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[Driver][ARM] parse version of arm/thumb architecture correctly 

Summary:
If you execute the following commandline multiple times, the behavior was not always the same:
  clang++ --target=thumbv7em-none-windows-eabi-coff -march=armv7-m -mcpu=cortex-m7 -o temp.obj -c -x c++ empty.cpp

Most of the time the compilation succeeded, but sometimes clang reported this error:
  clang++: error: the target architecture 'thumbv7em' is not supported by the target 'thumbv7em-none-windows-eabi'

The cause of the inconsistent behavior was the uninitialized variable Version.

With these commandline arguments, the variable Version was not set by getAsInteger(),
because it cannot parse a number from the substring "7em" (of "thumbv7em").
To get a consistent behaviour, it's enough to initialize the variable Version to zero.
Zero is smaller than 7, so the comparison will be true.
Then the command always fails with the error message seen above.

By using consumeInteger() instead of getAsInteger() we get 7 from the substring "7em"
and the command does not fail.

Reviewers: compnerd, danielkiss

Reviewed By: danielkiss

Subscribers: danielkiss, kristof.beyls, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D75453
This commit is contained in:
Daniel Kiss 2020-07-01 11:15:52 +02:00
parent 8180a39965
commit 070acb1d1e
2 changed files with 12 additions and 3 deletions
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7
clang/lib/Driver/ToolChains/Clang.cpp
View File

@ -4041,9 +4041,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
if (Triple.isOSWindows() && (Triple.getArch() == llvm::Triple::arm ||
Triple.getArch() == llvm::Triple::thumb)) {
unsigned Offset = Triple.getArch() == llvm::Triple::arm ? 4 : 6;
unsigned Version;
Triple.getArchName().substr(Offset).getAsInteger(10, Version);
if (Version < 7)
unsigned Version = 0;
bool Failure =
Triple.getArchName().substr(Offset).consumeInteger(10, Version);
if (Failure || Version < 7)
D.Diag(diag::err_target_unsupported_arch) << Triple.getArchName()
<< TripleStr;
}

8
clang/test/Driver/windows-thumbv7em.cpp Normal file
View File

@ -0,0 +1,8 @@
// RUN: %clang -target thumb-none-windows-eabi-coff -mcpu=cortex-m7 -### -c %s 2>&1 \
// RUN: | FileCheck %s --check-prefix CHECK-V7
// CHECK-V7-NOT: error: the target architecture 'thumbv7em' is not supported by the target 'thumbv7em-none-windows-eabi'
// RUN: %clang -target thumb-none-windows-eabi-coff -mcpu=cortex-m1 -### -c %s 2>&1 \
// RUN: | FileCheck %s --check-prefix CHECK-V6
// CHECK-V6: error: the target architecture 'thumbv6m' is not supported by the target 'thumbv6m-none-windows-eabi'