Basic block sections should enable not function sections implicitly.

Basic block sections enables function sections implicitly, this is not needed
and is inefficient with "=list" option.

We had bas

Basic block sections should enable not function sections implicitly.

Basic block sections enables function sections implicitly, this is not needed
and is inefficient with "=list" option.

We had basic block sections enable function sections implicitly in clang. This
is particularly inefficient with "=list" option as it places functions that do
not have any basic block sections in separate sections. This causes unnecessary
object file overhead for large applications.

This patch disables this implicit behavior. It only creates function sections
for those functions that require basic block sections.

This patch is the second of two patches and this patch removes the implicit
enabling of function sections with basic block sections in clang.

Differential Revision: https://reviews.llvm.org/D93876

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[test] Use host platform specific error message substitution in lit tests

On z/OS, the following error message is not matched correctly in lit tests.

```
EDC5129I No such file or directory.
```

Th

[test] Use host platform specific error message substitution in lit tests

On z/OS, the following error message is not matched correctly in lit tests.

```
EDC5129I No such file or directory.
```

This patch uses a lit config substitution to check for platform specific error messages.

Reviewed By: muiez, jhenderson

Differential Revision: https://reviews.llvm.org/D95246

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Revert "[SystemZ][z/OS] Fix No such file or directory expression error"

This reverts commit 06f8a49693957bc27b83e0ab5f429ff874941a07.

[SystemZ][z/OS] Fix No such file or directory expression error matching in lit tests

On z/OS, the following error message is not matched correctly in lit tests. This patch updates the CHECK expressi

[SystemZ][z/OS] Fix No such file or directory expression error matching in lit tests

On z/OS, the following error message is not matched correctly in lit tests. This patch updates the CHECK expression to match successfully.
```
EDC5129I No such file or directory.
```

Reviewed By: muiez

Differential Revision: https://reviews.llvm.org/D94239

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Append ".__part." to every basic block section symbol.

Every basic block section symbol created by -fbasic-block-sections will contain
".__part." to know that this symbol corresponds to a basic bloc

Append ".__part." to every basic block section symbol.

Every basic block section symbol created by -fbasic-block-sections will contain
".__part." to know that this symbol corresponds to a basic block fragment of
the function.

This patch solves two problems:

a) Like D89617, we want function symbols with suffixes to be properly qualified
so that external tools like profile aggregators know exactly what this
symbol corresponds to.
b) The current basic block naming just adds a ".N" to the symbol name where N is
some integer. This collides with how clang creates __cxx_global_var_init.N.
clang creates these symbol names to call constructor functions and basic
block symbol naming should not use the same style.

Fixed all the test cases and added an extra test for __cxx_global_var_init
breakage.

Differential Revision: https://reviews.llvm.org/D93082

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-fbasic-block-sections=list=: Suppress output if failed to open the file

Reviewed By: tmsriram

Differential Revision: https://reviews.llvm.org/D90815

Simple fix to basic-block-sections to replace emit-obj with emit-llvm

emit-obj is unnecessary here and further wasn't redirected to /dev/null.

[clang testing] Fix a read-only source build system failure

[test] Fix -fbasic-block-sections= test on Windows after D89500

Improve file doesnt exist error with -fbasic-block-sections=

With -fbasicblock-sections=, let the front-end handle the case where the file
doesnt exist. The driver only checks if the option syntax i

Improve file doesnt exist error with -fbasic-block-sections=

With -fbasicblock-sections=, let the front-end handle the case where the file
doesnt exist. The driver only checks if the option syntax is right.

Differential Revision: https://reviews.llvm.org/D89500

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Let -basic-block-sections=labels emit basicblock metadata in a new .bb_addr_map section, instead of emitting special unary-encoded symbols.

This patch introduces the new .bb_addr_map section feature

Let -basic-block-sections=labels emit basicblock metadata in a new .bb_addr_map section, instead of emitting special unary-encoded symbols.

This patch introduces the new .bb_addr_map section feature which allows us to emit the bits needed for mapping binary profiles to basic blocks into a separate section.
The format of the emitted data is represented as follows. It includes a header for every function:

| Address of the function | -> 8 bytes (pointer size)
| Number of basic blocks in this function (>0) | -> ULEB128

The header is followed by a BB record for every basic block. These records are ordered in the same order as MachineBasicBlocks are placed in the function. Each BB Info is structured as follows:

| Offset of the basic block relative to function begin | -> ULEB128
| Binary size of the basic block | -> ULEB128
| BB metadata | -> ULEB128 [ MBB.isReturn() OR MBB.hasTailCall() << 1 OR MBB.isEHPad() << 2 ]

The new feature will replace the existing "BB labels" functionality with -basic-block-sections=labels.
The .bb_addr_map section scrubs the specially-encoded BB symbols from the binary and makes it friendly to profilers and debuggers.
Furthermore, the new feature reduces the binary size overhead from 70% bloat to only 12%.

For more information and results please refer to the RFC: https://lists.llvm.org/pipermail/llvm-dev/2020-July/143512.html

Reviewed By: MaskRay, snehasish

Differential Revision: https://reviews.llvm.org/D85408

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Options for Basic Block Sections, enabled in D68063 and D73674.

This patch adds clang options:
-fbasic-block-sections={all,<filename>,labels,none} and
-funique-basic-block-section-names.
LLVM Suppor

Options for Basic Block Sections, enabled in D68063 and D73674.

This patch adds clang options:
-fbasic-block-sections={all,<filename>,labels,none} and
-funique-basic-block-section-names.
LLVM Support for basic block sections is already enabled.

+ -fbasic-block-sections={all, <file>, labels, none} : Enables/Disables basic
block sections for all or a subset of basic blocks. "labels" only enables
basic block symbols.
+ -funique-basic-block-section-names: Enables unique section names for
basic block sections, disabled by default.

Differential Revision: https://reviews.llvm.org/D68049

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