically initialized by the compiler when +the option @code{-ftrivial-auto-var-init} presents. + +With the option @code{-ftrivial-auto-var-init}, all the automatic variables +that do not have explicit initializers will be initialized by the compiler. +These additional compiler initializations might incur run-time overhead, +sometimes dramatically. This attribute can be used to mark some variables +to be excluded from such automatical initialization in order to reduce runtime +overhead. + +This attribute has no effect when the option @code{-ftrivial-auto-var-init} +does not present. + @item vector_size (@var{bytes}) @cindex @code{vector_size} variable attribute This attribute specifies the vector size for the type of the declared diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index d4b3a66ee4f..b08a5eb4d73 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -573,9 +573,9 @@ Objective-C and Objective-C++ Dialects}. -ftree-parallelize-loops=@var{n} -ftree-pre -ftree-partial-pre -ftree-pta @gol -ftree-reassoc -ftree-scev-cprop -ftree-sink -ftree-slsr -ftree-sra @gol -ftree-switch-conversion -ftree-tail-merge @gol --ftree-ter -ftree-vectorize -ftree-vrp -funconstrained-commons @gol --funit-at-a-time -funroll-all-loops -funroll-loops @gol --funsafe-math-optimizations -funswitch-loops @gol +-ftree-ter -ftree-vectorize -ftree-vrp -ftrivial-auto-var-init @gol +-funconstrained-commons -funit-at-a-time -funroll-all-loops @gol +-funroll-loops -funsafe-math-optimizations -funswitch-loops @gol -fipa-ra -fvariable-expansion-in-unroller -fvect-cost-model -fvpt @gol -fweb -fwhole-program -fwpa -fuse-linker-plugin -fzero-call-used-regs @gol --param @var{name}=@var{value} @@ -11843,6 +11843,41 @@ Perform basic block vectorization on trees. This flag is enabled by default at @option{-O3} and by @option{-ftree-vectorize}, @option{-fprofile-use}, and @option{-fauto-profile}.

+@item -ftrivial-auto-var-init=@var{choice} +@opindex ftrivial-auto-var-init +Initialize automatic variables with either a pattern or with zeroes to increase +the security and predictability of a program by preventing uninitialized memory +disclosure and use. +GCC still considers an automatic variable that doesn't have an explicit +initializer as uninitialized, -Wuninitialized will still report warning messages +on such automatic variables. +With this option, GCC will also initialize any padding of automatic variables +that have structure or union types to zeroes. + +The three values of @var{choice} are: + +@itemize @bullet +@item +@samp{uninitialized} doesn't initialize any automatic variables. +This is C and C++'s default. + +@item +@samp{pattern} Initialize automatic variables with values which will likely +transform logic bugs into crashes down the line, are easily recognized in a +crash dump and without being values that programmers can rely on for useful +program semantics. +The current value is byte-repeatable pattern with byte "0xFE". +The values used for pattern initialization might be changed in the future. + +@item +@samp{zero} Initialize automatic variables with zeroes. +@end itemize + +The default is @samp{uninitialized}. + +You can control this behavior for a specific variable by using the variable +attribute @code{uninitialized} (@pxref{Variable Attributes}). + @item -fvect-cost-model=@var{model} @opindex fvect-cost-model Alter the cost model used for vectorization. The @var{model} argument diff --git a/gcc/flag-types.h b/gcc/flag-types.h index 45a2338d5f6..5bd1f771c8b 100644 --- a/gcc/flag-types.h +++ b/gcc/flag-types.h @@ -281,6 +281,13 @@ enum vect_cost_model { VECT_COST_MODEL_DEFAULT = 1 };

+/* Automatic variable initialization type. */ +enum auto_init_type { + AUTO_INIT_UNINITIALIZED = 0, + AUTO_INIT_PATTERN = 1, + AUTO_INIT_ZERO = 2 +}; + /* Different instrumentation modes. */ enum sanitize_code { /* AddressSanitizer. */ diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c index 3f2c176cff6..dd0e6b5daff 100644 --- a/gcc/gimple-fold.c +++ b/gcc/gimple-fold.c @@ -4518,12 +4518,14 @@ clear_padding_add_padding (clear_padding_struct *buf, } }

