r201716 - Moving the documentation for the ARM interrupt attribute into AttrDocs.
Aaron Ballman
aaron at aaronballman.com
Wed Feb 19 13:12:24 PST 2014
Author: aaronballman
Date: Wed Feb 19 15:12:23 2014
New Revision: 201716
URL: http://llvm.org/viewvc/llvm-project?rev=201716&view=rev
Log:
Moving the documentation for the ARM interrupt attribute into AttrDocs.
Modified:
cfe/trunk/docs/LanguageExtensions.rst
cfe/trunk/include/clang/Basic/Attr.td
cfe/trunk/include/clang/Basic/AttrDocs.td
Modified: cfe/trunk/docs/LanguageExtensions.rst
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/LanguageExtensions.rst?rev=201716&r1=201715&r2=201716&view=diff
==============================================================================
--- cfe/trunk/docs/LanguageExtensions.rst (original)
+++ cfe/trunk/docs/LanguageExtensions.rst Wed Feb 19 15:12:23 2014
@@ -1629,48 +1629,6 @@ Which compiles to (on X86-32):
movl %gs:(%eax), %eax
ret
-ARM Language Extensions
------------------------
-
-Interrupt attribute
-^^^^^^^^^^^^^^^^^^^
-
-Clang supports the GNU style ``__attribute__((interrupt("TYPE")))`` attribute on
-ARM targets. This attribute may be attached to a function definition and
-instructs the backend to generate appropriate function entry/exit code so that
-it can be used directly as an interrupt service routine.
-
-The parameter passed to the interrupt attribute is optional, but if
-provided it must be a string literal with one of the following values: "IRQ",
-"FIQ", "SWI", "ABORT", "UNDEF".
-
-The semantics are as follows:
-
-- If the function is AAPCS, Clang instructs the backend to realign the stack to
- 8 bytes on entry. This is a general requirement of the AAPCS at public
- interfaces, but may not hold when an exception is taken. Doing this allows
- other AAPCS functions to be called.
-- If the CPU is M-class this is all that needs to be done since the architecture
- itself is designed in such a way that functions obeying the normal AAPCS ABI
- constraints are valid exception handlers.
-- If the CPU is not M-class, the prologue and epilogue are modified to save all
- non-banked registers that are used, so that upon return the user-mode state
- will not be corrupted. Note that to avoid unnecessary overhead, only
- general-purpose (integer) registers are saved in this way. If VFP operations
- are needed, that state must be saved manually.
-
- Specifically, interrupt kinds other than "FIQ" will save all core registers
- except "lr" and "sp". "FIQ" interrupts will save r0-r7.
-- If the CPU is not M-class, the return instruction is changed to one of the
- canonical sequences permitted by the architecture for exception return. Where
- possible the function itself will make the necessary "lr" adjustments so that
- the "preferred return address" is selected.
-
- Unfortunately the compiler is unable to make this guarantee for an "UNDEF"
- handler, where the offset from "lr" to the preferred return address depends on
- the execution state of the code which generated the exception. In this case
- a sequence equivalent to "movs pc, lr" will be used.
-
Extensions for Static Analysis
==============================
Modified: cfe/trunk/include/clang/Basic/Attr.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/Attr.td?rev=201716&r1=201715&r2=201716&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/Attr.td (original)
+++ cfe/trunk/include/clang/Basic/Attr.td Wed Feb 19 15:12:23 2014
@@ -389,7 +389,7 @@ def ARMInterrupt : InheritableAttr, Targ
1>];
let ParseKind = "Interrupt";
let HasCustomParsing = 1;
- let Documentation = [Undocumented];
+ let Documentation = [ARMInterruptDocs];
}
def AsmLabel : InheritableAttr {
Modified: cfe/trunk/include/clang/Basic/AttrDocs.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/AttrDocs.td?rev=201716&r1=201715&r2=201716&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/AttrDocs.td (original)
+++ cfe/trunk/include/clang/Basic/AttrDocs.td Wed Feb 19 15:12:23 2014
@@ -457,3 +457,44 @@ Here is an example:
}
}];
}
+
+def ARMInterruptDocs : Documentation {
+ let Category = DocCatFunction;
+ let Content = [{
+Clang supports the GNU style ``__attribute__((interrupt("TYPE")))`` attribute on
+ARM targets. This attribute may be attached to a function definition and
+instructs the backend to generate appropriate function entry/exit code so that
+it can be used directly as an interrupt service routine.
+
+The parameter passed to the interrupt attribute is optional, but if
+provided it must be a string literal with one of the following values: "IRQ",
+"FIQ", "SWI", "ABORT", "UNDEF".
+
+The semantics are as follows:
+
+- If the function is AAPCS, Clang instructs the backend to realign the stack to
+ 8 bytes on entry. This is a general requirement of the AAPCS at public
+ interfaces, but may not hold when an exception is taken. Doing this allows
+ other AAPCS functions to be called.
+- If the CPU is M-class this is all that needs to be done since the architecture
+ itself is designed in such a way that functions obeying the normal AAPCS ABI
+ constraints are valid exception handlers.
+- If the CPU is not M-class, the prologue and epilogue are modified to save all
+ non-banked registers that are used, so that upon return the user-mode state
+ will not be corrupted. Note that to avoid unnecessary overhead, only
+ general-purpose (integer) registers are saved in this way. If VFP operations
+ are needed, that state must be saved manually.
+
+ Specifically, interrupt kinds other than "FIQ" will save all core registers
+ except "lr" and "sp". "FIQ" interrupts will save r0-r7.
+- If the CPU is not M-class, the return instruction is changed to one of the
+ canonical sequences permitted by the architecture for exception return. Where
+ possible the function itself will make the necessary "lr" adjustments so that
+ the "preferred return address" is selected.
+
+ Unfortunately the compiler is unable to make this guarantee for an "UNDEF"
+ handler, where the offset from "lr" to the preferred return address depends on
+ the execution state of the code which generated the exception. In this case
+ a sequence equivalent to "movs pc, lr" will be used.
+ }];
+}
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