Indirect call wrapping helps MSanDR (dynamic instrumentation companion tool
for MSan) to catch all cases where execution leaves a compiler-instrumented
module by allowing the tool to rewrite targets of indirect calls.
This change is an optimization that skips wrapping for calls when target is
inside the current module. This relies on the linker providing symbols at the
begin and end of the module code (or code + data, does not really matter).
Gold linker provides such symbols by default. GNU (BFD) linker needs a link
flag: -Wl,--defsym=__executable_start=0.
More info:
https://code.google.com/p/memory-sanitizer/wiki/MSanDR#Native_exec
llvm-svn: 194697
This reduces the number of "write" syscalls performed to print a single
stack frame description, and makes sanitizer output less intermixed with
program output. Also, add a number of unit tests.
llvm-svn: 194686
If a null call target is provided, don't emit a dummy call. This
allows the runtime to reserve as little nop space as it needs without
the requirement of emitting a call.
llvm-svn: 194676
This allows to only link in the needed targets, reducing binary
size and more importantly link time.
Note that this is an incomplete implementation: currently,
LLVM does not have the plumbing which would allow to conditionally
link in AsmPrinter, AsmParser and Disassembler for the targets
which support them. This should be improved in the future.
llvm-svn: 194670
There is nothing special about quotes and newlines from the object
file point of view, only the assembler has to worry about expanding
the \n and \".
This patch then removes the special handling from the Mangler.
llvm-svn: 194667
YAML files tend to be very large compared to binary formats because of ASCII
format inefficiency. And the YAML reader consumes an excessively large amount
of memory when parsing a large file. It's very slow too.
For example, I observed that 6MB executable became 120MB YAML file, and the
YAML reader consumed more than 1.5GB memory to load it. The YAML reader even
caused OOM error on 32 bit, causing the entire process to fail.
This patch sets the limit on the YAML file size the linker will try to load in
the RoundTripYAML test as a safeguard.
llvm-svn: 194666
Also refine test case to capture the intention of this suppression. Essentially
some developers use __bridge_transfer as if it were a safe CFRelease.
llvm-svn: 194663
This is useful for debugging issues in the BlockFrequency implementation since
one can easily visualize where probability mass and other errors occur in the
propagation.
llvm-svn: 194654
bit fields of zero size. Warnings are generated in C++ mode and if
only such type is defined inside extern "C" block.
The patch fixed PR5065.
Differential Revision: http://llvm-reviews.chandlerc.com/D2151
llvm-svn: 194653