-static void clear_padding_type (clear_padding_struct *, tree, HOST_WIDE_INT); +static void clear_padding_type (clear_padding_struct *, tree, + HOST_WIDE_INT, bool);

/* Clear padding bits of union type TYPE. */

static void -clear_padding_union (clear_padding_struct *buf, tree type, HOST_WIDE_INT sz) +clear_padding_union (clear_padding_struct *buf, tree type, + HOST_WIDE_INT sz, bool for_auto_init) { clear_padding_struct *union_buf; HOST_WIDE_INT start_off = 0, next_off = 0; @@ -4568,7 +4570,7 @@ clear_padding_union (clear_padding_struct *buf, tree type, HOST_WIDE_INT sz) continue; gcc_assert (TREE_CODE (TREE_TYPE (field)) == ARRAY_TYPE && !COMPLETE_TYPE_P (TREE_TYPE (field))); - if (!buf->clear_in_mask) + if (!buf->clear_in_mask && !for_auto_init) error_at (buf->loc, "flexible array member %qD does not have " "well defined padding bits for %qs", field, "__builtin_clear_padding"); @@ -4579,7 +4581,7 @@ clear_padding_union (clear_padding_struct *buf, tree type, HOST_WIDE_INT sz) union_buf->off = start_off; union_buf->size = start_size; memset (union_buf->buf, ~0, start_size); - clear_padding_type (union_buf, TREE_TYPE (field), fldsz); + clear_padding_type (union_buf, TREE_TYPE (field), fldsz, for_auto_init); clear_padding_add_padding (union_buf, sz - fldsz); clear_padding_flush (union_buf, true); } @@ -4649,7 +4651,8 @@ clear_padding_type_may_have_padding_p (tree type) __builtin_clear_padding (buf.base); */

static void -clear_padding_emit_loop (clear_padding_struct *buf, tree type, tree end) +clear_padding_emit_loop (clear_padding_struct *buf, tree type, + tree end, bool for_auto_init) { tree l1 = create_artificial_label (buf->loc); tree l2 = create_artificial_label (buf->loc); @@ -4660,7 +4663,7 @@ clear_padding_emit_loop (clear_padding_struct *buf, tree type, tree end) g = gimple_build_label (l1); gimple_set_location (g, buf->loc); gsi_insert_before (buf->gsi, g, GSI_SAME_STMT); - clear_padding_type (buf, type, buf->sz); + clear_padding_type (buf, type, buf->sz, for_auto_init); clear_padding_flush (buf, true); g = gimple_build_assign (buf->base, POINTER_PLUS_EXPR, buf->base, size_int (buf->sz)); @@ -4678,10 +4681,16 @@ clear_padding_emit_loop (clear_padding_struct *buf, tree type, tree end) }

/* Clear padding bits for TYPE. Called recursively from - gimple_fold_builtin_clear_padding. */ + gimple_fold_builtin_clear_padding. If FOR_AUTO_INIT is true, + the __builtin_clear_padding is not called by the end user, + instead, it's inserted by the compiler to initialize the + paddings of automatic variable. Therefore, we should not + emit the error messages for flexible array members to confuse + the end user. */

static void -clear_padding_type (clear_padding_struct *buf, tree type, HOST_WIDE_INT sz) +clear_padding_type (clear_padding_struct *buf, tree type, + HOST_WIDE_INT sz, bool for_auto_init) { switch (TREE_CODE (type)) { @@ -4765,7 +4774,7 @@ clear_padding_type (clear_padding_struct *buf, tree type, HOST_WIDE_INT sz) continue; gcc_assert (TREE_CODE (ftype) == ARRAY_TYPE && !COMPLETE_TYPE_P (ftype)); - if (!buf->clear_in_mask) + if (!buf->clear_in_mask && !for_auto_init) error_at (buf->loc, "flexible array member %qD does not " "have well defined padding bits for %qs", field, "__builtin_clear_padding"); @@ -4781,7 +4790,8 @@ clear_padding_type (clear_padding_struct *buf, tree type, HOST_WIDE_INT sz) gcc_assert (pos >= 0 && fldsz >= 0 && pos >= cur_pos); clear_padding_add_padding (buf, pos - cur_pos); cur_pos = pos; - clear_padding_type (buf, TREE_TYPE (field), fldsz); + clear_padding_type (buf, TREE_TYPE (field), + fldsz, for_auto_init); cur_pos += fldsz; } } @@ -4821,7 +4831,7 @@ clear_padding_type (clear_padding_struct *buf, tree type, HOST_WIDE_INT sz) buf->align = TYPE_ALIGN (elttype); buf->off = 0; buf->size = 0; - clear_padding_emit_loop (buf, elttype, end); + clear_padding_emit_loop (buf, elttype, end, for_auto_init); buf->base = base; buf->sz = prev_sz; buf->align = prev_align; @@ -4831,10 +4841,10 @@ clear_padding_type (clear_padding_struct *buf, tree type, HOST_WIDE_INT sz) break; } for (HOST_WIDE_INT i = 0; i < nelts; i++) - clear_padding_type (buf, TREE_TYPE (type), fldsz); + clear_padding_type (buf, TREE_TYPE (type), fldsz, for_auto_init); break; case UNION_TYPE: - clear_padding_union (buf, type, sz); + clear_padding_union (buf, type, sz, for_auto_init); break; case REAL_TYPE: gcc_assert ((size_t) sz <= clear_padding_unit); @@ -4858,14 +4868,14 @@ clear_padding_type (clear_padding_struct *buf, tree type, HOST_WIDE_INT sz) break; case COMPLEX_TYPE: fldsz = int_size_in_bytes (TREE_TYPE (type)); - clear_padding_type (buf, TREE_TYPE (type), fldsz); - clear_padding_type (buf, TREE_TYPE (type), fldsz); + clear_padding_type (buf, TREE_TYPE (type), fldsz, for_auto_init); + clear_padding_type (buf, TREE_TYPE (type), fldsz, for_auto_init); break; case VECTOR_TYPE: nelts = TYPE_VECTOR_SUBPARTS (type).to_constant (); fldsz = int_size_in_bytes (TREE_TYPE (type)); for (HOST_WIDE_INT i = 0; i < nelts; i++) - clear_padding_type (buf, TREE_TYPE (type), fldsz); + clear_padding_type (buf, TREE_TYPE (type), fldsz, for_auto_init); break; case NULLPTR_TYPE: gcc_assert ((size_t) sz <= clear_padding_unit); @@ -4901,7 +4911,7 @@ clear_type_padding_in_mask (tree type, unsigned char *mask) buf.sz = int_size_in_bytes (type); buf.size = 0; buf.union_ptr = mask; - clear_padding_type (&buf, type, buf.sz); + clear_padding_type (&buf, type, buf.sz, false); clear_padding_flush (&buf, true); }

@@ -4911,9 +4921,13 @@ static bool gimple_fold_builtin_clear_padding (gimple_stmt_iterator *gsi) { gimple *stmt = gsi_stmt (*gsi); - gcc_assert (gimple_call_num_args (stmt) == 2); + gcc_assert (gimple_call_num_args (stmt) == 3); tree ptr = gimple_call_arg (stmt, 0); tree typearg = gimple_call_arg (stmt, 1); + /* the 3rd argument of __builtin_clear_padding is to distinguish whether + this call is made by the user or by the compiler for automatic variable + initialization. */ + bool for_auto_init = (bool) TREE_INT_CST_LOW (gimple_call_arg (stmt, 2)); tree type = TREE_TYPE (TREE_TYPE (typearg)); location_t loc = gimple_location (stmt); clear_padding_struct buf; @@ -4970,7 +4984,7 @@ gimple_fold_builtin_clear_padding (gimple_stmt_iterator *gsi) buf.sz = eltsz; buf.align = TYPE_ALIGN (elttype); buf.alias_type = build_pointer_type (elttype); - clear_padding_emit_loop (&buf, elttype, end); + clear_padding_emit_loop (&buf, elttype, end, for_auto_init); } } else @@ -4983,7 +4997,7 @@ gimple_fold_builtin_clear_padding (gimple_stmt_iterator *gsi) gsi_insert_before (gsi, g, GSI_SAME_STMT); } buf.alias_type = build_pointer_type (type); - clear_padding_type (&buf, type, buf.sz); + clear_padding_type (&buf, type, buf.sz, for_auto_init); clear_padding_flush (&buf, true); }

diff --git a/gcc/gimplify.c b/gcc/gimplify.c index 99d1c7fcce4..3314f76cf3f 100644 --- a/gcc/gimplify.c +++ b/gcc/gimplify.c @@ -1743,6 +1743,94 @@ force_labels_r (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED) return NULL_TREE; }

+/* Generate an initialization to automatic variable DECL based on INIT_TYPE. + Build a call to internal const function DEFERRED_INIT: + 1st argument: SIZE of the DECL; + 2nd argument: INIT_TYPE; + 3rd argument: IS_VLA, 0 NO, 1 YES; + + as LHS = DEFERRED_INIT (SIZE of the DECL, INIT_TYPE, IS_VLA) + if IS_VLA is false, the LHS is the DECL itself, + if IS_VLA is true, the LHS is a MEM_REF whose address is the pointer + to this DECL. */ +static void +gimple_add_init_for_auto_var (tree decl, + enum auto_init_type init_type, + bool is_vla, + gimple_seq *seq_p) +{ + gcc_assert (auto_var_p (decl)); + gcc_assert (init_type > AUTO_INIT_UNINITIALIZED); + location_t loc = EXPR_LOCATION (decl); + tree decl_size = TYPE_SIZE_UNIT (TREE_TYPE (decl)); + + tree init_type_node + = build_int_cst (integer_type_node, (int) init_type); + tree is_vla_node + = build_int_cst (integer_type_node, (int) is_vla); + + tree call = build_call_expr_internal_loc (loc, IFN_DEFERRED_INIT, + TREE_TYPE (decl), 3, + decl_size, init_type_node, + is_vla_node); + + gimplify_assign (decl, call, seq_p); +} + +/* Generate padding initialization for automatic vairable DECL. + C guarantees that brace-init with fewer initializers than members + aggregate will initialize the rest of the aggregate as-if it were + static initialization. In turn static initialization guarantees + that padding is initialized to zero. So, we always initialize paddings + to zeroes regardless INIT_TYPE. + To do the padding initialization, we insert a call to + __BUILTIN_CLEAR_PADDING (&decl, 0, for_auto_init = true). + Note, we add an additional dummy argument for __BUILTIN_CLEAR_PADDING, + 'for_auto_init' to distinguish whether this call is for automatic + variable initialization or not. + */ +static void +gimple_add_padding_init_for_auto_var (tree decl, bool is_vla, + gimple_seq *seq_p) +{ + tree addr_of_decl = NULL_TREE; + bool for_auto_init = true; + tree fn = builtin_decl_explicit (BUILT_IN_CLEAR_PADDING); + + if (is_vla) + { + /* The temporary address variable for this vla should be + created in gimplify_vla_decl. */ + gcc_assert (DECL_HAS_VALUE_EXPR_P (decl)); + gcc_assert (TREE_CODE (DECL_VALUE_EXPR (decl)) == INDIRECT_REF); + addr_of_decl = TREE_OPERAND (DECL_VALUE_EXPR (decl), 0); + } + else + { + mark_addressable (decl); + addr_of_decl = build_fold_addr_expr (decl); + } + + gimple *call = gimple_build_call (fn, + 3, addr_of_decl, + build_zero_cst (TREE_TYPE (addr_of_decl)), + build_int_cst (integer_type_node, + (int) for_auto_init)); + gimplify_seq_add_stmt (seq_p, call); +} + +/* Return true if the DECL need to be automaticly initialized by the + compiler. */ +static bool +is_var_need_auto_init (tree decl) +{ + if (auto_var_p (decl) + && (flag_auto_var_init > AUTO_INIT_UNINITIALIZED) + && (!lookup_attribute ("uninitialized", DECL_ATTRIBUTES (decl)))) + return true; + return false; +} + /* Gimplify a DECL_EXPR node *STMT_P by making any necessary allocation and initialization explicit. */

@@ -1840,6 +1928,26 @@ gimplify_decl_expr (tree *stmt_p, gimple_seq *seq_p) as they may contain a label address. */ walk_tree (&init, force_labels_r, NULL, NULL); } + /* When there is no explicit initializer, if the user requested, + We should insert an artifical initializer for this automatic + variable. */ + else if (is_var_need_auto_init (decl)) + { + gimple_add_init_for_auto_var (decl, + flag_auto_var_init, + is_vla, + seq_p); + /* The expanding of a call to the above .DEFERRED_INIT will apply + block initialization to the whole space covered by this variable. + As a result, all the paddings will be initialized to zeroes + for zero initialization and 0xFE byte-repeatable patterns for + pattern initialization. + In order to make the paddings as zeroes for pattern init, We + should add a call to __builtin_clear_padding to clear the + paddings to zero in compatiple with CLANG. */ + if (flag_auto_var_init == AUTO_INIT_PATTERN) + gimple_add_padding_init_for_auto_var (decl, is_vla, seq_p); + } }

return GS_ALL_DONE; @@ -3411,11 +3519,15 @@ gimplify_call_expr (tree *expr_p, gimple_seq *pre_p, bool want_value) { /* Remember the original type of the argument in an internal dummy second argument, as in GIMPLE pointer conversions are - useless. */ + useless. also mark this call as not for automatic initialization + in the internal dummy third argument. */ p = CALL_EXPR_ARG (*expr_p, 0); + bool for_auto_init = false; *expr_p - = build_call_expr_loc (EXPR_LOCATION (*expr_p), fndecl, 2, p, - build_zero_cst (TREE_TYPE (p))); + = build_call_expr_loc (EXPR_LOCATION (*expr_p), fndecl, 3, p, + build_zero_cst (TREE_TYPE (p)), + build_int_cst (integer_type_node, + (int) for_auto_init)); return GS_OK; } break; @@ -4872,6 +4984,9 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p, tree object, ctor, type; enum gimplify_status ret; vec<constructor_elt, va_gc> *elts; + bool cleared = false; + bool is_empty_ctor = false; + bool is_init_expr = (TREE_CODE (*expr_p) == INIT_EXPR);

gcc_assert (TREE_CODE (TREE_OPERAND (*expr_p, 1)) == CONSTRUCTOR);

@@ -4914,7 +5029,7 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p, struct gimplify_init_ctor_preeval_data preeval_data; HOST_WIDE_INT num_ctor_elements, num_nonzero_elements; HOST_WIDE_INT num_unique_nonzero_elements; - bool cleared, complete_p, valid_const_initializer; + bool complete_p, valid_const_initializer;

/* Aggregate types must lower constructors to initialization of individual elements. The exception is that a CONSTRUCTOR node @@ -4923,6 +5038,7 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p, { if (notify_temp_creation) return GS_OK; + is_empty_ctor = true; break; }

@@ -5248,13 +5364,28 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p, if (want_value) { *expr_p = object; - return GS_OK; + ret = GS_OK; } else { *expr_p = NULL; - return GS_ALL_DONE; - } + ret = GS_ALL_DONE; + } + + /* If the user requests to initialize automatic variables, we + should initialize paddings inside the variable. Add a call to + __BUILTIN_CLEAR_PADDING (&object, 0, for_auto_init = true) to + initialize paddings of object always to zero regardless of + INIT_TYPE. Note, we will not insert this call if the aggregate + variable has be completely cleared already or it's initialized + with an empty constructor. */ + if (is_init_expr + && ((AGGREGATE_TYPE_P (type) && !cleared && !is_empty_ctor) + || !AGGREGATE_TYPE_P (type)) + && is_var_need_auto_init (object)) + gimple_add_padding_init_for_auto_var (object, false, pre_p); + + return ret; }

/* Given a pointer value OP0, return a simplified version of an @@ -5395,10 +5526,12 @@ gimplify_modify_expr_rhs (tree *expr_p, tree *from_p, tree *to_p, crack at this before we break it down. */ if (ret != GS_UNHANDLED) break; + /* If we're initializing from a CONSTRUCTOR, break this into individual MODIFY_EXPRs. */ - return gimplify_init_constructor (expr_p, pre_p, post_p, want_value, - false); + ret = gimplify_init_constructor (expr_p, pre_p, post_p, want_value, + false); + return ret;

case COND_EXPR: /* If we're assigning to a non-register type, push the assignment diff --git a/gcc/internal-fn.c b/gcc/internal-fn.c index 1360a00f0b9..ada2a820ff1 100644 --- a/gcc/internal-fn.c +++ b/gcc/internal-fn.c @@ -53,6 +53,9 @@ along with GCC; see the file COPYING3. If not see #include "rtl-iter.h" #include "gimple-range.h"

+/* For lang_hooks.types.type_for_mode. */ +#include "langhooks.h" + /* The names of each internal function, indexed by function number. */ const char *const internal_fn_name_array[] = { #define DEF_INTERNAL_FN(CODE, FLAGS, FNSPEC) #CODE, @@ -2977,6 +2980,102 @@ expand_UNIQUE (internal_fn, gcall *stmt) emit_insn (pattern); }

+/* Expand the IFN_DEFERRED_INIT function: + LHS = DEFERRED_INIT (SIZE of the DECL, INIT_TYPE, IS_VLA); + + if IS_VLA is false, the LHS is the DECL itself, + if IS_VLA is true, the LHS is a MEM_REF whose address is the pointer + to this DECL. + + Initialize the LHS with zero/pattern according to its second argument + INIT_TYPE: + if INIT_TYPE is AUTO_INIT_ZERO, use zeroes to initialize; + if INIT_TYPE is AUTO_INIT_PATTERN, use 0xFE byte-repeatable pattern + to initialize; + The LHS variable is initialized including paddings. + The reasons to choose 0xFE for pattern initialization are: + 1. It is a non-canonical virtual address on x86_64, and at the + high end of the i386 kernel address space. + 2. It is a very large float value (-1.694739530317379e+38). + 3. It is also an unusual number for integers. */ +#define INIT_PATTERN_VALUE 0xFE +static void +expand_DEFERRED_INIT (internal_fn, gcall *stmt) +{ + tree lhs = gimple_call_lhs (stmt); + tree var_size = gimple_call_arg (stmt, 0); + enum auto_init_type init_type + = (enum auto_init_type) TREE_INT_CST_LOW (gimple_call_arg (stmt, 1)); + bool is_vla = (bool) TREE_INT_CST_LOW (gimple_call_arg (stmt, 2)); + bool reg_lhs = true; + + tree var_type = TREE_TYPE (lhs); + gcc_assert (init_type > AUTO_INIT_UNINITIALIZED); + + if (DECL_P (lhs)) + { + rtx tem = expand_expr (lhs, NULL_RTX, VOIDmode, EXPAND_WRITE); + reg_lhs = !MEM_P (tem); + } + else if (TREE_CODE (lhs) == SSA_NAME) + reg_lhs = true; + else + { + gcc_assert (is_vla); + reg_lhs = false; + } + + + if (!reg_lhs) + { + /* If this is a VLA or the variable is not in register, + expand to a memset to initialize it. */ + + mark_addressable (lhs); + tree var_addr = build_fold_addr_expr (lhs); + + tree value = (init_type == AUTO_INIT_PATTERN) ? + build_int_cst (integer_type_node, + INIT_PATTERN_VALUE) : + integer_zero_node; + tree m_call = build_call_expr (builtin_decl_implicit (BUILT_IN_MEMSET), + 3, var_addr, value, var_size); + /* Expand this memset call. */ + expand_builtin_memset (m_call, NULL_RTX, TYPE_MODE (var_type)); + } + else + { + /* If this variable is in a register, use expand_assignment might + generate better code. */ + tree init = build_zero_cst (var_type); + unsigned HOST_WIDE_INT total_bytes + = tree_to_uhwi (TYPE_SIZE_UNIT (var_type)); + + if (init_type == AUTO_INIT_PATTERN) + { + tree alt_type = NULL_TREE; + if (!can_native_interpret_type_p (var_type)) + { + alt_type </cut>